Merge pull request #5 from Clever/INFRA-2405-new-consumer-interface

Implemented new consumer interface as well as example consumer
2017-07-24 13:12:43 -07:00 · 2017-07-24 13:12:43 -07:00 · 4c6d8453ef
commit 4c6d8453ef
parent aef51b0801 212ec45d88
21 changed files with 3368 additions and 23 deletions
--- a/25
+++ b/25
@ -1,6 +1,10 @@
+include golang.mk
+.DEFAULT_GOAL := test # override default goal set in library makefile
+
 SHELL := /bin/bash
 JAR_DIR := jars
 PKG := github.com/Clever/amazon-kinesis-client-go
+PKGS := $(shell go list ./... | grep -v /vendor )
 .PHONY: download_jars run build

 URL_PREFIX := http://search.maven.org/remotecontent?filepath=
@ -30,6 +34,8 @@ EMPTY :=
 SPACE := $(EMPTY) $(EMPTY)
 JAVA_CLASS_PATH := $(subst $(SPACE),:,$(JARS_TO_DOWNLOAD))

+CONSUMER ?= consumer
+
 $(JARS_TO_DOWNLOAD):
 	mkdir -p `dirname $@`
 	curl -s -L -o $@ -O $(URL_PREFIX)`echo $@ | sed 's/$(JAR_DIR)\///g'`
@ -37,8 +43,23 @@ $(JARS_TO_DOWNLOAD):
 download_jars: $(JARS_TO_DOWNLOAD)

 build:
-	CGO_ENABLED=0 go build -installsuffix cgo -o build/consumer $(PKG)/cmd/consumer
+	CGO_ENABLED=0 go build -installsuffix cgo -o build/$(CONSUMER) $(PKG)/cmd/$(CONSUMER)

