support AWS SQS as file change notification message queue

weed/replication/sub/notification_kafka.go

@@ -0,0 +1,158 @@
+package sub
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"sync"
+	"time"
+
+	"github.com/Shopify/sarama"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+	"github.com/golang/protobuf/proto"
+)
+
+func init() {
+	NotificationInputs = append(NotificationInputs, &KafkaInput{})
+}
+
+type KafkaInput struct {
+	topic       string
+	consumer    sarama.Consumer
+	messageChan chan *sarama.ConsumerMessage
+}
+
+func (k *KafkaInput) GetName() string {
+	return "kafka"
+}
+
+func (k *KafkaInput) Initialize(configuration util.Configuration) error {
+	glog.V(0).Infof("replication.notification.kafka.hosts: %v\n", configuration.GetStringSlice("hosts"))
+	glog.V(0).Infof("replication.notification.kafka.topic: %v\n", configuration.GetString("topic"))
+	return k.initialize(
+		configuration.GetStringSlice("hosts"),
+		configuration.GetString("topic"),
+		configuration.GetString("offsetFile"),
+		configuration.GetInt("offsetSaveIntervalSeconds"),
+	)
+}
+
+func (k *KafkaInput) initialize(hosts []string, topic string, offsetFile string, offsetSaveIntervalSeconds int) (err error) {
+	config := sarama.NewConfig()
+	config.Consumer.Return.Errors = true
+	k.consumer, err = sarama.NewConsumer(hosts, config)
+	if err != nil {
+		panic(err)
+	} else {
+		glog.V(0).Infof("connected to %v", hosts)
+	}
+
+	k.topic = topic
+	k.messageChan = make(chan *sarama.ConsumerMessage, 1)
+
+	partitions, err := k.consumer.Partitions(topic)
+	if err != nil {
+		panic(err)
+	}
+
+	progress := loadProgress(offsetFile)
+	if progress == nil || progress.Topic != topic {
+		progress = &KafkaProgress{
+			Topic:            topic,
+			PartitionOffsets: make(map[int32]int64),
+		}
+	}
+	progress.lastSaveTime = time.Now()
+	progress.offsetFile = offsetFile
+	progress.offsetSaveIntervalSeconds = offsetSaveIntervalSeconds
+
+	for _, partition := range partitions {
+		offset, found := progress.PartitionOffsets[partition]
+		if !found {
+			offset = sarama.OffsetOldest
+		} else {
+			offset += 1
+		}
+		partitionConsumer, err := k.consumer.ConsumePartition(topic, partition, offset)
+		if err != nil {
+			panic(err)
+		}
+		go func() {
+			for {
+				select {
+				case err := <-partitionConsumer.Errors():
+					fmt.Println(err)
+				case msg := <-partitionConsumer.Messages():
+					k.messageChan <- msg
+					if err := progress.setOffset(msg.Partition, msg.Offset); err != nil {
+						glog.Warningf("set kafka offset: %v", err)
+					}
+				}
+			}
+		}()
+	}
+
+	return nil
+}
+
+func (k *KafkaInput) ReceiveMessage() (key string, message *filer_pb.EventNotification, err error) {
+
+	msg := <-k.messageChan
+
+	key = string(msg.Key)
+	message = &filer_pb.EventNotification{}
+	err = proto.Unmarshal(msg.Value, message)
+
+	return
+}
+
+type KafkaProgress struct {
+	Topic                     string          `json:"topic"`
+	PartitionOffsets          map[int32]int64 `json:"partitionOffsets"`
+	offsetFile                string
+	lastSaveTime              time.Time
+	offsetSaveIntervalSeconds int
+	sync.Mutex
+}
+
+func loadProgress(offsetFile string) *KafkaProgress {
+	progress := &KafkaProgress{}
+	data, err := ioutil.ReadFile(offsetFile)
+	if err != nil {
+		glog.Warningf("failed to read kafka progress file: %s", offsetFile)
+		return nil
+	}
+	err = json.Unmarshal(data, progress)
+	if err != nil {
+		glog.Warningf("failed to read kafka progress message: %s", string(data))
+		return nil
+	}
+	return progress
+}
+
+func (progress *KafkaProgress) saveProgress() error {
+	data, err := json.Marshal(progress)
+	if err != nil {
+		return fmt.Errorf("failed to marshal progress: %v", err)
+	}
+	err = ioutil.WriteFile(progress.offsetFile, data, 0640)
+	if err != nil {
+		return fmt.Errorf("failed to save progress to %s: %v", progress.offsetFile, err)
+	}
+
+	progress.lastSaveTime = time.Now()
+	return nil
+}
+
+func (progress *KafkaProgress) setOffset(parition int32, offset int64) error {
+	progress.Lock()
+	defer progress.Unlock()
+
+	progress.PartitionOffsets[parition] = offset
+	if int(time.Now().Sub(progress.lastSaveTime).Seconds()) > progress.offsetSaveIntervalSeconds {
+		return progress.saveProgress()
+	}
+	return nil
+}