Use stdlib logging, default to discard

README.md

@@ -24,9 +24,6 @@ import(
 )
 
 func main() {
-	log.SetHandler(text.New(os.Stderr))
-	log.SetLevel(log.DebugLevel)
-
 	var (
 		app    = flag.String("app", "", "App name")
 		stream = flag.String("stream", "", "Stream name")
@@ -59,7 +56,7 @@ func main() {
 }
 ```
 
-### Checkpoint
+## Checkpoint
 
 To record the progress of the consumer in the stream we use a checkpoint to store the last sequence number the consumer has read from a particular shard. 
 
@@ -71,7 +68,7 @@ The uniq identifier for a consumer is `[appName, streamName, shardID]`
 
 There are currently two storage types for checkpoints:
 
-### Redis
+### Redis Checkpoint
 
 The Redis checkpoint requries App Name, and Stream Name:
 
@@ -85,7 +82,7 @@ if err != nil {
 }
 ```
 
-### DynamoDB
+### DynamoDB Checkpoint
 
 The DynamoDB checkpoint requires Table Name, App Name, and Stream Name:
 
@@ -103,7 +100,7 @@ To leverage the DDB checkpoint we'll also need to create a table:
 
 <img width="659" alt="screen shot 2017-11-20 at 9 16 14 am" src="https://user-images.githubusercontent.com/739782/33033316-db85f848-cdd8-11e7-941a-0a87d8ace479.png">
 
-### Options
+## Options
 
 The consumer allows the following optional overrides:
 
@@ -122,32 +119,22 @@ c, err := consumer.New(
 )
 ```
 
-### Logging
+## Logging
 
-[Apex Log](https://medium.com/@tjholowaychuk/apex-log-e8d9627f4a9a#.5x1uo1767) is used for logging Info. Override the logs format with other [Log Handlers](https://github.com/apex/log/tree/master/_examples). For example using the "json" log handler:
+The package defaults to `ioutil.Discard` so swallow all logs. This can be customized with the preferred logging strategy:
 
 ```go
-import(
-  "github.com/apex/log"
-  "github.com/apex/log/handlers/json"
-)
-
 func main() {
 	// ...
 