 run: build download_jars
 	command -v java >/dev/null 2>&1 || { echo >&2 "Java not installed. Install java!"; exit 1; }
-	java -cp $(JAVA_CLASS_PATH) com.amazonaws.services.kinesis.multilang.MultiLangDaemon consumer.properties
+	java -cp $(JAVA_CLASS_PATH) \
+	com.amazonaws.services.kinesis.multilang.MultiLangDaemon \
+	$(CONSUMER).properties
+
+bench:
+	go test -bench=. github.com/Clever/amazon-kinesis-client-go/decode/
+
+test: $(PKGS)
+$(PKGS): golang-test-all-deps
+	$(call golang-test-all,$@)
+
+$(GOPATH)/bin/glide:
+	@go get github.com/Masterminds/glide
+
+install_deps: $(GOPATH)/bin/glide
+	@$(GOPATH)/bin/glide install
--- a/batchconsumer.properties
+++ b/batchconsumer.properties
@ -0,0 +1,83 @@
+# The script that abides by the multi-language protocol. This script will
+# be executed by the MultiLangDaemon, which will communicate with this script
+# over STDIN and STDOUT according to the multi-language protocol.
+executableName = build/batchconsumer
+
+# The name of an Amazon Kinesis stream to process.
+streamName = test-stream
+
+# Used by the KCL as the name of this application. Will be used as the name
+# of an Amazon DynamoDB table which will store the lease and checkpoint
+# information for workers with this application name
+applicationName = KCLGoExample
+
+# Users can change the credentials provider the KCL will use to retrieve credentials.
+# The DefaultAWSCredentialsProviderChain checks several other providers, which is
+# described here:
+# http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/DefaultAWSCredentialsProviderChain.html
+AWSCredentialsProvider = DefaultAWSCredentialsProviderChain
+
+# Appended to the user agent of the KCL. Does not impact the functionality of the
+# KCL in any other way.
+processingLanguage = golang
+
+# Valid options at TRIM_HORIZON or LATEST.
+# See http://docs.aws.amazon.com/kinesis/latest/APIReference/API_GetShardIterator.html#API_GetShardIterator_RequestSyntax
+initialPositionInStream = TRIM_HORIZON
+
+# The following properties are also available for configuring the KCL Worker that is created
+# by the MultiLangDaemon.
+
+# The KCL defaults to us-east-1
+regionName = us-west-1
+
+# Fail over time in milliseconds. A worker which does not renew it's lease within this time interval
+# will be regarded as having problems and it's shards will be assigned to other workers.
+# For applications that have a large number of shards, this msy be set to a higher number to reduce
+# the number of DynamoDB IOPS required for tracking leases
+#failoverTimeMillis = 10000
+
+# A worker id that uniquely identifies this worker among all workers using the same applicationName
+# If this isn't provided a MultiLangDaemon instance will assign a unique workerId to itself.
+#workerId = 
+
+# Shard sync interval in milliseconds - e.g. wait for this long between shard sync tasks.
+#shardSyncIntervalMillis = 60000
+
+# Max records to fetch from Kinesis in a single GetRecords call.
+#maxRecords = 10000
+
+# Idle time between record reads in milliseconds.
+#idleTimeBetweenReadsInMillis = 1000
+
+# Enables applications flush/checkpoint (if they have some data "in progress", but don't get new data for while)
+#callProcessRecordsEvenForEmptyRecordList = false
+
+# Interval in milliseconds between polling to check for parent shard completion.
+# Polling frequently will take up more DynamoDB IOPS (when there are leases for shards waiting on
+# completion of parent shards).
+#parentShardPollIntervalMillis = 10000
+
+# Cleanup leases upon shards completion (don't wait until they expire in Kinesis).
+# Keeping leases takes some tracking/resources (e.g. they need to be renewed, assigned), so by default we try
+# to delete the ones we don't need any longer.
+#cleanupLeasesUponShardCompletion = true
+
+# Backoff time in milliseconds for Amazon Kinesis Client Library tasks (in the event of failures).
+#taskBackoffTimeMillis = 500
+
+# Buffer metrics for at most this long before publishing to CloudWatch.
+#metricsBufferTimeMillis = 10000
+
+# Buffer at most this many metrics before publishing to CloudWatch.
+#metricsMaxQueueSize = 10000
+
+# KCL will validate client provided sequence numbers with a call to Amazon Kinesis before checkpointing for calls
+# to RecordProcessorCheckpointer#checkpoint(String) by default.
+#validateSequenceNumberBeforeCheckpointing = true
+
+# The maximum number of active threads for the MultiLangDaemon to permit.
+# If a value is provided then a FixedThreadPool is used with the maximum
+# active threads set to the provided value. If a non-positive integer or no
+# value is provided a CachedThreadPool is used.
+#maxActiveThreads = 0
--- a/batchconsumer/batcher/message_batcher.go
+++ b/batchconsumer/batcher/message_batcher.go
@ -0,0 +1,194 @@
+package batcher
+
+import (
+	"fmt"
+	"math/big"
+	"sync"
+	"time"
+)
+
+// SequencePair a convience way to pass around a Sequence / SubSequence pair
+type SequencePair struct {
+	Sequence    *big.Int
+	SubSequence int
+}
+
+func (s SequencePair) IsEmpty() bool {
+	return s.Sequence == nil
+}
+
+func (s SequencePair) IsLessThan(pair SequencePair) bool {
+	if s.IsEmpty() || pair.IsEmpty() { // empty pairs are incomparable
+		return false
+	}
+
+	cmp := s.Sequence.Cmp(pair.Sequence)
+	if cmp == -1 {
+		return true
+	}
+	if cmp == 1 {
+		return false
+	}
+
+	return s.SubSequence < pair.SubSequence
+}
+
+// Sync is used to allow a writer to syncronize with the batcher.
+// The writer declares how to write messages (via its `SendBatch` method), while the batcher
+// keeps track of messages written
+type Sync interface {
+	SendBatch(batch [][]byte)
+}
+
+// Batcher interface
+type Batcher interface {
+	// AddMesage to the batch
+	AddMessage(msg []byte, sequencePair SequencePair) error
+	// Flush all messages from the batch
+	Flush()
+	// SmallestSeqPair returns the smallest SequenceNumber and SubSequence number in
+	// the current batch
+	SmallestSequencePair() SequencePair
+}
+
+type msgPack struct {
+	msg          []byte
+	sequencePair SequencePair
+}
+
+type batcher struct {
+	mux sync.Mutex
+
+	flushInterval time.Duration
+	flushCount    int
+	flushSize     int
+
+	// smallestSeq are used for checkpointing
+	smallestSeq SequencePair
+
+	sync      Sync
+	msgChan   chan<- msgPack
+	flushChan chan<- struct{}
+}
+
+// New creates a new Batcher
+// - sync - synchronizes batcher with writer
+// - flushInterval - how often accumulated messages should be flushed (default 1 second).
+// - flushCount - number of messages that trigger a flush (default 10).
+// - flushSize - size of batch that triggers a flush (default 1024 * 1024 = 1 mb)
+func New(sync Sync, flushInterval time.Duration, flushCount int, flushSize int) (Batcher, error) {
+	if flushSize == 0 {
+		return nil, fmt.Errorf("flush size must be non-zero")
+	}
+	if flushCount == 0 {
+		return nil, fmt.Errorf("flush count must be non-zero")
+	}
+	if flushInterval == 0 {
+		return nil, fmt.Errorf("flush interval must be non-zero")
+	}
+
+	msgChan := make(chan msgPack)
+	flushChan := make(chan struct{})
+
+	b := &batcher{
+		flushCount:    flushCount,
+		flushInterval: flushInterval,
+		flushSize:     flushSize,
+		sync:          sync,
+		msgChan:       msgChan,
+		flushChan:     flushChan,
+	}
+
+	go b.startBatcher(msgChan, flushChan)
+
+	return b, nil
+}
+
+func (b *batcher) SmallestSequencePair() SequencePair {
+	b.mux.Lock()
+	defer b.mux.Unlock()
+
+	return b.smallestSeq
+}
+
+func (b *batcher) SetFlushInterval(dur time.Duration) {
+	b.flushInterval = dur
+}
+
+func (b *batcher) SetFlushCount(count int) {
+	b.flushCount = count
+}
+
+func (b *batcher) SetFlushSize(size int) {
+	b.flushSize = size
+}
+
+func (b *batcher) AddMessage(msg []byte, pair SequencePair) error {
+	if len(msg) <= 0 {
+		return fmt.Errorf("Empty messages can't be sent")
+	}
+
+	b.msgChan <- msgPack{msg, pair}
+	return nil
+}
+
+// updateSequenceNumbers is used to track the smallest sequenceNumber of any record in the batch.
+// When flush() is called, the batcher sends the sequence number to the writer. When the writer
+// checkpoints, it does so up to the latest message that was flushed successfully.
+func (b *batcher) updateSequenceNumbers(pair SequencePair) {
+	b.mux.Lock()
+	defer b.mux.Unlock()
+
+	if b.smallestSeq.IsEmpty() || pair.IsLessThan(b.smallestSeq) {
+		b.smallestSeq = pair
+	}
+}
+
+func (b *batcher) Flush() {
+	b.flushChan <- struct{}{}
+}
+
+func (b *batcher) batchSize(batch [][]byte) int {
+	total := 0
+	for _, msg := range batch {
+		total += len(msg)
+	}
+
+	return total
+}
+
+func (b *batcher) flush(batch [][]byte) [][]byte {
+	if len(batch) > 0 {
+		b.sync.SendBatch(batch)
+
+		b.mux.Lock()
+		b.smallestSeq = SequencePair{nil, 0}
+		b.mux.Unlock()
+	}
+	return [][]byte{}
+}
+
+func (b *batcher) startBatcher(msgChan <-chan msgPack, flushChan <-chan struct{}) {
+	batch := [][]byte{}
+
+	for {
+		select {
+		case <-time.After(b.flushInterval):
+			batch = b.flush(batch)
+		case <-flushChan:
+			batch = b.flush(batch)
+		case pack := <-msgChan:
+			size := b.batchSize(batch)
+			if b.flushSize < size+len(pack.msg) {
+				batch = b.flush(batch)
+			}
+
+			batch = append(batch, pack.msg)
+			b.updateSequenceNumbers(pack.sequencePair)
+
+			if b.flushCount <= len(batch) || b.flushSize <= b.batchSize(batch) {
+				batch = b.flush(batch)
+			}
+		}
+	}
+}
--- a/batchconsumer/batcher/message_batcher_test.go
+++ b/batchconsumer/batcher/message_batcher_test.go
@ -0,0 +1,264 @@
+package batcher
+
+import (
+	"fmt"
+	"math/big"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type batch [][]byte
+
+type MockSync struct {
+	flushChan chan struct{}
+	batches   []batch
+}
+
+func NewMockSync() *MockSync {
+	return &MockSync{
+		flushChan: make(chan struct{}, 1),
+		batches:   []batch{},
+	}
+}
+
+func (m *MockSync) SendBatch(b [][]byte) {
+	m.batches = append(m.batches, batch(b))
+	m.flushChan <- struct{}{}
+}
+
+func (m *MockSync) waitForFlush(timeout time.Duration) error {
+	select {
+	case <-m.flushChan:
+		return nil
+	case <-time.After(timeout):
+		return fmt.Errorf("timed out before flush (waited %s)", timeout.String())
+	}
+}
+
+var mockSequence = SequencePair{big.NewInt(99999), 12345}
+
+func TestBatchingByCount(t *testing.T) {
+	assert := assert.New(t)
+
+	sync := NewMockSync()
+	batcher, err := New(sync, time.Hour, 2, 1024*1024)
+	assert.NoError(err)
+
+	t.Log("Batcher respect count limit")
+	assert.NoError(batcher.AddMessage([]byte("hihi"), mockSequence))
+	assert.NoError(batcher.AddMessage([]byte("heyhey"), mockSequence))
+	assert.NoError(batcher.AddMessage([]byte("hmmhmm"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(1, len(sync.batches))
+	assert.Equal(2, len(sync.batches[0]))
+	assert.Equal("hihi", string(sync.batches[0][0]))
+	assert.Equal("heyhey", string(sync.batches[0][1]))
+
+	t.Log("Batcher doesn't send partial batches")
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.Error(err)
+}
+
+func TestBatchingByTime(t *testing.T) {
+	assert := assert.New(t)
+
+	sync := NewMockSync()
+	batcher, err := New(sync, time.Millisecond, 2000000, 1024*1024)
+	assert.NoError(err)
+
+	t.Log("Batcher sends partial batches when time expires")
+	assert.NoError(batcher.AddMessage([]byte("hihi"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(1, len(sync.batches))
+	assert.Equal(1, len(sync.batches[0]))
+	assert.Equal("hihi", string(sync.batches[0][0]))
+
+	t.Log("Batcher sends all messsages in partial batches when time expires")
+	assert.NoError(batcher.AddMessage([]byte("heyhey"), mockSequence))
+	assert.NoError(batcher.AddMessage([]byte("yoyo"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(2, len(sync.batches))
+	assert.Equal(2, len(sync.batches[1]))
+	assert.Equal("heyhey", string(sync.batches[1][0]))
+	assert.Equal("yoyo", string(sync.batches[1][1]))
+
+	t.Log("Batcher doesn't send empty batches")
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.Error(err)
+}
+
+func TestBatchingBySize(t *testing.T) {
+	assert := assert.New(t)
+
+	sync := NewMockSync()
+	batcher, err := New(sync, time.Hour, 2000000, 8)
+	assert.NoError(err)
+
+	t.Log("Large messages are sent immediately")
+	assert.NoError(batcher.AddMessage([]byte("hellohello"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(1, len(sync.batches))
+	assert.Equal(1, len(sync.batches[0]))
+	assert.Equal("hellohello", string(sync.batches[0][0]))
+
+	t.Log("Batcher tries not to exceed size limit")
+	assert.NoError(batcher.AddMessage([]byte("heyhey"), mockSequence))
+	assert.NoError(batcher.AddMessage([]byte("hihi"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(2, len(sync.batches))
+	assert.Equal(1, len(sync.batches[1]))
+	assert.Equal("heyhey", string(sync.batches[1][0]))
+
+	t.Log("Batcher sends messages that didn't fit in previous batch")
+	assert.NoError(batcher.AddMessage([]byte("yoyo"), mockSequence)) // At this point "hihi" is in the batch
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(3, len(sync.batches))
+	assert.Equal(2, len(sync.batches[2]))
+	assert.Equal("hihi", string(sync.batches[2][0]))
+	assert.Equal("yoyo", string(sync.batches[2][1]))
+
+	t.Log("Batcher doesn't send partial batches")
+	assert.NoError(batcher.AddMessage([]byte("okok"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.Error(err)
+}
+
+func TestFlushing(t *testing.T) {
+	assert := assert.New(t)
+
+	sync := NewMockSync()
+	batcher, err := New(sync, time.Hour, 2000000, 1024*1024)
+	assert.NoError(err)
+
+	t.Log("Calling flush sends pending messages")
+	assert.NoError(batcher.AddMessage([]byte("hihi"), mockSequence))
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.Error(err)
+
+	batcher.Flush()
+
+	err = sync.waitForFlush(time.Millisecond * 10)
+	assert.NoError(err)
+
+	assert.Equal(1, len(sync.batches))
+	assert.Equal(1, len(sync.batches[0]))
+	assert.Equal("hihi", string(sync.batches[0][0]))
+}
+
+func TestSendingEmpty(t *testing.T) {
+	assert := assert.New(t)
+
+	sync := NewMockSync()
+	batcher, err := New(sync, time.Second, 10, 1024*1024)
+	assert.NoError(err)
+
+	t.Log("An error is returned when an empty message is sent")
+	err = batcher.AddMessage([]byte{}, mockSequence)
+	assert.Error(err)
+	assert.Equal(err.Error(), "Empty messages can't be sent")
+}
+
+func TestUpdatingSequence(t *testing.T) {
+	assert := assert.New(t)
+
+	sync := NewMockSync()
+	b, err := New(sync, time.Second, 10, 1024*1024)
+	assert.NoError(err)
+
+	batcher := b.(*batcher)
+
+	t.Log("Initally, smallestSeq is undefined")
+	assert.Nil(batcher.SmallestSequencePair().Sequence)
+
+	expected := new(big.Int)
+
+	t.Log("After AddMessage (seq=1), smallestSeq = 1")
+	batcher.updateSequenceNumbers(SequencePair{big.NewInt(1), 1234})
+	expected.SetInt64(1)
+	seq := batcher.SmallestSequencePair()
+	assert.True(expected.Cmp(seq.Sequence) == 0)
+
+	t.Log("After AddMessage (seq=2), smallestSeq = 1 -- not updated because higher")
+	batcher.updateSequenceNumbers(SequencePair{big.NewInt(2), 1234})
+	seq = batcher.SmallestSequencePair()
+	assert.True(expected.Cmp(seq.Sequence) == 0)
+
+	t.Log("After AddMessage (seq=1), smallestSeq = 0")
+	batcher.updateSequenceNumbers(SequencePair{big.NewInt(0), 1234})
+	expected.SetInt64(0)
+	seq = batcher.SmallestSequencePair()
+	assert.True(expected.Cmp(seq.Sequence) == 0)
+
+	t.Log("Flushing batch clears smallest sequence pair")
+	assert.NoError(batcher.AddMessage([]byte("cdcd"), SequencePair{big.NewInt(2), 1234}))
+	sync.waitForFlush(time.Minute)
+	assert.Nil(batcher.SmallestSequencePair().Sequence)
+}
+
+func TestSequencePairIsLessThan(t *testing.T) {
