kinesis-consumer/pipeline.go
Harlow Ward 8e8ee5af73 Use golint to update Golang styles
* Update comments and return statements
* Adjust usage of Kinesis library (upgraded local source)
2014-12-10 15:38:19 -08:00

90 lines
2.3 KiB
Go

package connector
import (
"fmt"
"time"
"github.com/sendgridlabs/go-kinesis"
)
// Pipeline is used as a record processor to configure a pipline.
//
// The user should implement this such that each method returns a configured implementation of each
// interface. It has a data type (Model) as Records come in as a byte[] and are transformed to a Model.
// Then they are buffered in Model form and when the buffer is full, Models's are passed to the emitter.
type Pipeline struct {
Buffer Buffer
Checkpoint Checkpoint
Emitter Emitter
Filter Filter
StreamName string
Transformer Transformer
}
// ProcessShard kicks off the process of a Kinesis Shard.
// It is a long running process that will continue to read from the shard.
func (p Pipeline) ProcessShard(ksis *kinesis.Kinesis, shardID string) {
args := kinesis.NewArgs()
args.Add("ShardId", shardID)
args.Add("StreamName", p.StreamName)
if p.Checkpoint.CheckpointExists(shardID) {
args.Add("ShardIteratorType", "AFTER_SEQUENCE_NUMBER")
args.Add("StartingSequenceNumber", p.Checkpoint.SequenceNumber())
} else {
args.Add("ShardIteratorType", "TRIM_HORIZON")
}
shardInfo, err := ksis.GetShardIterator(args)
if err != nil {
fmt.Printf("Error fetching shard itterator: %v", err)
return
}
shardIterator := shardInfo.ShardIterator
for {
args = kinesis.NewArgs()
args.Add("ShardIterator", shardIterator)
recordSet, err := ksis.GetRecords(args)
if err != nil {
fmt.Printf("GetRecords ERROR: %v\n", err)
time.Sleep(10 * time.Second)
continue
}
if len(recordSet.Records) > 0 {
for _, v := range recordSet.Records {
data := v.GetData()
if err != nil {
fmt.Printf("GetData ERROR: %v\n", err)
continue
}
r := p.Transformer.ToRecord(data)
if p.Filter.KeepRecord(r) {
p.Buffer.ProcessRecord(r, v.SequenceNumber)
}
}
} else if recordSet.NextShardIterator == "" || shardIterator == recordSet.NextShardIterator || err != nil {
fmt.Printf("NextShardIterator ERROR: %v\n", err)
break
} else {
fmt.Printf("Sleeping: %v\n", shardID)
time.Sleep(10 * time.Second)
}
if p.Buffer.ShouldFlush() {
fmt.Printf("Emitting to Shard: %v\n", shardID)
p.Emitter.Emit(p.Buffer, p.Transformer)
p.Checkpoint.SetCheckpoint(shardID, p.Buffer.LastSequenceNumber())
p.Buffer.Flush()
}
shardIterator = recordSet.NextShardIterator
}
}