bd42663013
As we move towards consumer groups we'll need to support the current "consume all shards" strategy, and setup the codebase for the anticipated "consume balanced shards."
135 lines
3 KiB
Go
135 lines
3 KiB
Go
package main
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import (
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"context"
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"expvar"
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"flag"
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"fmt"
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"log"
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"net"
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"net/http"
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"os"
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"os/signal"
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alog "github.com/apex/log"
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"github.com/apex/log/handlers/text"
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"github.com/aws/aws-sdk-go/aws"
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"github.com/aws/aws-sdk-go/aws/awserr"
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"github.com/aws/aws-sdk-go/aws/session"
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"github.com/aws/aws-sdk-go/service/dynamodb"
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"github.com/aws/aws-sdk-go/service/kinesis"
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consumer "github.com/harlow/kinesis-consumer"
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storage "github.com/harlow/kinesis-consumer/checkpoint/ddb"
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)
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// kick off a server for exposing scan metrics
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func init() {
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sock, err := net.Listen("tcp", "localhost:8080")
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if err != nil {
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log.Printf("net listen error: %v", err)
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}
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go func() {
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fmt.Println("Metrics available at http://localhost:8080/debug/vars")
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http.Serve(sock, nil)
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}()
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}
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// A myLogger provides a minimalistic logger satisfying the Logger interface.
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type myLogger struct {
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logger alog.Logger
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}
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// Log logs the parameters to the stdlib logger. See log.Println.
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func (l *myLogger) Log(args ...interface{}) {
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l.logger.Infof("producer: %v", args...)
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}
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func main() {
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// Wrap myLogger around apex logger
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log := &myLogger{
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logger: alog.Logger{
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Handler: text.New(os.Stdout),
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Level: alog.DebugLevel,
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},
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}
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var (
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app = flag.String("app", "", "Consumer app name")
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stream = flag.String("stream", "", "Stream name")
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table = flag.String("table", "", "Checkpoint table name")
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)
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flag.Parse()
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sess, err := session.NewSession(aws.NewConfig())
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if err != nil {
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log.Log("new session error: %v", err)
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}
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// New Kinesis and DynamoDB clients (if you need custom config)
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myKsis := kinesis.New(sess)
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myDdbClient := dynamodb.New(sess)
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// ddb persitance
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ddb, err := storage.New(*app, *table, storage.WithDynamoClient(myDdbClient), storage.WithRetryer(&MyRetryer{}))
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if err != nil {
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log.Log("checkpoint error: %v", err)
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}
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// expvar counter
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var counter = expvar.NewMap("counters")
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// consumer
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c, err := consumer.New(
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*stream,
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consumer.WithStorage(ddb),
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consumer.WithLogger(log),
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consumer.WithCounter(counter),
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consumer.WithClient(myKsis),
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)
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if err != nil {
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log.Log("consumer error: %v", err)
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}
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// use cancel func to signal shutdown
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ctx, cancel := context.WithCancel(context.Background())
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// trap SIGINT, wait to trigger shutdown
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signals := make(chan os.Signal, 1)
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signal.Notify(signals, os.Interrupt)
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go func() {
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<-signals
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cancel()
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}()
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// scan stream
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err = c.Scan(ctx, func(r *consumer.Record) error {
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fmt.Println(string(r.Data))
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return nil // continue scanning
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})
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if err != nil {
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log.Log("scan error: %v", err)
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}
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if err := ddb.Shutdown(); err != nil {
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log.Log("storage shutdown error: %v", err)
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}
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}
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// MyRetryer used for storage
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type MyRetryer struct {
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storage.Retryer
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}
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// ShouldRetry implements custom logic for when errors should retry
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func (r *MyRetryer) ShouldRetry(err error) bool {
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if awsErr, ok := err.(awserr.Error); ok {
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switch awsErr.Code() {
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case dynamodb.ErrCodeProvisionedThroughputExceededException, dynamodb.ErrCodeLimitExceededException:
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return true
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default:
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return false
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}
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}
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return false
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}
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