+	assert := assert.New(t)
+
+	big10 := big.NewInt(10)
+	big5 := big.NewInt(5)
+
+	tests := []struct {
+		left   SequencePair
+		right  SequencePair
+		isLess bool
+	}{
+		{left: SequencePair{nil, 0}, right: SequencePair{nil, 0}, isLess: false},
+		{left: SequencePair{nil, 0}, right: SequencePair{big10, 0}, isLess: false},
+		{left: SequencePair{big10, 0}, right: SequencePair{nil, 0}, isLess: false},
+
+		{left: SequencePair{big5, 0}, right: SequencePair{big10, 0}, isLess: true},
+		{left: SequencePair{big5, 0}, right: SequencePair{big5, 10}, isLess: true},
+
+		{left: SequencePair{big10, 0}, right: SequencePair{big5, 0}, isLess: false},
+		{left: SequencePair{big5, 10}, right: SequencePair{big5, 0}, isLess: false},
+	}
+
+	for _, test := range tests {
+		left := test.left
+		right := test.right
+		t.Logf(
+			"Is <%s, %d> less than <%s, %d>? %t",
+			left.Sequence.String(), left.SubSequence,
+			right.Sequence.String(), right.SubSequence,
+			test.isLess,
+		)
+
+		assert.Equal(test.isLess, left.IsLessThan(right))
+	}
+}
+
+func TestSequencePairEmpty(t *testing.T) {
+	assert := assert.New(t)
+
+	assert.True(SequencePair{nil, 0}.IsEmpty())
+	assert.True(SequencePair{nil, 10000}.IsEmpty())
+
+	assert.False(SequencePair{big.NewInt(10), 0}.IsEmpty())
+	assert.False(SequencePair{big.NewInt(0), 1000}.IsEmpty())
+}
--- a/batchconsumer/consumer.go
+++ b/batchconsumer/consumer.go
@ -0,0 +1,120 @@
+package batchconsumer
+
+import (
+	"io"
+	"log"
+	"os"
+	"time"
+
+	"gopkg.in/Clever/kayvee-go.v6/logger"
+
+	"github.com/Clever/amazon-kinesis-client-go/kcl"
+)
+
+// Config used for BatchConsumer constructor.  Any empty fields are populated with defaults.
+type Config struct {
+	// DeployEnv the name of the deployment environment
+	DeployEnv string
+
+	// LogFile where consumer errors and failed log lines are saved
+	LogFile string
+	// BatchInterval the upper bound on how often SendBatch is called with accumulated messages
+	BatchInterval time.Duration
+	// BatchCount is the number of messages that triggers a SendBatch call
+	BatchCount int
+	// BatchSize is the size of a batch in bytes that triggers a SendBatch call
+	BatchSize int
+
+	// ReadRateLimit the number of records read per seconds
+	ReadRateLimit int
+	// ReadBurstLimit the max number of tokens allowed by rate limiter
+	ReadBurstLimit int
+
+	// CheckpointFreq the frequency in which a checkpoint is saved
+	CheckpointFreq time.Duration
+	// CheckpointRetries the number of times the consumer will try to save a checkpoint
+	CheckpointRetries int
+	// CheckpointRetrySleep the amount of time between checkpoint save attempts
+	CheckpointRetrySleep time.Duration
+}
+
+// BatchConsumer is responsible for marshalling
+type BatchConsumer struct {
+	kclProcess *kcl.KCLProcess
+	logfile    *os.File
+}
+
+func withDefaults(config Config) Config {
+	if config.LogFile == "" {
+		config.LogFile = "/tmp/kcl-" + time.Now().Format(time.RFC3339)
+	}
+
+	if config.BatchInterval == 0 {
+		config.BatchInterval = 10 * time.Second
+	}
+	if config.BatchCount == 0 {
+		config.BatchCount = 500
+	}
+	if config.BatchSize == 0 {
+		config.BatchSize = 4 * 1024 * 1024
+	}
+
+	if config.DeployEnv == "" {
+		config.DeployEnv = "unknown-env"
+	}
+
+	if config.ReadRateLimit == 0 {
+		config.ReadRateLimit = 300
+	}
+	if config.ReadBurstLimit == 0 {
+		config.ReadBurstLimit = int(float64(config.ReadRateLimit)*1.2 + 0.5)
+	}
+
+	if config.CheckpointFreq == 0 {
+		config.CheckpointFreq = 60 * time.Second
+	}
+	if config.CheckpointRetries == 0 {
+		config.CheckpointRetries = 5
+	}
+	if config.CheckpointRetrySleep == 0 {
+		config.CheckpointRetrySleep = 5 * time.Second
+	}
+
+	return config
+}
+
+// NewBatchConsumerFromFiles creates a batch consumer.  Readers/writers provided are used for
+// interprocess communication.
+func NewBatchConsumerFromFiles(
+	config Config, sender Sender, input io.Reader, output, errFile io.Writer,
+) *BatchConsumer {
+	config = withDefaults(config)
+
+	file, err := os.OpenFile(config.LogFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+	if err != nil {
+		log.Fatalf("Unable to create log file: %s", err.Error())
+	}
+
+	kvlog := logger.New("amazon-kinesis-client-go")
+	kvlog.SetOutput(file)
+
+	wrt := NewBatchedWriter(config, sender, kvlog)
+	kclProcess := kcl.New(input, output, errFile, wrt)
+
+	return &BatchConsumer{
+		kclProcess: kclProcess,
+		logfile:    file,
+	}
+}
+
+// NewBatchConsumer creates batch consumer.  Stdin, Stdout, and Stderr are used for interprocess
+// communication.
+func NewBatchConsumer(config Config, sender Sender) *BatchConsumer {
+	return NewBatchConsumerFromFiles(config, sender, os.Stdin, os.Stdout, os.Stderr)
+}
+
+// Start when called, the consumer begins ingesting messages.  This function blocks.
+func (b *BatchConsumer) Start() {
+	b.kclProcess.Run()
+	b.logfile.Close()
+}
--- a/batchconsumer/sender.go
+++ b/batchconsumer/sender.go
@ -0,0 +1,46 @@
+package batchconsumer
+
+import (
+	"errors"
+	"fmt"
+)
+
+// ErrMessageIgnored should be returned by ProcessMessage when it encounters a message that will
+// not be consumed
+var ErrMessageIgnored = errors.New("Message intentionally skipped by sender")
+
+// Sender an interface needed for batch consumer implementations
+type Sender interface {
+	// ProcessMessage receives a raw message and is expected to return an appropriately formatted
+	// message as well as a list of tags for that log line.  A tag corresponds to a batch that
+	// it'll be put into.  Typically tags are series names.
+	// If a message will not be consumed, ProcessMessage should return a ErrMessageIgnored error.
+	ProcessMessage(rawmsg []byte) (msg []byte, tags []string, err error)
+	// SendBatch receives a batch of messages.  All messages were given the specified tag by
+	// ProcessMessage
+	SendBatch(batch [][]byte, tag string) error
+}
+
+// PartialSendBatchError should be returned by SendBatch implementations when some messages
+// couldn't be sent to an output.  It's expected that SendBatch implementations do a "best effort"
+// before returning this error.
+type PartialSendBatchError struct {
+	// ErrMessage is a description of error that occurred
+	ErrMessage string
+	// FailedMessages a list of messages that failed to be sent
+	FailedMessages [][]byte
+}
+
+func (c PartialSendBatchError) Error() string {
+	return fmt.Sprintf("%d failed logs. %s", len(c.FailedMessages), c.ErrMessage)
+}
+
+// CatastrophicSendBatchError should be returned by SendBatch implementations when the output is
+// unreachable.  Returning this error causes this container to exit without checkpointing.
+type CatastrophicSendBatchError struct {
+	ErrMessage string
+}
+
+func (c CatastrophicSendBatchError) Error() string {
+	return fmt.Sprintf("catastrophic SendBatch error: %s", c.ErrMessage)
+}
--- a/batchconsumer/sync.go
+++ b/batchconsumer/sync.go
@ -0,0 +1,10 @@
+package batchconsumer
+
+type batcherSync struct {
+	tag    string
+	writer *batchedWriter
+}
+
+func (b *batcherSync) SendBatch(batch [][]byte) {
+	b.writer.SendBatch(batch, b.tag)
+}
--- a/batchconsumer/writer.go
+++ b/batchconsumer/writer.go
@ -0,0 +1,325 @@
+package batchconsumer
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"math/big"
+	"os"
+	"time"
+
+	"golang.org/x/time/rate"
+	kv "gopkg.in/Clever/kayvee-go.v6/logger"
+
+	"github.com/Clever/amazon-kinesis-client-go/batchconsumer/batcher"
+	"github.com/Clever/amazon-kinesis-client-go/kcl"
+	"github.com/Clever/amazon-kinesis-client-go/splitter"
+)
+
+type tagMsgPair struct {
+	tag  string
+	msg  []byte
+	pair batcher.SequencePair
+}
+
+type batchedWriter struct {
+	config Config
+	sender Sender
+	log    kv.KayveeLogger
+
+	shardID string
+
+	checkpointMsg     chan batcher.SequencePair
+	checkpointTag     chan string
+	lastProcessedPair chan batcher.SequencePair
+	batchMsg          chan tagMsgPair
+	flushBatches      chan struct{}
+
+	// Limits the number of records read from the stream
+	rateLimiter *rate.Limiter
+
+	lastProcessedSeq batcher.SequencePair
+}
+
+func NewBatchedWriter(config Config, sender Sender, log kv.KayveeLogger) *batchedWriter {
+	return &batchedWriter{
+		config: config,
+		sender: sender,
+		log:    log,
+
+		rateLimiter: rate.NewLimiter(rate.Limit(config.ReadRateLimit), config.ReadBurstLimit),
+	}
+}
+
+func (b *batchedWriter) Initialize(shardID string, checkpointer kcl.Checkpointer) error {
+	b.shardID = shardID
+	b.checkpointMsg = make(chan batcher.SequencePair)
+	b.startCheckpointListener(checkpointer, b.checkpointMsg)
+
+	b.checkpointTag = make(chan string)
+	b.batchMsg = make(chan tagMsgPair)
+	b.flushBatches = make(chan struct{})
+	b.lastProcessedPair = make(chan batcher.SequencePair)
+	b.startMessageHandler(b.batchMsg, b.checkpointTag, b.lastProcessedPair, b.flushBatches)
+
+	return nil
+}
+
+// handleCheckpointError returns true if checkout should be tried again.  Returns false otherwise.
+func (b *batchedWriter) handleCheckpointError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	cperr, ok := err.(kcl.CheckpointError)
+	if !ok {
+		b.log.ErrorD("unknown-checkpoint-error", kv.M{"msg": err.Error(), "shard-id": b.shardID})
+		return true
+	}
+
+	switch cperr.Error() {
+	case "ShutdownException": // Skips checkpointing
+		b.log.ErrorD("shutdown-checkpoint-exception", kv.M{
+			"msg": err.Error(), "shard-id": b.shardID,
+		})
+		return false
+	case "ThrottlingException":
+		b.log.ErrorD("checkpoint-throttle", kv.M{"shard-id": b.shardID})
+	case "InvalidStateException":
+		b.log.ErrorD("invalid-checkpoint-state", kv.M{"shard-id": b.shardID})
+	default:
+		b.log.ErrorD("checkpoint-error", kv.M{"shard-id": b.shardID, "msg": err})
+	}
+
+	return true
+}
+
+func (b *batchedWriter) startCheckpointListener(
+	checkpointer kcl.Checkpointer, checkpointMsg <-chan batcher.SequencePair,
+) {
+	go func() {
+		lastCheckpoint := time.Now()
+
+		for {
+			seq := <-checkpointMsg
+
+			// This is a write throttle to ensure we don't checkpoint faster than
+			// b.config.CheckpointFreq.  The latest seq number is always used.
+			for time.Now().Sub(lastCheckpoint) < b.config.CheckpointFreq {
+				select {
+				case seq = <-checkpointMsg: // Keep updating checkpoint seq while waiting
+				case <-time.NewTimer(b.config.CheckpointFreq - time.Now().Sub(lastCheckpoint)).C:
+				}
+			}
+
+			retry := true
+			for n := 0; retry && n < b.config.CheckpointRetries+1; n++ {
+				str := seq.Sequence.String()
+				err := checkpointer.Checkpoint(&str, &seq.SubSequence)
+				if err == nil { // Successfully checkpointed!
+					lastCheckpoint = time.Now()
+					break
+				}
+
+				retry = b.handleCheckpointError(err)
+
+				if n == b.config.CheckpointRetries {
+					b.log.ErrorD("checkpoint-retries", kv.M{"attempts": b.config.CheckpointRetries})
+					retry = false
+				}
+
+				if retry {
+					time.Sleep(b.config.CheckpointRetrySleep)
+				}
+			}
+		}
+	}()
+}
+
+func (b *batchedWriter) createBatcher(tag string) batcher.Batcher {
+	sync := &batcherSync{
+		tag:    tag,
+		writer: b,
+	}
+	batch, err := batcher.New(sync, b.config.BatchInterval, b.config.BatchCount, b.config.BatchSize)
+	if err != nil {
+		b.log.ErrorD("create-batcher", kv.M{"msg": err.Error(), "tag": tag})
+	}
+
+	return batch
+}
+
+// startMessageDistributer starts a go-routine that routes messages to batches.  It's in uses a
+// go routine to avoid racey conditions.
+func (b *batchedWriter) startMessageHandler(
+	batchMsg <-chan tagMsgPair, checkpointTag <-chan string, lastPair <-chan batcher.SequencePair,
+	flushBatches <-chan struct{},
+) {
+	go func() {
+		var lastProcessedPair batcher.SequencePair
+		batchers := map[string]batcher.Batcher{}
+		areBatchersEmpty := true
+
+		for {
+			select {
+			case tmp := <-batchMsg:
+				batcher, ok := batchers[tmp.tag]
+				if !ok {
+					batcher = b.createBatcher(tmp.tag)
+					batchers[tmp.tag] = batcher
+				}
+
+				err := batcher.AddMessage(tmp.msg, tmp.pair)
+				if err != nil {
+					b.log.ErrorD("add-message", kv.M{
+						"err": err.Error(), "msg": string(tmp.msg), "tag": tmp.tag,
+					})
+				}
+				areBatchersEmpty = false
+			case tag := <-checkpointTag:
+				smallest := lastProcessedPair
+				isAllEmpty := true
+
+				for name, batch := range batchers {
+					if tag == name {
+						continue
+					}
+
+					pair := batch.SmallestSequencePair()
+					if pair.IsEmpty() { // Occurs when batch has no items
+						continue
+					}
+
+					if pair.IsLessThan(smallest) {
+						smallest = pair
+					}
+
+					isAllEmpty = false
+				}
+
+				if !smallest.IsEmpty() {
+					b.checkpointMsg <- smallest
+				}
+				areBatchersEmpty = isAllEmpty
+			case pair := <-lastPair:
+				if areBatchersEmpty {
+					b.checkpointMsg <- pair
+				}
+				lastProcessedPair = pair
+			case <-flushBatches:
+				for _, batch := range batchers {
+					batch.Flush()
+				}
+				b.checkpointMsg <- lastProcessedPair
+				areBatchersEmpty = true
+			}
+		}
+	}()
+}
+
+func (b *batchedWriter) splitMessageIfNecessary(record []byte) ([][]byte, error) {
+	// We handle two types of records:
+	// - records emitted from CWLogs Subscription
+	// - records emiited from KPL
+	if !splitter.IsGzipped(record) {
+		// Process a single message, from KPL
+		return [][]byte{record}, nil
+	}
+
+	// Process a batch of messages from a CWLogs Subscription
+	return splitter.GetMessagesFromGzippedInput(record, b.config.DeployEnv == "production")
+}
+
+func (b *batchedWriter) ProcessRecords(records []kcl.Record) error {
+	var pair batcher.SequencePair
+	prevPair := b.lastProcessedSeq
+
+	for _, record := range records {
+		// Wait until rate limiter permits one more record to be processed
+		b.rateLimiter.Wait(context.Background())
+
+		seq := new(big.Int)
+		if _, ok := seq.SetString(record.SequenceNumber, 10); !ok { // Validating sequence
+			return fmt.Errorf("could not parse sequence number '%s'", record.SequenceNumber)
+		}
+
+		pair = batcher.SequencePair{seq, record.SubSequenceNumber}
+		if prevPair.IsEmpty() { // Handles on-start edge case where b.lastProcessSeq is empty
+			prevPair = pair
+		}
+
+		data, err := base64.StdEncoding.DecodeString(record.Data)
+		if err != nil {
+			return err
+		}
+
+		messages, err := b.splitMessageIfNecessary(data)
+		if err != nil {
+			return err
+		}
+		for _, rawmsg := range messages {
+			msg, tags, err := b.sender.ProcessMessage(rawmsg)
+
+			if err == ErrMessageIgnored {
+				continue // Skip message
+			} else if err != nil {
+				b.log.ErrorD("process-message", kv.M{"msg": err.Error(), "rawmsg": string(rawmsg)})
+				continue // Don't stop processing messages because of one bad message
+			}
+
+			if len(tags) == 0 {
+				b.log.ErrorD("no-tags", kv.M{"rawmsg": string(rawmsg)})
+				return fmt.Errorf("No tags provided by consumer for log: %s", string(rawmsg))
+			}
+
+			for _, tag := range tags {
+				if tag == "" {
+					b.log.ErrorD("blank-tag", kv.M{"rawmsg": string(rawmsg)})
+					return fmt.Errorf("Blank tag provided by consumer for log: %s", string(rawmsg))
+				}
+
+				// Use second to last sequence number to ensure we don't checkpoint a message before
+				// it's been sent.  When batches are sent, conceptually we first find the smallest
+				// sequence number amount all the batch (let's call it A).  We then checkpoint at
+				// the A-1 sequence number.
+				b.batchMsg <- tagMsgPair{tag, msg, prevPair}
+			}
+		}
+
+		prevPair = pair
+		b.lastProcessedPair <- pair
+	}
+	b.lastProcessedSeq = pair
+
+	return nil
+}
+
+func (b *batchedWriter) SendBatch(batch [][]byte, tag string) {
