[GitHub] [pulsar] wolfstudy commented on a change in pull request #3854: [issue #3767] support go function for pulsar

[GitBox <gi...@apache.org>]

wolfstudy commented on a change in pull request #3854: [issue #3767] support go function for pulsar
URL: https://github.com/apache/pulsar/pull/3854#discussion_r271557502
 
 

 ##########
 File path: pulsar-function-go/pf/instance.go
 ##########
 @@ -0,0 +1,265 @@
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+//
+
+package pf
+
+import (
+	"context"
+	"math"
+	"time"
+
+	"github.com/apache/pulsar/pulsar-client-go/pulsar"
+	"github.com/apache/pulsar/pulsar-function-go/log"
+	"github.com/apache/pulsar/pulsar-function-go/pb"
+)
+
+type GoInstance struct {
+	function  Function
+	context   *FunctionContext
+	producer  pulsar.Producer
+	consumers map[string]pulsar.Consumer
+	client    pulsar.Client
+}
+
+// NewGoInstance init GoInstance and init function context
+func NewGoInstance() *GoInstance {
+	goInstance := &GoInstance{
+		context:   NewFuncContext(),
+		consumers: make(map[string]pulsar.Consumer),
+	}
+	return goInstance
+}
+
+func (gi *GoInstance) StartFunction(function Function) {
+	gi.function = function
+	err := gi.setupClient()
+	if err != nil {
+		panic("setup client failed, please check.")
+	}
+	err = gi.setupProducer()
+	if err != nil {
+		panic("setup producer failed, please check.")
+	}
+	channel, err := gi.setupConsumer()
+	if err != nil {
+		panic("setup consumer failed, please check.")
+	}
+
+CLOSE:
+	for {
+		select {
+		case cm := <-channel:
+			msgInput := cm.Message
+			atMostOnce := gi.context.InstanceConf.FuncDetails.ProcessingGuarantees == pb.ProcessingGuarantees_ATMOST_ONCE
+			autoAck := gi.context.InstanceConf.FuncDetails.AutoAck
+			if autoAck && atMostOnce {
+				gi.ackInputMessage(msgInput)
+			}
+			output, err := gi.handlerMsg(msgInput)
+			if err != nil {
+				log.Errorf("handler message error:%v", err)
+				gi.nackInputMessage(msgInput)
+			} else {
+				gi.processResult(msgInput, output)
+			}
+
+		case <-time.After(getIdleTimeout(time.Millisecond * gi.context.InstanceConf.KillAfterIdleMs)):
+			close(channel)
+			break CLOSE
+		}
+	}
+
+	gi.close()
+}
+
+func (gi *GoInstance) setupClient() error {
+	client, err := pulsar.NewClient(pulsar.ClientOptions{
+		URL: gi.context.InstanceConf.PulsarServiceURL,
+	})
+	if err != nil {
+		log.Errorf("create client error:%v", err)
+		return err
+	}
+	gi.client = client
+	return nil
+}
+
+func (gi *GoInstance) setupProducer() (err error) {
+	if gi.context.InstanceConf.FuncDetails.Sink.Topic != "" && len(gi.context.InstanceConf.FuncDetails.Sink.Topic) > 0 {
+		log.Debugf("Setting up producer for topic %s", gi.context.InstanceConf.FuncDetails.Sink.Topic)
+		properties := getProperties(getDefaultSubscriptionName(
+			gi.context.InstanceConf.FuncDetails.Tenant,
+			gi.context.InstanceConf.FuncDetails.Namespace,
+			gi.context.InstanceConf.FuncDetails.Name), gi.context.InstanceConf.InstanceID)
+		gi.producer, err = gi.client.CreateProducer(pulsar.ProducerOptions{
+			Topic:                   gi.context.InstanceConf.FuncDetails.Sink.Topic,
+			Properties:              properties,
+			CompressionType:         pulsar.LZ4,
+			BlockIfQueueFull:        true,
+			Batching:                true,
+			BatchingMaxPublishDelay: time.Millisecond * 10,
+			// set send timeout to be infinity to prevent potential deadlock with consumer
+			// that might happen when consumer is blocked due to unacked messages
+			SendTimeout: 0,
+		})
+		if err != nil {
+			log.Errorf("create producer error:%s", err.Error())
+			return err
+		}
+	}
+	return nil
+}
+
+func (gi *GoInstance) setupConsumer() (chan pulsar.ConsumerMessage, error) {
+	subscriptionType := pulsar.Shared
+	if int32(gi.context.InstanceConf.FuncDetails.Source.SubscriptionType) == pb.SubscriptionType_value["FAILOVER"] {
