adjust channel ownership for group

allgroup.go

@@ -33,11 +33,8 @@ type AllGroup struct {
 
 // start is a blocking operation which will loop and attempt to find new
 // shards on a regular cadence.
-func (g *AllGroup) Start(ctx context.Context) chan *kinesis.Shard {
-	var (
-		shardc = make(chan *kinesis.Shard, 1)
-		ticker = time.NewTicker(30 * time.Second)
-	)
+func (g *AllGroup) Start(ctx context.Context, shardc chan *kinesis.Shard) {
+	var ticker = time.NewTicker(30 * time.Second)
 	g.findNewShards(shardc)
 
 	// Note: while ticker is a rather naive approach to this problem,
@@ -49,7 +46,6 @@ func (g *AllGroup) Start(ctx context.Context) chan *kinesis.Shard {
 	// necessarily close at the same time, so we could potentially get a
 	// thundering heard of notifications from the consumer.
 
-	go func() {
 	for {
 		select {
 		case <-ctx.Done():
@@ -59,9 +55,6 @@ func (g *AllGroup) Start(ctx context.Context) chan *kinesis.Shard {
 			g.findNewShards(shardc)
 		}
 	}
-	}()
-
-	return shardc
 }
 
 func (g *AllGroup) GetCheckpoint(streamName, shardID string) (string, error) {
@@ -83,7 +76,7 @@ func (g *AllGroup) findNewShards(shardc chan *kinesis.Shard) {
 
 	shards, err := listShards(g.ksis, g.streamName)
 	if err != nil {
-		g.logger.Log("[GROUP]", err)
+		g.logger.Log("[GROUP] error:", err)
 		return
 	}
 

consumer.go

@@ -88,10 +88,11 @@ func (c *Consumer) Scan(ctx context.Context, fn ScanFunc) error {
 
 	var (
 		errc   = make(chan error, 1)
-		shardc = c.group.Start(ctx)
+		shardc = make(chan *kinesis.Shard, 1)
 	)
 
 	go func() {
+		c.group.Start(ctx, shardc)
 		<-ctx.Done()
 		close(shardc)
 	}()
@@ -130,9 +131,9 @@ func (c *Consumer) ScanShard(ctx context.Context, shardID string, fn ScanFunc) e
 		return fmt.Errorf("get shard iterator error: %v", err)
 	}
 
-	c.logger.Log("[START]\t", shardID, lastSeqNum)
+	c.logger.Log("[CONSUMER] start scan:", shardID, lastSeqNum)
 	defer func() {
-		c.logger.Log("[STOP]\t", shardID)
+		c.logger.Log("[CONSUMER] stop scan:", shardID)
 	}()
 
 	for {
@@ -176,7 +177,7 @@ func (c *Consumer) ScanShard(ctx context.Context, shardID string, fn ScanFunc) e
 			}
 
 			if isShardClosed(resp.NextShardIterator, shardIterator) {
-				c.logger.Log("[CLOSED]\t", shardID)
+				c.logger.Log("[CONSUMER] shard closed:", shardID)
 				return nil
 			}
 

examples/producer/README.md

@@ -8,7 +8,7 @@ Export the required environment vars for connecting to the Kinesis stream:
 
 ```
 export AWS_PROFILE=
-export AWS_REGION_NAME=
+export AWS_REGION=
 ```
 
 ### Running the code

group.go

@@ -8,7 +8,7 @@ import (
 
 // Group interface used to manage which shard to process
 type Group interface {
-	Start(ctx context.Context) chan *kinesis.Shard
+	Start(ctx context.Context, shardc chan *kinesis.Shard)
 	GetCheckpoint(streamName, shardID string) (string, error)
 	SetCheckpoint(streamName, shardID, sequenceNumber string) error
 }