+	err := b.sender.SendBatch(batch, tag)
+	switch e := err.(type) {
+	case nil: // Do nothing
+	case PartialSendBatchError:
+		b.log.ErrorD("send-batch", kv.M{"msg": e.Error()})
+		for _, line := range e.FailedMessages {
+			b.log.ErrorD("failed-log", kv.M{"log": line})
+		}
+	case CatastrophicSendBatchError:
+		b.log.CriticalD("send-batch", kv.M{"msg": e.Error()})
+		os.Exit(1)
+	default:
+		b.log.CriticalD("send-batch", kv.M{"msg": e.Error()})
+		os.Exit(1)
+	}
+
+	b.checkpointTag <- tag
+}
+
+func (b *batchedWriter) Shutdown(reason string) error {
+	if reason == "TERMINATE" {
+		b.log.InfoD("terminate-signal", kv.M{"shard-id": b.shardID})
+		b.flushBatches <- struct{}{}
+	} else {
+		b.log.ErrorD("shutdown-failover", kv.M{"shard-id": b.shardID, "reason": reason})
+	}
+	return nil
+}
--- a/batchconsumer/writer_test.go
+++ b/batchconsumer/writer_test.go
@ -0,0 +1,372 @@
+package batchconsumer
+
+import (
+	"encoding/base64"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/Clever/kayvee-go.v6/logger"
+
+	"github.com/Clever/amazon-kinesis-client-go/kcl"
+)
+
+type ignoringSender struct{}
+
+func (i ignoringSender) ProcessMessage(rawmsg []byte) (msg []byte, tags []string, err error) {
+	return nil, nil, ErrMessageIgnored
+}
+
+func (i ignoringSender) SendBatch(batch [][]byte, tag string) error {
+	panic("SendBatch Should never be called.  ProcessMessage ignores all messasges.")
+}
+
+type tagBatch struct {
+	tag   string
+	batch [][]byte
+}
+type msgAsTagSender struct {
+	batches   map[string][][][]byte
+	saveBatch chan tagBatch
+	shutdown  chan struct{}
+}
+
+func NewMsgAsTagSender() *msgAsTagSender {
+	sender := &msgAsTagSender{
+		batches:   map[string][][][]byte{},
+		saveBatch: make(chan tagBatch),
+		shutdown:  make(chan struct{}),
+	}
+
+	sender.startBatchSaver(sender.saveBatch, sender.shutdown)
+
+	return sender
+}
+
+func (i *msgAsTagSender) startBatchSaver(saveBatch <-chan tagBatch, shutdown <-chan struct{}) {
+	go func() {
+		for {
+			select {
+			case tb := <-saveBatch:
+				batches, ok := i.batches[tb.tag]
+				if !ok {
+					batches = [][][]byte{}
+				}
+				i.batches[tb.tag] = append(batches, tb.batch)
+			case <-shutdown:
+				return
+			}
+		}
+	}()
+}
+
+func (i *msgAsTagSender) ProcessMessage(rawmsg []byte) (msg []byte, tags []string, err error) {
+	if "ignore" == string(rawmsg) {
+		return nil, nil, ErrMessageIgnored
+	}
+
+	return rawmsg, []string{string(rawmsg)}, nil
+}
+
+func (i *msgAsTagSender) SendBatch(batch [][]byte, tag string) error {
+	i.saveBatch <- tagBatch{tag, batch}
+	return nil
+}
+
+func (i *msgAsTagSender) Shutdown() {
+	i.shutdown <- struct{}{}
+}
+
+type mockCheckpointer struct {
+	recievedSequences []string
+	checkpoint        chan string
+	done              chan struct{}
+	timeout           chan struct{}
+	shutdown          chan struct{}
+}
+
+func NewMockCheckpointer(maxSeq string, timeout time.Duration) *mockCheckpointer {
+	mcp := &mockCheckpointer{
+		checkpoint: make(chan string),
+		done:       make(chan struct{}, 1),
+		timeout:    make(chan struct{}, 1),
+		shutdown:   make(chan struct{}),
+	}
+	mcp.startWaiter(maxSeq, timeout)
+
+	return mcp
+}
+
+func (m *mockCheckpointer) startWaiter(maxSeq string, timeout time.Duration) {
+	go func() {
+		for {
+			select {
+			case seq := <-m.checkpoint:
+				m.recievedSequences = append(m.recievedSequences, seq)
+				if seq == maxSeq {
+					m.done <- struct{}{}
+				}
+			case <-time.NewTimer(timeout).C:
+				m.timeout <- struct{}{}
+			case <-m.shutdown:
+				return
+			}
+		}
+	}()
+}
+func (m *mockCheckpointer) wait() error {
+	select {
+	case <-m.done:
+		return nil
+	case <-m.timeout:
+		return fmt.Errorf("timeout waiting for checkpoints")
+	}
+}
+func (m *mockCheckpointer) Shutdown() {
+	m.shutdown <- struct{}{}
+}
+func (m *mockCheckpointer) Checkpoint(sequenceNumber *string, subSequenceNumber *int) error {
+	m.checkpoint <- *sequenceNumber
+	return nil
+}
+func (m *mockCheckpointer) CheckpointWithRetry(
+	sequenceNumber *string, subSequenceNumber *int, retryCount int,
+) error {
+	return m.Checkpoint(sequenceNumber, subSequenceNumber)
+}
+
+func encode(str string) string {
+	return base64.StdEncoding.EncodeToString([]byte(str))
+}
+
+func TestProcessRecordsIgnoredMessages(t *testing.T) {
+	assert := assert.New(t)
+
+	mocklog := logger.New("testing")
+	mockconfig := withDefaults(Config{
+		BatchInterval:  10 * time.Millisecond,
+		CheckpointFreq: 20 * time.Millisecond,
+	})
+	mockcheckpointer := NewMockCheckpointer("4", 5*time.Second)
+
+	wrt := NewBatchedWriter(mockconfig, ignoringSender{}, mocklog)
+	wrt.Initialize("test-shard", mockcheckpointer)
+
+	err := wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "1", Data: encode("hi")},
+		kcl.Record{SequenceNumber: "2", Data: encode("hi")},
+		kcl.Record{SequenceNumber: "3", Data: encode("hi")},
+		kcl.Record{SequenceNumber: "4", Data: encode("hi")},
+	})
+	assert.NoError(err)
+
+	err = mockcheckpointer.wait()
+	assert.NoError(err)
+}
+
+func TestProcessRecordsMutliBatchBasic(t *testing.T) {
+	assert := assert.New(t)
+
+	mocklog := logger.New("testing")
+	mockconfig := withDefaults(Config{
+		BatchInterval:  100 * time.Millisecond,
+		CheckpointFreq: 200 * time.Millisecond,
+	})
+	mockcheckpointer := NewMockCheckpointer("8", 5*time.Second)
+	mocksender := NewMsgAsTagSender()
+
+	wrt := NewBatchedWriter(mockconfig, mocksender, mocklog)
+	wrt.Initialize("test-shard", mockcheckpointer)
+
+	err := wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "1", Data: encode("tag1")},
+		kcl.Record{SequenceNumber: "2", Data: encode("tag2")},
+		kcl.Record{SequenceNumber: "3", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "4", Data: encode("tag2")},
+	})
+	assert.NoError(err)
+	err = wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "5", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "6", Data: encode("tag2")},
+		kcl.Record{SequenceNumber: "7", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "8", Data: encode("tag1")},
+	})
+	assert.NoError(err)
+
+	time.Sleep(200 * time.Millisecond) // Sleep to ensure checkpoint get flushed at least once
+
+	err = wrt.Shutdown("TERMINATE")
+	assert.NoError(err)
+
+	err = mockcheckpointer.wait()
+	assert.NoError(err)
+
+	mocksender.Shutdown()
+
+	assert.Contains(mocksender.batches, "tag1")
+	assert.Equal(1, len(mocksender.batches["tag1"]))    // One batch
+	assert.Equal(2, len(mocksender.batches["tag1"][0])) // with two items
+	assert.Equal("tag1", string(mocksender.batches["tag1"][0][0]))
+	assert.Equal("tag1", string(mocksender.batches["tag1"][0][1]))
+
+	assert.Contains(mocksender.batches, "tag2")
+	assert.Equal(1, len(mocksender.batches["tag2"]))    // One batch
+	assert.Equal(3, len(mocksender.batches["tag2"][0])) // with three items
+	assert.Equal("tag2", string(mocksender.batches["tag2"][0][0]))
+	assert.Equal("tag2", string(mocksender.batches["tag2"][0][1]))
+	assert.Equal("tag2", string(mocksender.batches["tag2"][0][2]))
+
+	assert.Contains(mocksender.batches, "tag3")
+	assert.Equal(1, len(mocksender.batches["tag3"]))    // One batch
+	assert.Equal(3, len(mocksender.batches["tag3"][0])) // with three items
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][0]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][1]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][2]))
+}
+
+func TestProcessRecordsMutliBatchWithIgnores(t *testing.T) {
+	assert := assert.New(t)
+
+	mocklog := logger.New("testing")
+	mockconfig := withDefaults(Config{
+		BatchInterval:  100 * time.Millisecond,
+		CheckpointFreq: 200 * time.Millisecond,
+	})
+	mockcheckpointer := NewMockCheckpointer("26", 5*time.Second)
+	mocksender := NewMsgAsTagSender()
+
+	wrt := NewBatchedWriter(mockconfig, mocksender, mocklog)
+	wrt.Initialize("test-shard", mockcheckpointer)
+
+	err := wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "1", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "2", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "3", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "4", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "5", Data: encode("tag1")},
+		kcl.Record{SequenceNumber: "6", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "7", Data: encode("tag2")},
+		kcl.Record{SequenceNumber: "8", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "9", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "10", Data: encode("tag2")},
+		kcl.Record{SequenceNumber: "11", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "12", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "13", Data: encode("ignore")},
+	})
+	assert.NoError(err)
+	err = wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "14", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "15", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "16", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "17", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "18", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "19", Data: encode("tag2")},
+		kcl.Record{SequenceNumber: "20", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "21", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "22", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "23", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "24", Data: encode("ignore")},
+		kcl.Record{SequenceNumber: "25", Data: encode("tag1")},
+		kcl.Record{SequenceNumber: "26", Data: encode("ignore")},
+	})
+	assert.NoError(err)
+
+	time.Sleep(200 * time.Millisecond) // Sleep to ensure checkpoint get flushed at least once
+
+	err = wrt.Shutdown("TERMINATE")
+	assert.NoError(err)
+
+	err = mockcheckpointer.wait()
+	assert.NoError(err)
+
+	mocksender.Shutdown()
+
+	assert.Contains(mocksender.batches, "tag1")
+	assert.Equal(1, len(mocksender.batches["tag1"]))    // One batch
+	assert.Equal(2, len(mocksender.batches["tag1"][0])) // with two items
+	assert.Equal("tag1", string(mocksender.batches["tag1"][0][0]))
+	assert.Equal("tag1", string(mocksender.batches["tag1"][0][1]))
+
+	assert.Contains(mocksender.batches, "tag2")
+	assert.Equal(1, len(mocksender.batches["tag2"]))    // One batch
+	assert.Equal(3, len(mocksender.batches["tag2"][0])) // with three items
+	assert.Equal("tag2", string(mocksender.batches["tag2"][0][0]))
+	assert.Equal("tag2", string(mocksender.batches["tag2"][0][1]))
+	assert.Equal("tag2", string(mocksender.batches["tag2"][0][2]))
+
+	assert.Contains(mocksender.batches, "tag3")
+	assert.Equal(1, len(mocksender.batches["tag3"]))    // One batch
+	assert.Equal(3, len(mocksender.batches["tag3"][0])) // with three items
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][0]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][1]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][2]))
+}
+
+func TestStaggeredCheckpionting(t *testing.T) {
+	assert := assert.New(t)
+
+	mocklog := logger.New("testing")
+	mockconfig := withDefaults(Config{
+		BatchCount:     2,
+		BatchInterval:  100 * time.Millisecond,
+		CheckpointFreq: 200 * time.Nanosecond,
+	})
+	mockcheckpointer := NewMockCheckpointer("9", 5*time.Second)
+	mocksender := NewMsgAsTagSender()
+
+	wrt := NewBatchedWriter(mockconfig, mocksender, mocklog)
+	wrt.Initialize("test-shard", mockcheckpointer)
+
+	err := wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "1", Data: encode("tag1")},
+		kcl.Record{SequenceNumber: "2", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "3", Data: encode("tag1")},
+		kcl.Record{SequenceNumber: "4", Data: encode("tag3")},
+	})
+	assert.NoError(err)
+	err = wrt.ProcessRecords([]kcl.Record{
+		kcl.Record{SequenceNumber: "5", Data: encode("tag1")},
+		kcl.Record{SequenceNumber: "6", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "7", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "8", Data: encode("tag3")},
+		kcl.Record{SequenceNumber: "9", Data: encode("tag3")},
+	})
+	assert.NoError(err)
+
+	time.Sleep(200 * time.Millisecond) // Sleep to ensure checkpoint get flushed at least once
+
+	err = wrt.Shutdown("TERMINATE")
+	assert.NoError(err)
+
+	err = mockcheckpointer.wait()
+	assert.NoError(err)
+
+	mocksender.Shutdown()
+	mockcheckpointer.Shutdown()
+
+	// Test to make sure writer doesn't prematurely checkpoint messages
+	// Checkpoints 5,6,7,8 will never be submitted because the 3rd "tag1" is in a batch
+	// Checkpoint 9 is submitted on shutdown when everything is being flushed
+	assert.NotContains(mockcheckpointer.recievedSequences, "5")
+	assert.NotContains(mockcheckpointer.recievedSequences, "6")
+	assert.NotContains(mockcheckpointer.recievedSequences, "7")
+	assert.NotContains(mockcheckpointer.recievedSequences, "8")
+
+	assert.Contains(mocksender.batches, "tag1")
+	assert.Equal(2, len(mocksender.batches["tag1"]))    // One batch
+	assert.Equal(2, len(mocksender.batches["tag1"][0])) // with two items
+	assert.Equal("tag1", string(mocksender.batches["tag1"][0][0]))
+	assert.Equal("tag1", string(mocksender.batches["tag1"][0][1]))
+	assert.Equal("tag1", string(mocksender.batches["tag1"][1][0]))
+
+	assert.Contains(mocksender.batches, "tag3")
+	assert.Equal(3, len(mocksender.batches["tag3"]))    // One batch
+	assert.Equal(2, len(mocksender.batches["tag3"][0])) // with three items
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][0]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][0][1]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][1][0]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][1][1]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][2][0]))
+	assert.Equal("tag3", string(mocksender.batches["tag3"][2][1]))
+}
--- a/circle.yml
+++ b/circle.yml
@ -9,9 +9,10 @@ checkout:
  - $HOME/ci-scripts/circleci/golang-move-project
 compile:
  override:
+  - make install_deps
  - make build
 test:
  override:
-  - echo TODO
+  - make test
 general:
  build_dir: ../.go_workspace/src/github.com/$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME
--- a/cmd/batchconsumer/main.go
+++ b/cmd/batchconsumer/main.go
@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"gopkg.in/Clever/kayvee-go.v6/logger"
+
+	kbc "github.com/Clever/amazon-kinesis-client-go/batchconsumer"
+)
+
+func createDummyOutput() (logger.KayveeLogger, *os.File) {
+	file, err := os.OpenFile("/tmp/example-kcl-output", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+	if err != nil {
+		log.Fatalf("Unable to create log file: %s", err.Error())
+	}
+
+	kvlog := logger.New("amazon-kinesis-client-go")
+	kvlog.SetOutput(file)
+
+	return kvlog, file
+}
+
+func main() {
+	config := kbc.Config{
+		BatchInterval: 10 * time.Second,
+		BatchCount:    500,
+		BatchSize:     4 * 1024 * 1024, // 4Mb
+		LogFile:       "/tmp/example-kcl-consumer",
+		DeployEnv:     "test-env",
+	}
+
+	output, file := createDummyOutput()
+	defer file.Close()
+
+	sender := &exampleSender{output: output}
+	consumer := kbc.NewBatchConsumer(config, sender)
+	consumer.Start()
+}
+
+type exampleSender struct {
+	output logger.KayveeLogger
+}
+
+func (e *exampleSender) ProcessMessage(rawmsg []byte) ([]byte, []string, error) {
+	if len(rawmsg)%5 == 2 {
+		return nil, nil, kbc.ErrMessageIgnored
+	}
+
+	tag1 := fmt.Sprintf("tag-%d", len(rawmsg)%5)
+	line := tag1 + ": " + string(rawmsg)
+
+	return []byte(line), []string{tag1}, nil
+}
+
+func (e *exampleSender) SendBatch(batch [][]byte, tag string) error {
+	for idx, line := range batch {
+		e.output.InfoD(tag, logger.M{"idx": idx, "line": string(line)})
+	}
+
+	return nil
+}
--- a/cmd/consumer/main.go
+++ b/cmd/consumer/main.go
@ -9,8 +9,8 @@ import (
 	"github.com/Clever/amazon-kinesis-client-go/kcl"
 )