-  log.SetHandler(json.New(os.Stderr))
-  log.SetLevel(log.DebugLevel)
+	// logger
+	logger := log.New(os.Stdout, "consumer-example: ", log.LstdFlags)
+
+	// consumer
+	c, err := consumer.New(checkpoint, appName, streamName, consumer.WithLogger(logger))
 }
 ```
 
-Which will producde the following logs:
-
-```
-  INFO[0000] processing                app=test shard=shardId-000000000000 stream=test
-  INFO[0008] checkpoint                app=test shard=shardId-000000000000 stream=test
-  INFO[0012] checkpoint                app=test shard=shardId-000000000000 stream=test
-```
-
 ## Contributing
 
 Please see [CONTRIBUTING.md] for more information. Thank you, [contributors]!

consumer.go

@@ -3,9 +3,10 @@ package consumer
 import (
 	"context"
 	"fmt"
+	"io/ioutil"
+	"log"
 	"sync"
 
-	"github.com/apex/log"
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/kinesis"
@@ -26,7 +27,7 @@ func WithCheckpoint(checkpoint checkpoint.Checkpoint) Option {
 }
 
 // WithLogger overrides the default logger
-func WithLogger(logger log.Interface) Option {
+func WithLogger(logger *log.Logger) Option {
 	return func(c *Consumer) error {
 		c.logger = logger
 		return nil
@@ -63,11 +64,7 @@ func New(checkpoint checkpoint.Checkpoint, app, stream string, opts ...Option) (
 
 	// provide default logger
 	if c.logger == nil {
-		c.logger = log.Log.WithFields(log.Fields{
-			"package": "kinesis-consumer",
-			"app": app,
-			"stream":  stream,
-		})
+		c.logger = log.New(ioutil.Discard, "kinesis-consumer: ", log.LstdFlags)
 	}
 
 	// provide a default kinesis client
@@ -83,7 +80,7 @@ type Consumer struct {
 	appName    string
 	streamName string
 	client     *kinesis.Kinesis
-	logger     log.Interface
+	logger     *log.Logger
 	checkpoint checkpoint.Checkpoint
 }
 
@@ -123,21 +120,19 @@ func (c *Consumer) Scan(ctx context.Context, fn func(*kinesis.Record) bool) erro
 // for each record and checkpoints after each page is processed.
 // Note: returning `false` from the callback func will end the scan.
 func (c *Consumer) ScanShard(ctx context.Context, shardID string, fn func(*kinesis.Record) bool) {
-	var logger = c.logger.WithFields(log.Fields{"shard": shardID})
-
 	lastSeqNum, err := c.checkpoint.Get(shardID)
 	if err != nil {
-		logger.WithError(err).Error("get checkpoint")
+		c.logger.Printf("get checkpoint error: %v", err)
 		return
 	}
 
 	shardIterator, err := c.getShardIterator(shardID, lastSeqNum)
 	if err != nil {
-		logger.WithError(err).Error("getShardIterator")
+		c.logger.Printf("get shard iterator error: %v", err)
 		return
 	}
 
-	logger.Info("scanning shard")
+	c.logger.Println("scanning", shardID)
 
 loop:
 	for {
@@ -154,7 +149,7 @@ loop:
 			if err != nil {
 				shardIterator, err = c.getShardIterator(shardID, lastSeqNum)
 				if err != nil {
-					logger.WithError(err).Error("getShardIterator")
+					c.logger.Printf("get shard iterator error: %v", err)
 					break loop
 				}
 				continue
@@ -173,16 +168,16 @@ loop:
 					}
 				}
 
-				logger.WithField("count", len(resp.Records)).Info("checkpoint")
+				c.logger.Println("checkpointing", shardID, len(resp.Records))
 				if err := c.checkpoint.Set(shardID, lastSeqNum); err != nil {
-					c.logger.WithError(err).Error("set checkpoint error")
+					c.logger.Printf("set checkpoint error: %v", err)
 				}
 			}
 
 			if resp.NextShardIterator == nil || shardIterator == resp.NextShardIterator {
 				shardIterator, err = c.getShardIterator(shardID, lastSeqNum)
 				if err != nil {
-					logger.WithError(err).Error("getShardIterator")
+					c.logger.Printf("get shard iterator error: %v", err)
 					break loop
 				}
 			} else {
@@ -195,8 +190,9 @@ loop:
 		return
 	}
 
+	c.logger.Println("checkpointing", shardID)
 	if err := c.checkpoint.Set(shardID, lastSeqNum); err != nil {
-		c.logger.WithError(err).Error("set checkpoint error")
+		c.logger.Printf("set checkpoint error: %v", err)
 	}
 }
 
@@ -215,7 +211,6 @@ func (c *Consumer) getShardIterator(shardID, lastSeqNum string) (*string, error)
 
 	resp, err := c.client.GetShardIterator(params)
 	if err != nil {
-		c.logger.WithError(err).Error("GetShardIterator")
 		return nil, err
 	}
 

examples/consumer/main.go

@@ -4,32 +4,31 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"log"
 	"os"
 
-	"github.com/apex/log"
-	"github.com/apex/log/handlers/text"
 	consumer "github.com/harlow/kinesis-consumer"
 	checkpoint "github.com/harlow/kinesis-consumer/checkpoint/redis"
 )
 
 func main() {
-	log.SetHandler(text.New(os.Stderr))
-	log.SetLevel(log.DebugLevel)
-
 	var (
 		app    = flag.String("app", "", "App name")
 		stream = flag.String("stream", "", "Stream name")
 	)
 	flag.Parse()
 
-	// new checkpoint
+	// logger
+	logger := log.New(os.Stdout, "consumer-example: ", log.LstdFlags)
+
+	// checkpoint
 	ck, err := checkpoint.New(*app, *stream)
 	if err != nil {
 		log.Fatalf("checkpoint error: %v", err)
 	}
 
-	// new consumer
-	c, err := consumer.New(ck, *app, *stream)
+	// consumer
+	c, err := consumer.New(ck, *app, *stream, consumer.WithLogger(logger))
 	if err != nil {
 		log.Fatalf("consumer error: %v", err)
 	}