+		subscriptionType = pulsar.Failover
+	}
+
+	funcDetails := gi.context.InstanceConf.FuncDetails
+	subscriptionName := funcDetails.Tenant + "/" + funcDetails.Namespace + "/" + funcDetails.Name
+
+	properties := getProperties(getDefaultSubscriptionName(
+		funcDetails.Tenant,
+		funcDetails.Namespace,
+		funcDetails.Name), gi.context.InstanceConf.InstanceID)
+
+	channel := make(chan pulsar.ConsumerMessage)
+
+	var (
+		consumer pulsar.Consumer
+		err      error
+	)
+
+	for topic, consumerConf := range funcDetails.Source.InputSpecs {
+		log.Debugf("Setting up consumer for topic: %s with subscription name: %s", topic, subscriptionName)
+		if consumerConf.ReceiverQueueSize != nil {
+			if consumerConf.IsRegexPattern {
+				consumer, err = gi.client.Subscribe(pulsar.ConsumerOptions{
+					TopicsPattern:     topic,
+					ReceiverQueueSize: int(consumerConf.ReceiverQueueSize.Value),
+					SubscriptionName:  subscriptionName,
+					Properties:        properties,
+					Type:              subscriptionType,
+					MessageChannel:    channel,
+				})
+			} else {
+				consumer, err = gi.client.Subscribe(pulsar.ConsumerOptions{
+					Topic:             topic,
+					SubscriptionName:  subscriptionName,
+					Properties:        properties,
+					Type:              subscriptionType,
+					ReceiverQueueSize: int(consumerConf.ReceiverQueueSize.Value),
+					MessageChannel:    channel,
+				})
+			}
+		} else {
+			if consumerConf.IsRegexPattern {
+				consumer, err = gi.client.Subscribe(pulsar.ConsumerOptions{
+					TopicsPattern:    topic,
+					SubscriptionName: subscriptionName,
+					Properties:       properties,
+					Type:             subscriptionType,
+					MessageChannel:   channel,
+				})
+			} else {
+				consumer, err = gi.client.Subscribe(pulsar.ConsumerOptions{
+					Topic:            topic,
+					SubscriptionName: subscriptionName,
+					Properties:       properties,
+					Type:             subscriptionType,
+					MessageChannel:   channel,
+				})
+
+			}
+		}
+
+		if err != nil {
+			log.Errorf("create consumer error:%s", err.Error())
+			return nil, err
+		}
+		gi.consumers[topic] = consumer
+		gi.context.InputTopics = append(gi.context.InputTopics, topic)
+	}
+	return channel, nil
+}
+
+func (gi *GoInstance) handlerMsg(input pulsar.Message) (output []byte, err error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	ctx = NewContext(ctx, gi.context)
+	msgInput := input.Payload()
+	return gi.function.Process(ctx, msgInput)
+}
+
+func (gi *GoInstance) processResult(msgInput pulsar.Message, output []byte) {
+	atMostOnce := gi.context.InstanceConf.FuncDetails.ProcessingGuarantees == pb.ProcessingGuarantees_ATMOST_ONCE
+	autoAck := gi.context.InstanceConf.FuncDetails.AutoAck
+
+	if output != nil && gi.context.InstanceConf.FuncDetails.Sink.Topic != "" {
+		asyncMsg := pulsar.ProducerMessage{
+			Payload: output,
+		}
+		// Attempt to send the message asynchronously and handle the response
+		gi.producer.SendAsync(context.Background(), asyncMsg, func(message pulsar.ProducerMessage, e error) {
+			if e != nil {
+				log.Fatal(e)
+				gi.nackInputMessage(msgInput)
+			} else if !atMostOnce && autoAck {
+				gi.ackInputMessage(msgInput)
+			}
+		})
+	} else {
+		if autoAck {
+			gi.ackInputMessage(msgInput)
+		}
+	}
+}
+
+// ackInputMessage doesn't produce any result or the user doesn't want the result.
+func (gi *GoInstance) ackInputMessage(inputMessage pulsar.Message) {
+	gi.consumers[inputMessage.Topic()].Ack(inputMessage)
+}
+
+func (gi *GoInstance) nackInputMessage(inputMessage pulsar.Message) {
 
 Review comment:
   Because in the current version of pulsar-client-go, we do not support this operation. This feature will be implemented in the next pull request.

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