-type SampleRecordProcessor struct {
-	checkpointer      *kcl.Checkpointer
+type sampleRecordProcessor struct {
+	checkpointer      kcl.Checkpointer
 	checkpointRetries int
 	checkpointFreq    time.Duration
 	largestSeq        *big.Int
@ -18,25 +18,25 @@ type SampleRecordProcessor struct {
 	lastCheckpoint    time.Time
 }

-func New() *SampleRecordProcessor {
-	return &SampleRecordProcessor{
+func newSampleRecordProcessor() *sampleRecordProcessor {
+	return &sampleRecordProcessor{
 		checkpointRetries: 5,
 		checkpointFreq:    60 * time.Second,
 	}
 }

-func (srp *SampleRecordProcessor) Initialize(shardID string, checkpointer *kcl.Checkpointer) error {
+func (srp *sampleRecordProcessor) Initialize(shardID string, checkpointer kcl.Checkpointer) error {
 	srp.lastCheckpoint = time.Now()
 	srp.checkpointer = checkpointer
 	return nil
 }

-func (srp *SampleRecordProcessor) shouldUpdateSequence(sequenceNumber *big.Int, subSequenceNumber int) bool {
+func (srp *sampleRecordProcessor) shouldUpdateSequence(sequenceNumber *big.Int, subSequenceNumber int) bool {
 	return srp.largestSeq == nil || sequenceNumber.Cmp(srp.largestSeq) == 1 ||
 		(sequenceNumber.Cmp(srp.largestSeq) == 0 && subSequenceNumber > srp.largestSubSeq)
 }

-func (srp *SampleRecordProcessor) ProcessRecords(records []kcl.Record) error {
+func (srp *sampleRecordProcessor) ProcessRecords(records []kcl.Record) error {
 	for _, record := range records {
 		seqNumber := new(big.Int)
 		if _, ok := seqNumber.SetString(record.SequenceNumber, 10); !ok {
@ -56,7 +56,7 @@ func (srp *SampleRecordProcessor) ProcessRecords(records []kcl.Record) error {
 	return nil
 }

