add shardID to scan func

consumer.go

@@ -30,8 +30,8 @@ func New(streamName string, opts ...Option) (*Consumer, error) {
 	c := &Consumer{
 		streamName:               streamName,
 		initialShardIteratorType: kinesis.ShardIteratorTypeLatest,
-		store:                    &noopStore{},
-		counter:                  &noopCounter{},
+		store:   &noopStore{},
+		counter: &noopCounter{},
 		logger: &noopLogger{
 			logger: log.New(ioutil.Discard, "", log.LstdFlags),
 		},
@@ -73,10 +73,10 @@ type Consumer struct {
 
 // ScanFunc is the type of the function called for each message read
 // from the stream. The record argument contains the original record
-// returned from the AWS Kinesis library.
+// returned from the AWS Kinesis library and the shardID.
 // If an error is returned, scanning stops. The sole exception is when the
 // function returns the special value ErrSkipCheckpoint.
-type ScanFunc func(*Record) error
+type ScanFunc func(*Record, string) error
 
 // ErrSkipCheckpoint is used as a return value from ScanFunc to indicate that
 // the current checkpoint should be skipped skipped. It is not returned
@@ -180,7 +180,7 @@ func (c *Consumer) ScanShard(ctx context.Context, shardID string, fn ScanFunc) e
 				case <-ctx.Done():
 					return nil
 				default:
-					err := fn(r)
+					err := fn(r, shardID)
 					if err != nil && err != ErrSkipCheckpoint {
 						return err
 					}