Replace session context with main context

Had to go around this problem using mainContext as sessions get closed quite often when the total topics is huge.
Using context in struct instead of golang suggested approach of passing context around. Since sarama does not support passing context around.

IBM/sarama#1776
golang/go#22602

cmd/redshiftbatcher/main.go

@@ -68,6 +68,7 @@ func run(cmd *cobra.Command, args []string) {
 			groupConfig,
 			redshiftbatcher.NewConsumer(
 				ready,
+				ctx,
 				groupConfig.Kafka,
 				groupConfig.Sarama,
 				groupConfig.LoaderTopicPrefix,

pkg/redshiftbatcher/batch_processor.go

@@ -33,6 +33,9 @@ type batchProcessor struct {
 	// session is required to commit the offsets on succesfull processing
 	session sarama.ConsumerGroupSession
 
+	// mainContext for cancellations
+	mainContext context.Context
+
 	// s3Sink
 	s3sink *s3sink.S3Sink
 
@@ -100,6 +103,7 @@ func newBatchProcessor(
 	topic string,
 	partition int32,
 	session sarama.ConsumerGroupSession,
+	mainContext context.Context,
 	kafkaConfig kafka.KafkaConfig,
 	saramaConfig kafka.SaramaConfig,
 	kafkaLoaderTopicPrefix string,
@@ -146,6 +150,7 @@ func newBatchProcessor(
 		partition:          partition,
 		autoCommit:         saramaConfig.AutoCommit,
 		session:            session,
+		mainContext:        mainContext,
 		s3sink:             sink,
 		s3BucketDir:        viper.GetString("s3sink.bucketDir"),
 		bodyBuf:            bytes.NewBuffer(make([]byte, 0, 4096)),
@@ -179,8 +184,10 @@ func removeEmptyNullValues(value map[string]*string) map[string]*string {
 // TODO: get rid of this https://github.com/herryg91/gobatch/issues/2
 func (b *batchProcessor) ctxCancelled() bool {
 	select {
-	case <-b.session.Context().Done():
-		klog.Infof(
+	case <-b.mainContext.Done():
+		err := b.mainContext.Err()
+		klog.Warningf("Batch processing stopped, mainContext done, ctxErr: %v", err)
+		klog.V(2).Infof(
 			"topic:%s, batchId:%d, lastCommittedOffset:%d: Cancelled.\n",
 			b.topic, b.batchId, b.lastCommittedOffset,
 		)
@@ -393,12 +400,12 @@ func (b *batchProcessor) processMessage(message *serializer.Message, id int) {
 // otherwise return false in case of gracefull shutdown signals being captured,
 // this helps in cleanly shutting down the batch processing.
 func (b *batchProcessor) processBatch(
-	ctx context.Context, datas []interface{}) bool {
+	mainContext context.Context, datas []interface{}) bool {
 
 	b.s3Key = ""
 	for id, data := range datas {
 		select {
-		case <-ctx.Done():
+		case <-mainContext.Done():
 			return false
 		default:
 			b.processMessage(data.(*serializer.Message), id)
@@ -423,7 +430,7 @@ func (b *batchProcessor) process(workerID int, datas []interface{}) {
 		b.topic, b.batchId, len(datas),
 	)
 
-	done := b.processBatch(b.session.Context(), datas)
+	done := b.processBatch(b.mainContext, datas)
 	if !done {
 		b.handleShutdown()
 		return

pkg/redshiftbatcher/consumer.go

@@ -1,14 +1,16 @@
 package redshiftbatcher
 
 import (
+	"context"
 	"github.com/Shopify/sarama"
 	"github.com/practo/klog/v2"
 	"github.com/practo/tipoca-stream/redshiftsink/pkg/kafka"
 )
 
-func NewConsumer(ready chan bool, kafkaConfig kafka.KafkaConfig, saramaConfig kafka.SaramaConfig, loaderPrefix string) consumer {
+func NewConsumer(ready chan bool, mainContext context.Context, kafkaConfig kafka.KafkaConfig, saramaConfig kafka.SaramaConfig, loaderPrefix string) consumer {
 	return consumer{
 		ready:                  ready,
+		mainContext:            mainContext,
 		kafkaConfig:            kafkaConfig,
 		saramaConfig:           saramaConfig,
 		kafkaLoaderTopicPrefix: loaderPrefix,
@@ -23,6 +25,7 @@ func NewConsumer(ready chan bool, kafkaConfig kafka.KafkaConfig, saramaConfig ka
 type consumer struct {
 	// Ready is used to signal the main thread about the readiness
 	ready                  chan bool
+	mainContext            context.Context
 	kafkaConfig            kafka.KafkaConfig
 	saramaConfig           kafka.SaramaConfig
 	kafkaLoaderTopicPrefix string
@@ -60,6 +63,7 @@ func (c consumer) processMessage(
 			message.Topic,
 			message.Partition,
 			session,
+			c.mainContext,
 			c.kafkaConfig,
 			c.saramaConfig,
 			c.kafkaLoaderTopicPrefix,
@@ -69,8 +73,9 @@ func (c consumer) processMessage(
 	c.batcher.processor.session = session
 
 	select {
-	case <-c.batcher.processor.session.Context().Done():
-		klog.Info("Graceful shutdown requested, not inserting in batch")
+	case <-c.mainContext.Done():
+		err := c.mainContext.Err()
+		klog.Warningf("Batch insert stopped, mainContext done, ctxErr: %v", err)
 		return nil
 	default:
 		c.batcher.Insert(message)
@@ -98,7 +103,7 @@ func (c consumer) ConsumeClaim(session sarama.ConsumerGroupSession,
 	// https://github.com/Shopify/sarama/blob/master/consumer_group.go#L27-L29
 	for message := range claim.Messages() {
 		select {
-		case <-session.Context().Done():
+		case <-c.mainContext.Done():
 			klog.Infof(
 				"%s: Gracefully shutdown. Stopped taking new messages.",
 				claim.Topic(),