-func (srp *SampleRecordProcessor) Shutdown(reason string) error {
+func (srp *sampleRecordProcessor) Shutdown(reason string) error {
 	if reason == "TERMINATE" {
 		fmt.Fprintf(os.Stderr, "Was told to terminate, will attempt to checkpoint.\n")
 		srp.checkpointer.Shutdown()
@ -72,6 +72,6 @@ func main() {
 		panic(err)
 	}
 	defer f.Close()
-	kclProcess := kcl.New(os.Stdin, os.Stdout, os.Stderr, New())
+	kclProcess := kcl.New(os.Stdin, os.Stdout, os.Stderr, newSampleRecordProcessor())
 	kclProcess.Run()
 }
--- a/decode/decode.go
+++ b/decode/decode.go
@ -0,0 +1,477 @@
+package decode
+
+import (
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/Clever/syslogparser/rfc3164"
+)
+
+// reservedFields are automatically set during decoding.
+// no field written by a user (e.g. contained in the Kayvee JSON) should overwrite them.
+var reservedFields = []string{
+	"prefix",
+	"postfix",
+	"Type",
+}
+
+func stringInSlice(s string, slice []string) bool {
+	for _, item := range slice {
+		if s == item {
+			return true
+		}
+	}
+	return false
+}
+
+// remapSyslog3164Keys renames fields to match our expecations from heka's syslog parser
+// see: https://github.com/mozilla-services/heka/blob/278dd3d5961b9b6e47bb7a912b63ce3faaf8d8bd/sandbox/lua/decoders/rsyslog.lua
+var remapSyslog3164Keys = map[string]string{
+	"hostname":  "hostname",
+	"timestamp": "timestamp",
+	"tag":       "programname",
+	"content":   "rawlog",
+}
+
+// FieldsFromSyslog takes an RSyslog formatted log line and extracts fields from it
+//
+// Supports two log lines formats:
+// - RSYSLOG_TraditionalFileFormat - the "old style" default log file format with low-precision timestamps (RFC3164)
+// - RSYSLOG_FileFormat - a modern-style logfile format similar to TraditionalFileFormat, but with high-precision timestamps and timezone information
+//
+// For more details on Rsylog formats: https://rsyslog-5-8-6-doc.neocities.org/rsyslog_conf_templates.html
+func FieldsFromSyslog(line string) (map[string]interface{}, error) {
+	// rfc3164 includes a severity number in front of the Syslog line, but we don't use that
+	fakeSeverity := "<12>"
+	p3164 := rfc3164.NewParser([]byte(fakeSeverity + line))
+	err := p3164.Parse()
+	if err != nil {
+		return map[string]interface{}{}, err
+	}
+
+	out := map[string]interface{}{}
+	for k, v := range p3164.Dump() {
+		if newKey, ok := remapSyslog3164Keys[k]; ok {
+			out[newKey] = v
+		}
+	}
+	return out, nil
+}
+
+// NonKayveeError occurs when the log line is not Kayvee
+type NonKayveeError struct{}
+
+func (e NonKayveeError) Error() string {
+	return fmt.Sprint("Log line is not Kayvee (doesn't have JSON payload)")
+}
+
+// FieldsFromKayvee takes a log line and extracts fields from the Kayvee (JSON) part
+func FieldsFromKayvee(line string) (map[string]interface{}, error) {
+	m := map[string]interface{}{}
+
+	firstIdx := strings.Index(line, "{")
+	lastIdx := strings.LastIndex(line, "}")
+	if firstIdx == -1 || lastIdx == -1 || firstIdx > lastIdx {
+		return map[string]interface{}{}, &NonKayveeError{}
+	}
+	m["prefix"] = line[:firstIdx]
+	m["postfix"] = line[lastIdx+1:]
+
+	possibleJSON := line[firstIdx : lastIdx+1]
+	var fields map[string]interface{}
+	if err := json.Unmarshal([]byte(possibleJSON), &fields); err != nil {
+		return map[string]interface{}{}, err
+	}
+	for k, v := range fields {
+		if !stringInSlice(k, reservedFields) {
+			m[k] = v
+		}
+	}
+
+	m["type"] = "Kayvee"
+
+	return m, nil
+}
+
+// MetricsRoute represents a metrics kv log route
+type MetricsRoute struct {
+	Series     string
+	Dimensions []string
+	ValueField string
+	RuleName   string
+}
+
+// AnalyticsRoute represents an analytics kv log route
+type AnalyticsRoute struct {
+	Series   string
+	RuleName string
+}
+
+// NotificationRoute represents a notification kv log route
+type NotificationRoute struct {
+	Channel  string
+	Icon     string
+	Message  string
+	User     string
+	RuleName string
+}
+
+// AlertRoute represents an alert kv log route
+type AlertRoute struct {
+	Series     string
+	Dimensions []string
+	StatType   string
+	ValueField string
+	RuleName   string
+}
+
+func getStringValue(json map[string]interface{}, key string) string {
+	val, ok := json[key]
+	if !ok {
+		return ""
+	}
+
+	str, ok := val.(string)
+	if !ok {
+		return ""
+	}
+
+	return str
+}
+
+func getStringArray(json map[string]interface{}, key string) []string {
+	val, ok := json[key]
+	if !ok {
+		return []string{}
+	}
+
+	strArray, ok := val.([]string)
+	if !ok {
+		return []string{}
+	}
+
+	return strArray
+}
+
+// LogRoutes a type alias to make it easier to add route specific filter functions
+type LogRoutes []map[string]interface{}
+
+// MetricsRoutes filters the LogRoutes and returns a list of MetricsRoutes structs
+func (l LogRoutes) MetricsRoutes() []MetricsRoute {
+	routes := []MetricsRoute{}
+
+	for _, route := range l {
+		tipe := getStringValue(route, "type")
+		if tipe != "metrics" {
+			continue
+		}
+
+		series := getStringValue(route, "series")
+		dimensions := getStringArray(route, "dimensions")
+		valueField := getStringValue(route, "value_field")
+		ruleName := getStringValue(route, "rule")
+
+		if series == "" { // TODO: log error
+			continue
+		}
+		if valueField == "" {
+			valueField = "value"
+		}
+
+		routes = append(routes, MetricsRoute{
+			Series:     series,
+			Dimensions: dimensions,
+			ValueField: valueField,
+			RuleName:   ruleName,
+		})
+	}
+
+	return routes
+}
+
+// AnalyticsRoutes filters the LogRoutes and returns a list of AnalyticsRoutes structs
+func (l LogRoutes) AnalyticsRoutes() []AnalyticsRoute {
+	routes := []AnalyticsRoute{}
+
+	for _, route := range l {
+		tipe := getStringValue(route, "type")
+		if tipe != "analytics" {
+			continue
+		}
+
+		series := getStringValue(route, "series")
+		ruleName := getStringValue(route, "rule")
+
+		if series == "" { // TODO: log error
+			continue
+		}
+
+		routes = append(routes, AnalyticsRoute{
+			Series:   series,
+			RuleName: ruleName,
+		})
+	}
+
+	return routes
+}
+
+// NotificationRoutes filters the LogRoutes and returns a list of NotificationRoutes structs
+func (l LogRoutes) NotificationRoutes() []NotificationRoute {
+	routes := []NotificationRoute{}
+
+	for _, route := range l {
+		tipe := getStringValue(route, "type")
+		if tipe != "notifications" {
+			continue
+		}
+
+		channel := getStringValue(route, "channel")
+		icon := getStringValue(route, "icon")
+		message := getStringValue(route, "message")
+		user := getStringValue(route, "user")
+		rule := getStringValue(route, "rule")
+
+		if channel == "" || message == "" { // TODO: log error
+			continue
+		}
+
+		if icon == "" {
+			icon = ":ghost:"
+		}
+		if user == "" {
+			user = "logging-pipeline"
+		}
+
+		routes = append(routes, NotificationRoute{
+			Channel:  channel,
+			Icon:     icon,
+			Message:  message,
+			User:     user,
+			RuleName: rule,
+		})
+	}
+
+	return routes
+}
+
+// AlertRoutes filters the LogRoutes and returns a list of AlertRoutes structs
+func (l LogRoutes) AlertRoutes() []AlertRoute {
+	routes := []AlertRoute{}
+
+	for _, route := range l {
+		tipe := getStringValue(route, "type")
+		if tipe != "alerts" {
+			continue
+		}
+
+		series := getStringValue(route, "series")
+		dimensions := getStringArray(route, "dimensions")
+		statType := getStringValue(route, "stat_type")
+		valueField := getStringValue(route, "value_field")
+		ruleName := getStringValue(route, "rule")
+
+		if series == "" { // TODO: log error
+			continue
+		}
+		if statType == "" {
+			statType = "counter"
+		}
+		if valueField == "" {
+			valueField = "value"
+		}
+
+		routes = append(routes, AlertRoute{
+			Series:     series,
+			Dimensions: dimensions,
+			StatType:   statType,
+			ValueField: valueField,
+			RuleName:   ruleName,
+		})
+	}
+
+	return routes
+}
+
+// KVMeta a struct that represents kv-meta data
+type KVMeta struct {
+	Team     string
+	Version  string
+	Language string
+	Routes   LogRoutes
+}
+
+// ExtractKVMeta returns a struct with available kv-meta data
+func ExtractKVMeta(kvlog map[string]interface{}) KVMeta {
+	tmp, ok := kvlog["_kvmeta"]
+	if !ok {
+		return KVMeta{}
+	}
+
+	kvmeta, ok := tmp.(map[string]interface{})
+	if !ok {
+		return KVMeta{}
+	}
+
+	kvRoutes := []map[string]interface{}{}
+
+	tmp, ok = kvmeta["routes"]
+	if ok {
+		routes, ok := tmp.([]map[string]interface{})
+		if ok {
+			kvRoutes = routes
+		}
+	}
+
+	return KVMeta{
+		Team:     getStringValue(kvmeta, "team"),
+		Version:  getStringValue(kvmeta, "kv_version"),
+		Language: getStringValue(kvmeta, "kv_language"),
+		Routes:   kvRoutes,
+	}
+}
+
+// ParseAndEnhance extracts fields from a log line, and does some post-processing to rename/add fields
+func ParseAndEnhance(line string, env string, stringifyNested bool, renameESReservedFields bool, minimumTimestamp time.Time) (map[string]interface{}, error) {
+	out := map[string]interface{}{}
+
+	syslogFields, err := FieldsFromSyslog(line)
+	if err != nil {
+		return map[string]interface{}{}, err
+	}
+	for k, v := range syslogFields {
+		out[k] = v
+	}
+	rawlog := syslogFields["rawlog"].(string)
+	programname := syslogFields["programname"].(string)
+
+	// Try pulling Kayvee fields out of message
+	kvFields, err := FieldsFromKayvee(rawlog)
+	if err != nil {
+		if _, ok := err.(*NonKayveeError); !ok {
+			return map[string]interface{}{}, err
+		}
+	} else {
+		for k, v := range kvFields {
+			out[k] = v
+		}
+	}
+
+	// Inject additional fields that are useful in log-searching and other business logic
+	out["env"] = env
+
+	// Sometimes its useful to force `container_{env,app,task}`. A specific use-case is writing Docker events.
+	// A separate container monitors for start/stop events, but we set the container values in such a way that
+	// the logs for these events will appear in context for the app that the user is looking at instead of the
+	// docker-events app.
+	forceEnv := ""
+	forceApp := ""
+	forceTask := ""
+	if cEnv, ok := out["container_env"]; ok {
+		forceEnv = cEnv.(string)
+	}
+	if cApp, ok := out["container_app"]; ok {
+		forceApp = cApp.(string)
+	}
+	if cTask, ok := out["container_task"]; ok {
+		forceTask = cTask.(string)
+	}
+	meta, err := getContainerMeta(programname, forceEnv, forceApp, forceTask)
+	if err == nil {
+		for k, v := range meta {
+			out[k] = v
+		}
+	}
+
+	// ES dynamic mappings get finnicky once you start sending nested objects.
+	// E.g., if one app sends a field for the first time as an object, then any log
+	// sent by another app containing that field /not/ as an object will fail.
+	// One solution is to decode nested objects as strings.
+	if stringifyNested {
+		for k, v := range out {
+			_, ismap := v.(map[string]interface{})
+			_, isarr := v.([]interface{})
+			if ismap || isarr {
+				bs, _ := json.Marshal(v)
+				out[k] = string(bs)
+			}
+		}
+	}
+
+	// ES doesn't like fields that start with underscores.
+	if renameESReservedFields {
+		for oldKey, renamedKey := range esFieldRenames {
+			if val, ok := out[oldKey]; ok {
+				out[renamedKey] = val
+				delete(out, oldKey)
+			}
+		}
+	}
+
+	msgTime, ok := out["timestamp"].(time.Time)
+	if ok && !msgTime.After(minimumTimestamp) {
+		return map[string]interface{}{}, fmt.Errorf("message's timestamp < minimumTimestamp")
+	}
+
+	return out, nil
+}
+
+var esFieldRenames = map[string]string{
+	"_index":       "kv__index",
+	"_uid":         "kv__uid",
+	"_type":        "kv__type",
+	"_id":          "kv__id",
+	"_source":      "kv__source",
+	"_size":        "kv__size",
+	"_all":         "kv__all",
+	"_field_names": "kv__field_names",
+	"_timestamp":   "kv__timestamp",
+	"_ttl":         "kv__ttl",
+	"_parent":      "kv__parent",
+	"_routing":     "kv__routing",
+	"_meta":        "kv__meta",
+}
+
+const containerMeta = `([a-z0-9-]+)--([a-z0-9-]+)\/` + // env--app
+	`arn%3Aaws%3Aecs%3Aus-(west|east)-[1-2]%3A[0-9]{12}%3Atask%2F` + // ARN cruft
+	`([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})` // task-id
+
+var containerMetaRegex = regexp.MustCompile(containerMeta)
+
+func getContainerMeta(programname, forceEnv, forceApp, forceTask string) (map[string]string, error) {
+	if programname == "" {
+		return map[string]string{}, fmt.Errorf("no programname")
+	}
+
+	env := ""
+	app := ""
+	task := ""
+	matches := containerMetaRegex.FindAllStringSubmatch(programname, 1)
+	if len(matches) == 1 {
+		env = matches[0][1]
+		app = matches[0][2]
+		task = matches[0][4]
+	}
+
+	if forceEnv != "" {
+		env = forceEnv
+	}
+	if forceApp != "" {
+		app = forceApp
+	}
+	if forceTask != "" {
+		task = forceTask
+	}
+
+	if env == "" || app == "" || task == "" {
+		return map[string]string{}, fmt.Errorf("unable to get one or more of env/app/task")
+	}
+
+	return map[string]string{
+		"container_env":  env,
+		"container_app":  app,
+		"container_task": task,
+	}, nil
+}
--- a/decode/decode_test.go
+++ b/decode/decode_test.go
@ -0,0 +1,834 @@
+package decode
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/Clever/syslogparser"
+	"github.com/stretchr/testify/assert"
+)
+
+const RFC3339Micro = "2006-01-02T15:04:05.999999-07:00"
+
+type Spec struct {
+	Title          string
+	Input          string
+	ExpectedOutput map[string]interface{}
+	ExpectedError  error
+}
+
+func TestKayveeDecoding(t *testing.T) {
+	specs := []Spec{
+		Spec{
+			Title: "handles just JSON",
+			Input: `{"a":"b"}`,
+			ExpectedOutput: map[string]interface{}{
+				"prefix":  "",
+				"postfix": "",
+				"a":       "b",
+				"type":    "Kayvee",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title: "handles prefix + JSON",
+			Input: `prefix {"a":"b"}`,
+			ExpectedOutput: map[string]interface{}{
+				"prefix":  "prefix ",
+				"postfix": "",
+				"a":       "b",
+				"type":    "Kayvee",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title: "handles JSON + postfix",
+			Input: `{"a":"b"} postfix`,
+			ExpectedOutput: map[string]interface{}{
+				"prefix":  "",
+				"postfix": " postfix",
+				"a":       "b",
+				"type":    "Kayvee",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title: "handles prefix + JSON + postfix",
+			Input: `prefix {"a":"b"} postfix`,
+			ExpectedOutput: map[string]interface{}{
+				"prefix":  "prefix ",
+				"postfix": " postfix",
+				"a":       "b",
+				"type":    "Kayvee",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title:          "Returns NonKayveeError if not JSON in body",
+			Input:          `prefix { postfix`,
+			ExpectedOutput: map[string]interface{}{},
+			ExpectedError:  &NonKayveeError{},
+		},
+		Spec{
+			Title:          "errors on invalid JSON (missing a quote)",
+			Input:          `prefix {"a:"b"} postfix`,
+			ExpectedOutput: map[string]interface{}{},
+			ExpectedError:  &json.SyntaxError{},
+		},
+	}
+
+	for _, spec := range specs {
+		t.Run(fmt.Sprintf(spec.Title), func(t *testing.T) {
+			assert := assert.New(t)
+			fields, err := FieldsFromKayvee(spec.Input)
+			if spec.ExpectedError != nil {
+				assert.Error(err)
+				assert.IsType(spec.ExpectedError, err)
+			} else {
+				assert.NoError(err)
+			}
+			assert.Equal(spec.ExpectedOutput, fields)
+		})
+	}
+}
+
+func TestSyslogDecoding(t *testing.T) {
+	// timestamps in Rsyslog_TraditionalFileFormat
+	logTime, err := time.Parse(time.Stamp, "Oct 25 10:20:37")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// parsing assumes log is from the current year
+	logTime = logTime.AddDate(time.Now().Year(), 0, 0).UTC()
+
+	logTime2, err := time.Parse(time.Stamp, "Apr  5 21:45:54")
+	if err != nil {
+		t.Fatal(err)
+	}
+	logTime2 = logTime2.AddDate(time.Now().Year(), 0, 0).UTC()
+
+	// timestamp in Rsyslog_FileFormat
+	logTime3, err := time.Parse(RFC3339Micro, "2017-04-05T21:57:46.794862+00:00")
+	if err != nil {
+		t.Fatal(err)
+	}
+	logTime3 = logTime3.UTC()
+
+	specs := []Spec{
+		Spec{
+			Title: "Parses Rsyslog_TraditionalFileFormat with simple log body",
+			Input: `Oct 25 10:20:37 some-host docker/fa3a5e338a47[1294]: log body`,
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":   logTime,
+				"hostname":    "some-host",
+				"programname": "docker/fa3a5e338a47",
+				"rawlog":      "log body",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title: "Parses Rsyslog_TraditionalFileFormat with haproxy access log body",
+			Input: `Apr  5 21:45:54 influx-service docker/0000aa112233[1234]: [httpd] 2017/04/05 21:45:54 172.17.42.1 - heka [05/Apr/2017:21:45:54 +0000] POST /write?db=foo&precision=ms HTTP/1.1 204 0 - Go 1.1 package http 123456-1234-1234-b11b-000000000000 13.688672ms`,
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":   logTime2,
+				"hostname":    "influx-service",
+				"programname": "docker/0000aa112233",
+				"rawlog":      "[httpd] 2017/04/05 21:45:54 172.17.42.1 - heka [05/Apr/2017:21:45:54 +0000] POST /write?db=foo&precision=ms HTTP/1.1 204 0 - Go 1.1 package http 123456-1234-1234-b11b-000000000000 13.688672ms",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title: "Parses Rsyslog_TraditionalFileFormat",
+			Input: `Apr  5 21:45:54 mongodb-some-machine whackanop: 2017/04/05 21:46:11 found 0 ops`,
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":   logTime2,
+				"hostname":    "mongodb-some-machine",
+				"programname": "whackanop",
+				"rawlog":      "2017/04/05 21:46:11 found 0 ops",
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title: "Parses Rsyslog_ FileFormat with Kayvee payload",
+			Input: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished"}`,
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":   logTime3,
+				"hostname":    "ip-10-0-0-0",
+				"programname": `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":      `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished"}`,
+			},
+			ExpectedError: nil,
+		},
+		Spec{
+			Title:          "Fails to parse non-RSyslog log line",
+			Input:          `not rsyslog`,
+			ExpectedOutput: map[string]interface{}{},
+			ExpectedError:  &syslogparser.ParserError{},
+		},
+	}
+	for _, spec := range specs {
+		t.Run(fmt.Sprintf(spec.Title), func(t *testing.T) {
+			assert := assert.New(t)
+			fields, err := FieldsFromSyslog(spec.Input)
+			if spec.ExpectedError != nil {
+				assert.Error(err)
+				assert.IsType(spec.ExpectedError, err)
+			} else {
+				assert.NoError(err)
+			}
+			assert.Equal(spec.ExpectedOutput, fields)
+		})
+	}
+}
+
+type ParseAndEnhanceInput struct {
+	Line                   string
+	StringifyNested        bool
+	RenameESReservedFields bool
+	MinimumTimestamp       time.Time
+}
+
+type ParseAndEnhanceSpec struct {
+	Title          string
+	Input          ParseAndEnhanceInput
+	ExpectedOutput map[string]interface{}
+	ExpectedError  error
+}
+
+func TestParseAndEnhance(t *testing.T) {
+	// timestamp in Rsyslog_FileFormat
+	logTime3, err := time.Parse(RFC3339Micro, "2017-04-05T21:57:46.794862+00:00")
+	if err != nil {
+		t.Fatal(err)
+	}
+	logTime3 = logTime3.UTC()
+
+	specs := []ParseAndEnhanceSpec{
+		ParseAndEnhanceSpec{
+			Title: "Parses a Kayvee log line from an ECS app",
+			Input: ParseAndEnhanceInput{Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished"}`},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished"}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Parses a Kayvee log line from an ECS app, with override to container_app",
+			Input: ParseAndEnhanceInput{Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished","container_app":"force-app"}`},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished","container_app":"force-app"}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "force-app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Parses a non-Kayvee log line",
+			Input: ParseAndEnhanceInput{Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: some log`},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `some log`,
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title:          "Fails to parse non-RSyslog log line",
+			Input:          ParseAndEnhanceInput{Line: `not rsyslog`},
+			ExpectedOutput: map[string]interface{}{},
+			ExpectedError:  &syslogparser.ParserError{},
+		},
+		ParseAndEnhanceSpec{
+			Title: "Parses JSON values",
+			Input: ParseAndEnhanceInput{Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "nested": {"a":"b"}}`},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "nested": {"a":"b"}}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+				"nested":         map[string]interface{}{"a": "b"},
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Has the option to stringify object values",
+			Input: ParseAndEnhanceInput{
+				Line:            `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "nested": {"a":"b"}}`,
+				StringifyNested: true,
+			},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "nested": {"a":"b"}}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+				"nested":         `{"a":"b"}`,
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Has the option to stringify array values",
+			Input: ParseAndEnhanceInput{
+				Line:            `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "nested": [{"a":"b"}]}`,
+				StringifyNested: true,
+			},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "nested": [{"a":"b"}]}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+				"nested":         `[{"a":"b"}]`,
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Has the option to rename reserved ES fields",
+			Input: ParseAndEnhanceInput{
+				Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				RenameESReservedFields: true,
+			},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+				"kv__source":     "a",
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Errors if logTime < MinimumTimestamp",
+			Input: ParseAndEnhanceInput{
+				Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				RenameESReservedFields: true,
+				MinimumTimestamp:       time.Now().Add(100 * time.Hour * 24 * 365), // good thru year 2117
+			},
+			ExpectedOutput: map[string]interface{}{},
+			ExpectedError:  fmt.Errorf(""),
+		},
+		ParseAndEnhanceSpec{
+			Title: "Accepts logs if logTime > MinimumTimestamp",
+			Input: ParseAndEnhanceInput{
+				Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				RenameESReservedFields: true,
+				MinimumTimestamp:       time.Now().Add(-100 * time.Hour * 24 * 365), // good thru year 2117
+			},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+				"kv__source":     "a",
+			},
+			ExpectedError: nil,
+		},
+		ParseAndEnhanceSpec{
+			Title: "Accepts logs if logTime > MinimumTimestamp",
+			Input: ParseAndEnhanceInput{
+				Line: `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				RenameESReservedFields: true,
+				MinimumTimestamp:       time.Now().Add(-100 * time.Hour * 24 * 365), // good thru year 2117
+			},
+			ExpectedOutput: map[string]interface{}{
+				"timestamp":      logTime3,
+				"hostname":       "ip-10-0-0-0",
+				"programname":    `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`,
+				"rawlog":         `2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished", "_source": "a"}`,
+				"title":          "request_finished",
+				"type":           "Kayvee",
+				"prefix":         "2017/04/05 21:57:46 some_file.go:10: ",
+				"postfix":        "",
+				"env":            "deploy-env",
+				"container_env":  "env",
+				"container_app":  "app",
+				"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+				"kv__source":     "a",
+			},
+			ExpectedError: nil,
+		},
+	}
+	for _, spec := range specs {
+		t.Run(fmt.Sprintf(spec.Title), func(t *testing.T) {
+			assert := assert.New(t)
+			fields, err := ParseAndEnhance(spec.Input.Line, "deploy-env", spec.Input.StringifyNested, spec.Input.RenameESReservedFields, spec.Input.MinimumTimestamp)
+			if spec.ExpectedError != nil {
+				assert.Error(err)
+				assert.IsType(spec.ExpectedError, err)
+			} else {
+				assert.NoError(err)
+			}
+			assert.Equal(spec.ExpectedOutput, fields)
+		})
+	}
+}
+
+func TestGetContainerMeta(t *testing.T) {
+	assert := assert.New(t)
+
+	t.Log("Must have a programname to get container meta")
+	programname := ""
+	_, err := getContainerMeta(programname, "", "", "")
+	assert.Error(err)
+
+	t.Log("Can parse a programname")
+	programname = `env1--app2/arn%3Aaws%3Aecs%3Aus-west-1%3A589690932525%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`
+	meta, err := getContainerMeta(programname, "", "", "")
+	assert.NoError(err)
+	assert.Equal(map[string]string{
+		"container_env":  "env1",
+		"container_app":  "app2",
+		"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+	}, meta)
+
+	t.Log("Can override just 'env'")
+	overrideEnv := "force-env"
+	meta, err = getContainerMeta(programname, overrideEnv, "", "")
+	assert.NoError(err)
+	assert.Equal(map[string]string{
+		"container_env":  overrideEnv,
+		"container_app":  "app2",
+		"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+	}, meta)
+
+	t.Log("Can override just 'app'")
+	overrideApp := "force-app"
+	meta, err = getContainerMeta(programname, "", overrideApp, "")
+	assert.NoError(err)
+	assert.Equal(map[string]string{
+		"container_env":  "env1",
+		"container_app":  overrideApp,
+		"container_task": "abcd1234-1a3b-1a3b-1234-d76552f4b7ef",
+	}, meta)
+
+	t.Log("Can override just 'task'")
+	overrideTask := "force-task"
+	meta, err = getContainerMeta(programname, "", "", overrideTask)
+	assert.NoError(err)
+	assert.Equal(map[string]string{
+		"container_env":  "env1",
+		"container_app":  "app2",
+		"container_task": overrideTask,
+	}, meta)
+
+	t.Log("Can override all fields")
+	programname = `env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef`
+	meta, err = getContainerMeta(programname, overrideEnv, overrideApp, overrideTask)
+	assert.NoError(err)
+	assert.Equal(map[string]string{
+		"container_env":  overrideEnv,
+		"container_app":  overrideApp,
+		"container_task": overrideTask,
+	}, meta)
+}
+
+func TestExtractKVMeta(t *testing.T) {
+	assert := assert.New(t)
+
+	tests := []struct {
+		Description                string
+		Log                        map[string]interface{}
+		Team                       string
+		Language                   string
+		Version                    string
+		ExpectedMetricsRoutes      []MetricsRoute
+		ExpectedAnalyticsRoutes    []AnalyticsRoute
+		ExpectedNotificationRoutes []NotificationRoute
+		ExpectedAlertRoutes        []AlertRoute
+	}{
+		{
+			Description: "log line with no routes",
+			Log:         map[string]interface{}{"hi": "hello!"},
+		},
+		{
+			Description: "empty _kvmeta",
+			Log: map[string]interface{}{
+				"hi":      "hello!",
+				"_kvmeta": map[string]interface{}{},
+			},
+		},
+		{
+			Description: "_kvmeta with no routes",
+			Team:        "green",
+			Version:     "three",
+			Language:    "tree",
+			Log: map[string]interface{}{
+				"hi": "hello!",
+				"_kvmeta": map[string]interface{}{
+					"team":        "green",
+					"kv_version":  "three",
+					"kv_language": "tree",
+				},
+			},
+		},
+		{
+			Description: "_kvmeta with metric routes",
+			Team:        "green",
+			Version:     "three",
+			Language:    "tree",
+			ExpectedMetricsRoutes: []MetricsRoute{
+				{
+					Series:     "1,1,2,3,5,8,13",
+					Dimensions: []string{"app", "district"},
+					ValueField: "value",
+					RuleName:   "cool",
+				},
+				{
+					Series:     "1,1,2,6,24,120,720,5040",
+					Dimensions: []string{"app", "district"},
+					ValueField: "value",
+					RuleName:   "cool2",
+				},
+			},
+			Log: map[string]interface{}{
+				"hi": "hello!",
+				"_kvmeta": map[string]interface{}{
+					"team":        "green",
+					"kv_version":  "three",
+					"kv_language": "tree",
+					"routes": []map[string]interface{}{
+						map[string]interface{}{
+							"type":        "metrics",
+							"rule":        "cool",
+							"series":      "1,1,2,3,5,8,13",
+							"value_field": "value",
+							"dimensions":  []string{"app", "district"},
+						},
+						map[string]interface{}{
+							"type":       "metrics",
+							"rule":       "cool2",
+							"series":     "1,1,2,6,24,120,720,5040",
+							"dimensions": []string{"app", "district"},
+						},
+					},
+				},
+			},
+		},
+		{
+			Description: "_kvmeta with analytic routes",
+			Team:        "green",
+			Version:     "christmas",
+			Language:    "tree",
+			ExpectedAnalyticsRoutes: []AnalyticsRoute{
+				{
+					Series:   "what-is-this",
+					RuleName: "what's-this?",
+				},
+				{
+					RuleName: "there's-app-invites-everywhere",
+					Series:   "there's-bts-in-the-air",
+				},
+			},
+			Log: map[string]interface{}{
+				"hi": "hello!",
+				"_kvmeta": map[string]interface{}{
+					"team":        "green",
+					"kv_version":  "christmas",
+					"kv_language": "tree",
+					"routes": []map[string]interface{}{
+						map[string]interface{}{
+							"type":   "analytics",
+							"rule":   "what's-this?",
+							"series": "what-is-this",
+						},
+						map[string]interface{}{
+							"type":   "analytics",
+							"rule":   "there's-app-invites-everywhere",
+							"series": "there's-bts-in-the-air",
+						},
+					},
+				},
+			},
+		},
+		{
+			Description: "_kvmeta with notification routes",
+			Team:        "slack",
+			Version:     "evergreen",
+			Language:    "markdown-ish",
+			ExpectedNotificationRoutes: []NotificationRoute{
+				{
+					RuleName: "did-you-know",
+					Channel:  "originally-slack",
+					Message:  "was a gaming company",
+					Icon:     ":video_game:",
+					User:     "og slack bronie",
+				},
+				{
+					RuleName: "what's-the-catch",
+					Channel:  "slack-is-built-with-php",
+					Message:  "just like farmville",
+					Icon:     ":ghost:",
+					User:     "logging-pipeline",
+				},
+			},
+			Log: map[string]interface{}{
+				"hi": "hello!",
+				"_kvmeta": map[string]interface{}{
+					"team":        "slack",
+					"kv_version":  "evergreen",
+					"kv_language": "markdown-ish",
+					"routes": []map[string]interface{}{
+						map[string]interface{}{
+							"type":    "notifications",
+							"rule":    "did-you-know",
+							"channel": "originally-slack",
+							"message": "was a gaming company",
+							"icon":    ":video_game:",
+							"user":    "og slack bronie",
+						},
+						map[string]interface{}{
+							"type":    "notifications",
+							"rule":    "what's-the-catch",
+							"channel": "slack-is-built-with-php",
+							"message": "just like farmville",
+						},
+					},
+				},
+			},
+		},
+		{
+			Description: "_kvmeta with alert routes",
+			Team:        "a-team",
+			Version:     "old",
+			Language:    "jive",
+			ExpectedAlertRoutes: []AlertRoute{
+				{
+					RuleName:   "last-call",
+					Series:     "doing-it-til-we-fall",
+					Dimensions: []string{"who", "where"},
+					StatType:   "guage",
+					ValueField: "status",
+				},
+				{
+					RuleName:   "watch-out-now",
+					Series:     "dem-gators-gonna-bite-ya",
+					Dimensions: []string{"how-fresh", "how-clean"},
+					StatType:   "counter",
+					ValueField: "value",
+				},
+			},
+			Log: map[string]interface{}{
+				"hi": "hello!",
+				"_kvmeta": map[string]interface{}{
+					"team":        "a-team",
+					"kv_version":  "old",
+					"kv_language": "jive",
+					"routes": []map[string]interface{}{
+						map[string]interface{}{
+							"type":        "alerts",
+							"rule":        "last-call",
+							"series":      "doing-it-til-we-fall",
+							"dimensions":  []string{"who", "where"},
+							"stat_type":   "guage",
+							"value_field": "status",
+						},
+						map[string]interface{}{
+							"type":       "alerts",
+							"rule":       "watch-out-now",
+							"series":     "dem-gators-gonna-bite-ya",
+							"dimensions": []string{"how-fresh", "how-clean"},
+						},
+					},
+				},
+			},
+		},
+		{
+			Description: "_kvmeta with all types of routes",
+			Team:        "diversity",
+			Version:     "kv-routes",
+			Language:    "understanding",
+			ExpectedMetricsRoutes: []MetricsRoute{
+				{
+					RuleName:   "all-combos",
+					Series:     "1,1,2,6,24,120,720,5040",
+					Dimensions: []string{"fact", "orial"},
+					ValueField: "value",
+				},
+			},
+			ExpectedAnalyticsRoutes: []AnalyticsRoute{
+				{
+					RuleName: "there's-app-invites-everywhere",
+					Series:   "there's-bts-in-the-air",
+				},
+			},
+			ExpectedNotificationRoutes: []NotificationRoute{
+				{
+					RuleName: "what's-the-catch",
+					Channel:  "slack-is-built-with-php",
+					Message:  "just like farmville",
+					Icon:     ":ghost:",
+					User:     "logging-pipeline",
+				},
+			},
+			ExpectedAlertRoutes: []AlertRoute{
+				{
+					RuleName:   "last-call",
+					Series:     "doing-it-til-we-fall",
+					Dimensions: []string{"who", "where"},
+					StatType:   "guage",
+					ValueField: "status",
+				},
+			},
+			Log: map[string]interface{}{
+				"hi": "hello!",
+				"_kvmeta": map[string]interface{}{
+					"team":        "diversity",
+					"kv_version":  "kv-routes",
+					"kv_language": "understanding",
+					"routes": []map[string]interface{}{
+						map[string]interface{}{
+							"type":       "metrics",
+							"rule":       "all-combos",
+							"series":     "1,1,2,6,24,120,720,5040",
+							"dimensions": []string{"fact", "orial"},
+						},
+						map[string]interface{}{
+							"type":   "analytics",
+							"rule":   "there's-app-invites-everywhere",
+							"series": "there's-bts-in-the-air",
+						},
+						map[string]interface{}{
+							"type":    "notifications",
+							"rule":    "what's-the-catch",
+							"channel": "slack-is-built-with-php",
+							"message": "just like farmville",
+						},
+						map[string]interface{}{
+							"type":        "alerts",
+							"rule":        "last-call",
+							"series":      "doing-it-til-we-fall",
+							"dimensions":  []string{"who", "where"},
+							"stat_type":   "guage",
+							"value_field": "status",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Log(test.Description)
+		kvmeta := ExtractKVMeta(test.Log)
+
+		assert.Equal(test.Team, kvmeta.Team)
+		assert.Equal(test.Language, kvmeta.Language)
+		assert.Equal(test.Version, kvmeta.Version)
+
+		assert.Equal(len(test.ExpectedMetricsRoutes), len(kvmeta.Routes.MetricsRoutes()))
+		for idx, route := range kvmeta.Routes.MetricsRoutes() {
+			expected := test.ExpectedMetricsRoutes[idx]
+			assert.Exactly(expected, route)
+		}
+		assert.Equal(len(test.ExpectedAnalyticsRoutes), len(kvmeta.Routes.AnalyticsRoutes()))
+		for idx, route := range kvmeta.Routes.AnalyticsRoutes() {
+			expected := test.ExpectedAnalyticsRoutes[idx]
+			assert.Exactly(expected, route)
+		}
+		assert.Equal(len(test.ExpectedNotificationRoutes), len(kvmeta.Routes.NotificationRoutes()))
+		for idx, route := range kvmeta.Routes.NotificationRoutes() {
+			expected := test.ExpectedNotificationRoutes[idx]
+			assert.Exactly(expected, route)
+		}
+		assert.Equal(len(test.ExpectedAlertRoutes), len(kvmeta.Routes.AlertRoutes()))
+		for idx, route := range kvmeta.Routes.AlertRoutes() {
+			expected := test.ExpectedAlertRoutes[idx]
+			assert.Exactly(expected, route)
+		}
+	}
+}
+
+// Benchmarks
+const benchmarkLine = `2017-04-05T21:57:46.794862+00:00 ip-10-0-0-0 env--app/arn%3Aaws%3Aecs%3Aus-west-1%3A999988887777%3Atask%2Fabcd1234-1a3b-1a3b-1234-d76552f4b7ef[3291]: 2017/04/05 21:57:46 some_file.go:10: {"title":"request_finished"}`
+
+func BenchmarkFieldsFromKayvee(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		_, err := FieldsFromKayvee(benchmarkLine)
+		if err != nil {
+			b.FailNow()
+		}
+	}
+}
+
+func BenchmarkFieldsFromSyslog(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		_, err := FieldsFromSyslog(benchmarkLine)
+		if err != nil {
+			b.FailNow()
+		}
+	}
+}
+
+func BenchmarkParseAndEnhance(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		_, err := ParseAndEnhance(benchmarkLine, "env", false, false, time.Time{})
+		if err != nil {
+			b.FailNow()
+		}
+	}
+}
--- a/glide.lock
+++ b/glide.lock
@ -0,0 +1,53 @@
+hash: 6da9731518797a7e339144f126af589f72f860bee154b0f2a552f91d2bc01bab
+updated: 2017-07-18T02:00:59.747262097Z
+imports:
+- name: github.com/aws/aws-sdk-go
+  version: b73b028e599fa9176687c70b8f9cafbe57c27d20
+  subpackages:
+  - aws
+  - aws/session
+  - service/firehose
+- name: github.com/Clever/kinesis-to-firehose
+  version: dca69c87e1662c7b1f55581399544d05fdcb09ab
+  subpackages:
+  - writer
+- name: github.com/Clever/syslogparser
+  version: 93ab95f7ff16c9ef1f2d09bc37c0a0c31bad98ea
+  subpackages:
+  - rfc3164
+- name: github.com/jeromer/syslogparser
+  version: 0e4ae46ea3f08de351074b643d649d5d00661a3c
+- name: github.com/xeipuuv/gojsonpointer
+  version: e0fe6f68307607d540ed8eac07a342c33fa1b54a
+- name: github.com/xeipuuv/gojsonreference
+  version: e02fc20de94c78484cd5ffb007f8af96be030a45
+- name: github.com/xeipuuv/gojsonschema
+  version: e18f0065e8c148fcf567ac43a3f8f5b66ac0720b
+- name: golang.org/x/net
+  version: a6577fac2d73be281a500b310739095313165611
+  subpackages:
+  - context
+- name: golang.org/x/time
+  version: f51c12702a4d776e4c1fa9b0fabab841babae631
+  subpackages:
+  - rate
+- name: gopkg.in/Clever/kayvee-go.v6
+  version: 096364e316a52652d3493be702d8105d8d01db84
+  subpackages:
+  - logger
+  - router
+- name: gopkg.in/yaml.v2
+  version: a5b47d31c556af34a302ce5d659e6fea44d90de0
+testImports:
+- name: github.com/davecgh/go-spew
+  version: 6d212800a42e8ab5c146b8ace3490ee17e5225f9
+  subpackages:
+  - spew
+- name: github.com/pmezard/go-difflib
+  version: d8ed2627bdf02c080bf22230dbb337003b7aba2d
+  subpackages:
+  - difflib
+- name: github.com/stretchr/testify
+  version: 69483b4bd14f5845b5a1e55bca19e954e827f1d0
+  subpackages:
+  - assert
--- a/glide.yaml
+++ b/glide.yaml
@ -0,0 +1,22 @@
+package: github.com/Clever/amazon-kinesis-client-go
+import:
+- package: github.com/Clever/kinesis-to-firehose
+  subpackages:
+  - writer
+- package: github.com/Clever/syslogparser
+  subpackages:
+  - rfc3164
+- package: github.com/aws/aws-sdk-go
+  subpackages:
+  - aws
+  - aws/session
+  - service/firehose
+- package: golang.org/x/time
+  subpackages:
+  - rate
+testImport:
+- package: github.com/stretchr/testify
+  subpackages:
+  - assert
+- package: gopkg.in/Clever/kayvee-go.v6
+  version: ^6.0.0
--- a/golang.mk
+++ b/golang.mk
@ -0,0 +1,142 @@
+# This is the default Clever Golang Makefile.
+# It is stored in the dev-handbook repo, github.com/Clever/dev-handbook
+# Please do not alter this file directly.
+GOLANG_MK_VERSION := 0.1.4
+
+SHELL := /bin/bash
+.PHONY: golang-godep-vendor golang-test-deps $(GODEP)
+
+# if the gopath includes several directories, use only the first
+GOPATH=$(shell echo $$GOPATH | cut -d: -f1)
+
+# This block checks and confirms that the proper Go toolchain version is installed.
+# arg1: golang version
+define golang-version-check
+GOVERSION := $(shell go version | grep $(1))
+_ := $(if \
+	$(shell go version | grep $(1)), \
+	@echo "", \
+	$(error "must be running Go version $(1)"))
+endef
+
+export GO15VENDOREXPERIMENT=1
+
+# FGT is a utility that exits with 1 whenever any stderr/stdout output is recieved.
+FGT := $(GOPATH)/bin/fgt
+$(FGT):
+	go get github.com/GeertJohan/fgt
+
+# Godep is a tool used to manage Golang dependencies in the style of the Go 1.5
+# vendoring experiment.
+GODEP := $(GOPATH)/bin/godep
+$(GODEP):
+	go get -u github.com/tools/godep
+
+# Golint is a tool for linting Golang code for common errors.
+GOLINT := $(GOPATH)/bin/golint
+$(GOLINT):
+	go get github.com/golang/lint/golint
+
+# golang-vendor-deps installs all dependencies needed for different test cases.
+golang-godep-vendor-deps: $(GODEP)
+
+# golang-godep-vendor is a target for saving dependencies with the godep tool
+# to the vendor/ directory. All nested vendor/ directories are deleted as they
+# are not handled well by the Go toolchain.
+# arg1: pkg path
+define golang-godep-vendor
+$(GODEP) save $(1)
+@# remove any nested vendor directories
+find vendor/ -path '*/vendor' -type d | xargs -IX rm -r X
+endef
+
+# golang-fmt-deps requires the FGT tool for checking output
+golang-fmt-deps: $(FGT)
+
+# golang-fmt checks that all golang files in the pkg are formatted correctly.
+# arg1: pkg path
+define golang-fmt
+@echo "FORMATTING $(1)..."
+@$(FGT) gofmt -l=true $(GOPATH)/src/$(1)/*.go
+endef
+
+# golang-lint-deps requires the golint tool for golang linting.
+golang-lint-deps: $(GOLINT)
+
+# golang-lint calls golint on all golang files in the pkg.
+# arg1: pkg path
+define golang-lint
+@echo "LINTING $(1)..."
+@find $(GOPATH)/src/$(1)/*.go -type f | grep -v gen_ | xargs $(GOLINT)
+endef
+
+# golang-lint-deps-strict requires the golint tool for golang linting.
+golang-lint-deps-strict: $(GOLINT) $(FGT)
+
+# golang-lint-strict calls golint on all golang files in the pkg and fails if any lint
+# errors are found.
+# arg1: pkg path
+define golang-lint-strict
+@echo "LINTING $(1)..."
+@find $(GOPATH)/src/$(1)/*.go -type f | grep -v gen_ | xargs $(FGT) $(GOLINT)
+endef
+
+# golang-test-deps is here for consistency
+golang-test-deps:
+
+# golang-test uses the Go toolchain to run all tests in the pkg.
+# arg1: pkg path
+define golang-test
+@echo "TESTING $(1)..."
+@go test -v $(1)
+endef
+
+# golang-test-strict-deps is here for consistency
+golang-test-strict-deps:
+
+# golang-test-strict uses the Go toolchain to run all tests in the pkg with the race flag
+# arg1: pkg path
+define golang-test-strict
+@echo "TESTING $(1)..."
+@go test -v -race $(1)
+endef
+
+# golang-vet-deps is here for consistency
+golang-vet-deps:
+
+# golang-vet uses the Go toolchain to vet all the pkg for common mistakes.
+# arg1: pkg path
+define golang-vet
+@echo "VETTING $(1)..."
+@go vet $(GOPATH)/src/$(1)/*.go
+endef
+
+# golang-test-all-deps installs all dependencies needed for different test cases.
+golang-test-all-deps: golang-fmt-deps golang-lint-deps golang-test-deps golang-vet-deps
+
+# golang-test-all calls fmt, lint, vet and test on the specified pkg.
+# arg1: pkg path
+define golang-test-all
+$(call golang-fmt,$(1))
+$(call golang-lint,$(1))
+$(call golang-vet,$(1))
+$(call golang-test,$(1))
+endef
+
+# golang-test-all-strict-deps: installs all dependencies needed for different test cases.
+golang-test-all-strict-deps: golang-fmt-deps golang-lint-deps-strict golang-test-strict-deps golang-vet-deps
+
+# golang-test-all-strict calls fmt, lint, vet and test on the specified pkg with strict
+# requirements that no errors are thrown while linting.
+# arg1: pkg path
+define golang-test-all-strict
+$(call golang-fmt,$(1))
+$(call golang-lint-strict,$(1))
+$(call golang-vet,$(1))
+$(call golang-test-strict,$(1))
+endef
+
+# golang-update-makefile downloads latest version of golang.mk
+golang-update-makefile:
+	@wget https://raw.githubusercontent.com/Clever/dev-handbook/master/make/golang.mk -O /tmp/golang.mk 2>/dev/null
+	@if ! grep -q $(GOLANG_MK_VERSION) /tmp/golang.mk; then cp /tmp/golang.mk golang.mk && echo "golang.mk updated"; else echo "golang.mk is up-to-date"; fi
--- a/kcl/kcl.go
+++ b/kcl/kcl.go
@ -12,11 +12,17 @@ import (
 )

 type RecordProcessor interface {
-	Initialize(shardID string, checkpointer *Checkpointer) error
+	Initialize(shardID string, checkpointer Checkpointer) error
 	ProcessRecords(records []Record) error
 	Shutdown(reason string) error
 }

+type Checkpointer interface {
+	Checkpoint(sequenceNumber *string, subSequenceNumber *int) error
+	CheckpointWithRetry(sequenceNumber *string, subSequenceNumber *int, retryCount int) error
+	Shutdown()
+}
+
 type CheckpointError struct {
 	e string
 }
@ -25,13 +31,13 @@ func (ce CheckpointError) Error() string {
 	return ce.e
 }

-type Checkpointer struct {
+type checkpointer struct {
 	mux sync.Mutex

 	ioHandler ioHandler
 }

-func (c *Checkpointer) getAction() (interface{}, error) {
+func (c *checkpointer) getAction() (interface{}, error) {
 	line, err := c.ioHandler.readLine()
 	if err != nil {
 		return nil, err
@ -43,7 +49,7 @@ func (c *Checkpointer) getAction() (interface{}, error) {
 	return action, nil
 }

-func (c *Checkpointer) Checkpoint(sequenceNumber *string, subSequenceNumber *int) error {
+func (c *checkpointer) Checkpoint(sequenceNumber *string, subSequenceNumber *int) error {
 	c.mux.Lock()
 	defer c.mux.Unlock()

@ -74,7 +80,7 @@ func (c *Checkpointer) Checkpoint(sequenceNumber *string, subSequenceNumber *int

 // CheckpointWithRetry tries to save a checkPoint up to `retryCount` + 1 times.
 // `retryCount` should be >= 0
-func (c *Checkpointer) CheckpointWithRetry(
+func (c *checkpointer) CheckpointWithRetry(
 	sequenceNumber *string, subSequenceNumber *int, retryCount int,
 ) error {
 	sleepDuration := 5 * time.Second
@ -108,7 +114,7 @@ func (c *Checkpointer) CheckpointWithRetry(
 	return nil
 }

-func (c *Checkpointer) Shutdown() {
+func (c *checkpointer) Shutdown() {
 	c.CheckpointWithRetry(nil, nil, 5)
 }

@ -225,7 +231,7 @@ func New(inputFile io.Reader, outputFile, errorFile io.Writer, recordProcessor R
 	}
 	return &KCLProcess{
 		ioHandler: i,
-		checkpointer: &Checkpointer{
+		checkpointer: &checkpointer{
 			ioHandler: i,
 		},
 		recordProcessor: recordProcessor,
@ -234,7 +240,7 @@ func New(inputFile io.Reader, outputFile, errorFile io.Writer, recordProcessor R

 type KCLProcess struct {
 	ioHandler       ioHandler
-	checkpointer    *Checkpointer
+	checkpointer    Checkpointer
 	recordProcessor RecordProcessor
 }

@ -278,11 +284,17 @@ func (kclp *KCLProcess) Run() {
 	for {
 		line, err := kclp.ioHandler.readLine()
 		if err != nil {
-			kclp.ioHandler.writeError(err.Error())
+			kclp.ioHandler.writeError("Read line error: " + err.Error())
 			return
 		} else if line == nil {
-			break
+			kclp.ioHandler.writeError("Empty read line recieved")
+			return
+		}
+
+		err = kclp.handleLine(line.String())
+		if err != nil {
+			kclp.ioHandler.writeError("Handle line error: " + err.Error())
+			return
 		}
-		kclp.handleLine(line.String())
 	}
 }
--- a/splitter/README.md
+++ b/splitter/README.md
@ -0,0 +1,10 @@
+splitter
+===
+
+This splitter allows ingesting logs from a CWLogs subscription.
+
+Splitter's expected input is batched logs from a CloudWatchLogs subscription to a Kinesis Stream.
+The CWLogs subscription has a special format which bundles several logs into a single record.
+The splitter takes this record and splits it into multiple logs.
+These logs are also modified to mimic the RSyslog format we expect from our other logs.
+This allows them to be decoded normally by the rest of the pipeline.
--- a/splitter/splitter.go
+++ b/splitter/splitter.go
@ -0,0 +1,113 @@
+package splitter
+
+import (
+	"bytes"
+	"compress/gzip"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"regexp"
+	"time"
+)
+
+// LogEvent is a single log line within a LogEventBatch
+type LogEvent struct {
+	ID        string `json:"id"`
+	Timestamp int64  `json:"timestamp"`
+	Message   string `json:"message"`
+}
+
+// LogEventBatch is a batch of multiple log lines, read from a KinesisStream with a CWLogs subscription
+type LogEventBatch struct {
+	MessageType         string     `json:"messageType"`
+	Owner               string     `json:"owner"`
+	LogGroup            string     `json:"logGroup"`
+	LogStream           string     `json:"logStream"`
+	SubscriptionFilters []string   `json:"subscriptionFilters"`
+	LogEvents           []LogEvent `json:"logEvents"`
+}
+
+// IsGzipped returns whether or not a string is Gzipped (determined by looking for a Gzip byte prefix)
+func IsGzipped(b []byte) bool {
+	return b[0] == 0x1f && b[1] == 0x8b
+}
+
+// GetMessagesFromGzippedInput takes a gzipped record from a CWLogs Subscription and splits it into
+// a slice of messages.
+func GetMessagesFromGzippedInput(input []byte, prodEnv bool) ([][]byte, error) {
+	unpacked, err := unpack(input)
+	if err != nil {
+		return [][]byte{}, err
+	}
+	return Split(unpacked, prodEnv), nil
+}
+
+// Unpack expects a gzipped + json-stringified LogEventBatch
+func unpack(input []byte) (LogEventBatch, error) {
+	gzipReader, err := gzip.NewReader(bytes.NewReader(input))
+	if err != nil {
+		return LogEventBatch{}, err
+	}
+
+	byt, err := ioutil.ReadAll(gzipReader)
+	if err != nil {
+		return LogEventBatch{}, err
+	}
+
+	var dat LogEventBatch
+	if err := json.Unmarshal(byt, &dat); err != nil {
+		return LogEventBatch{}, err
+	}
+
+	return dat, nil
+}
+
+// RFC3339Micro is the RFC3339 format in microseconds
+const RFC3339Micro = "2006-01-02T15:04:05.999999-07:00"
+
+const taskMeta = `([a-z0-9-]+)--([a-z0-9-]+)\/` + // env--app
+	`([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})\/` + // task-id
+	`([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})` // container-id
+
+var taskRegex = regexp.MustCompile(taskMeta)
+
+// Split takes a LogEventBatch and separates into a slice of enriched log lines
+// Lines are enhanced by adding an Rsyslog prefix, which should be handled correctly by
+// the subsequent decoding logic.
+func Split(b LogEventBatch, prodEnv bool) [][]byte {
+	env := "unknown"
+	app := "unknown"
+	task := "00001111-2222-3333-4444-555566667777"
+	matches := taskRegex.FindAllStringSubmatch(b.LogStream, 1)
+	if len(matches) == 1 {
+		env = matches[0][1]
+		app = matches[0][2]
+		task = matches[0][3]
+	}
+
+	if (env == "production") != prodEnv {
+		// if there's a mis-match between the consumer's environment and the log's environment,
+		// throw away the log. (this is a workaround for coarse grained subscription filters.)
+		return [][]byte{}
+	}
+
+	rsyslogPrefix := `%s %s %s[%d]: %s`
+	// programName is a mocked ARN in the format expected by our log decoders
+	programName := env + "--" + app + `/arn%3Aaws%3Aecs%3Aus-east-1%3A999988887777%3Atask%2F` + task
+	mockPid := 1
+	hostname := "aws-batch"
+
+	out := [][]byte{}
+	for _, event := range b.LogEvents {
+		// Adding an extra Microsecond forces `Format` to include all 6 digits within the micorsecond format.
+		// Otherwise, time.Format omits trailing zeroes. (https://github.com/golang/go/issues/12472)
+		nsecs := event.Timestamp*int64(time.Millisecond) + int64(time.Microsecond)
+		logTime := time.Unix(0, nsecs).UTC().Format(RFC3339Micro)
+
+		// Fake an RSyslog prefix, expected by consumers
+		formatted := fmt.Sprintf(rsyslogPrefix, logTime, hostname, programName, mockPid, event.Message)
+		out = append(out, []byte(formatted))
+	}
+
+	return out
+}
--- a/splitter/splitter_test.go
+++ b/splitter/splitter_test.go
@ -0,0 +1,182 @@
+package splitter
+
+import (
+	"bytes"
+	"compress/gzip"
+	b64 "encoding/base64"
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnpacking(t *testing.T) {
+	input := "H4sIAAAAAAAAADWOTQuCQBRF/8ow6wj6ENRdhLXIClJoERKTvsZHOiPzxiLE/96YtTzcy72n4zUQCQnpuwEe8vXxkJ6O8XUfJclqG/EJ1y8FZkgq3RYvYfMy1pJcUGm5NbptXDZSYg2IekRqb5QbbCxqtcHKgiEeXrJvL3qCsgN2HIuxbtFpWFG7sdky8L1ZECwXc9+b/PUGgXPMfnrspxeydQn5A5VkJYjKlkzfWeGWUInhme1QASEx+qpNeZ/1H1PFPn3yAAAA"
+
+	decoded, err := b64.StdEncoding.DecodeString(input)
+	assert.NoError(t, err)
+
+	output, err := unpack(decoded)
+	assert.NoError(t, err)
+
+	expectedOutput := LogEventBatch{
+		MessageType:         "CONTROL_MESSAGE",
+		Owner:               "CloudwatchLogs",
+		LogGroup:            "",
+		LogStream:           "",
+		SubscriptionFilters: []string{},
+		LogEvents: []LogEvent{
+			{
+				ID:        "",
+				Timestamp: 1498519943285,
+				Message:   "CWL CONTROL MESSAGE: Checking health of destination Kinesis stream.",
+			},
+		},
+	}
+	assert.Equal(t, expectedOutput, output)
+}
+
+func pack(input LogEventBatch) (string, error) {
+	src, err := json.Marshal(input)
+	if err != nil {
+		return "", err
+	}
+
+	// Gzip
+	var b bytes.Buffer
+	gz := gzip.NewWriter(&b)
+	if _, err := gz.Write(src); err != nil {
+		return "", err
+	}
+	if err := gz.Flush(); err != nil {
+		panic(err)
+	}
+	if err := gz.Close(); err != nil {
+		return "", err
+	}
+
+	// Base64 Encode
+	return b64.StdEncoding.EncodeToString([]byte(b.String())), nil
+}
+
+func TestFullLoop(t *testing.T) {
+	input := `{
+  "messageType": "DATA_MESSAGE",
+  "owner": "123456789012",
+  "logGroup": "/aws/batch/job",
+  "logStream": "environment--app/11111111-2222-3333-4444-555566667777/88889999-0000-aaa-bbbb-ccccddddeeee",
+  "subscriptionFilters": [
+    "MySubscriptionFilter"
+  ],
+  "logEvents": [
+    {
+      "id": "33418742379011144044923130086453437181614530551221780480",
+      "timestamp": 1498548236012,
+      "message": "some log line"
+    },
+    {
+      "id": "33418742387663833181953011865369295871402094815542181889",
+      "timestamp": 1498548236400,
+      "message": "2017/06/27 07:23:56 Another log line"
+    }
+  ]
+}`
+
+	var leb LogEventBatch
+	err := json.Unmarshal([]byte(input), &leb)
+	assert.NoError(t, err)
+
+	packed, err := pack(leb)
+	assert.NoError(t, err)
+
+	decoded, err := b64.StdEncoding.DecodeString(packed)
+	assert.NoError(t, err)
+
+	output, err := unpack(decoded)
+	assert.NoError(t, err)
+
+	assert.Equal(t, leb, output)
+}
+
+func TestSplit(t *testing.T) {
+	input := LogEventBatch{
+		MessageType:         "DATA_MESSAGE",
+		Owner:               "123456789012",
+		LogGroup:            "/aws/batch/job",
+		LogStream:           "env--app/12345678-1234-1234-1234-555566667777/88889999-0000-aaaa-bbbb-ccccddddeeee",
+		SubscriptionFilters: []string{"MySubscriptionFilter"},
+		LogEvents: []LogEvent{
+			{
+				ID:        "99999992379011144044923130086453437181614530551221780480",
+				Timestamp: 1498519943285,
+				Message:   "some log line",
+			},
+			{
+				ID:        "99999992387663833181953011865369295871402094815542181889",
+				Timestamp: 1498519943285,
+				Message:   "another log line",
+			},
+		},
+	}
+	prodEnv := false
+	lines := Split(input, prodEnv)
+	expected := [][]byte{
+		[]byte("2017-06-26T23:32:23.285001+00:00 aws-batch env--app/arn%3Aaws%3Aecs%3Aus-east-1%3A999988887777%3Atask%2F12345678-1234-1234-1234-555566667777[1]: some log line"),
+		[]byte("2017-06-26T23:32:23.285001+00:00 aws-batch env--app/arn%3Aaws%3Aecs%3Aus-east-1%3A999988887777%3Atask%2F12345678-1234-1234-1234-555566667777[1]: another log line"),
+	}
+	assert.Equal(t, expected, lines)
+}
+
+func TestSplitFiltersByEnv(t *testing.T) {
+	t.Log("If Split is run with prodEnv == true, it should omit logs with env != production")
+	input := LogEventBatch{
+		MessageType: "DATA_MESSAGE",
+		Owner:       "123456789012",
+		LogGroup:    "/aws/batch/job",
+		LogStream:   "env--app/12345678-1234-1234-1234-555566667777/88889999-0000-aaaa-bbbb-ccccddddeeee",
+		// LogStream:           "environment--app",
+		SubscriptionFilters: []string{"MySubscriptionFilter"},
+		LogEvents: []LogEvent{
+			{
+				ID:        "99999992379011144044923130086453437181614530551221780480",
+				Timestamp: 1498519943285,
+				Message:   "some log line",
+			},
+			{
+				ID:        "99999992387663833181953011865369295871402094815542181889",
+				Timestamp: 1498519943285,
+				Message:   "another log line",
+			},
+		},
+	}
+	prodEnv := true
+	lines := Split(input, prodEnv)
+	expected := [][]byte{}
+	assert.Equal(t, expected, lines)
+
+	t.Log("If Split is run with prodEnv == false, it should omit logs with env == production")
+	input = LogEventBatch{
+		MessageType: "DATA_MESSAGE",
+		Owner:       "123456789012",
+		LogGroup:    "/aws/batch/job",
+		LogStream:   "production--app/12345678-1234-1234-1234-555566667777/88889999-0000-aaaa-bbbb-ccccddddeeee",
+		// LogStream:           "environment--app",
+		SubscriptionFilters: []string{"MySubscriptionFilter"},
+		LogEvents: []LogEvent{
+			{
+				ID:        "99999992379011144044923130086453437181614530551221780480",
+				Timestamp: 1498519943285,
+				Message:   "some log line",
+			},
+			{
+				ID:        "99999992387663833181953011865369295871402094815542181889",
+				Timestamp: 1498519943285,
+				Message:   "another log line",
+			},
+		},
+	}
+	prodEnv = false
+	lines = Split(input, prodEnv)
+	expected = [][]byte{}
+	assert.Equal(t, expected, lines)
+}