merlimat commented on a change in pull request #86: Simplify and refactor parts of the single topic consumer. URL: https://github.com/apache/pulsar-client-go/pull/86#discussion_r344845948
########## File path: pulsar/consumer_impl.go ########## @@ -0,0 +1,257 @@ +// 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 pulsar + +import ( + "context" + "errors" + "fmt" + "sync" + + log "github.com/sirupsen/logrus" + + "github.com/apache/pulsar-client-go/pkg/pb" + "github.com/apache/pulsar-client-go/pulsar/internal" +) + +var ErrConsumerClosed = errors.New("consumer closed") + +type consumer struct { + topic string + + options ConsumerOptions + + consumers []*partitionConsumer + + // channel used to deliver message to clients + messageCh chan ConsumerMessage + + closeCh chan struct{} + errorCh chan error + + log *log.Entry +} + +func newConsumer(client *client, options ConsumerOptions) (Consumer, error) { + if options.Topic == "" && options.Topics == nil && options.TopicsPattern == "" { + return nil, newError(TopicNotFound, "topic is required") + } + + if options.SubscriptionName == "" { + return nil, newError(SubscriptionNotFound, "subscription name is required for consumer") + } + + if options.ReceiverQueueSize == 0 { + options.ReceiverQueueSize = 1000 + } + + // did the user pass in a message channel? + messageCh := options.MessageChannel + if options.MessageChannel == nil { + messageCh = make(chan ConsumerMessage, 10) + } + + // single topic consumer + if options.Topic != "" || len(options.Topics) == 1 { + topic := options.Topic + if topic == "" { + topic = options.Topics[0] + } + + if _, err := internal.ParseTopicName(topic); err != nil { + return nil, err + } + + return topicSubscribe(client, options, topic, messageCh) + } + + return nil, newError(ResultInvalidTopicName, "topic name is required for consumer") +} + +func topicSubscribe(client *client, options ConsumerOptions, topic string, + messageCh chan ConsumerMessage) (Consumer, error) { + consumer := &consumer{ + topic: topic, + messageCh: messageCh, + errorCh: make(chan error), + log: log.WithField("topic", topic), + } + + partitions, err := client.TopicPartitions(topic) + if err != nil { + return nil, err + } + + numPartitions := len(partitions) + consumer.consumers = make([]*partitionConsumer, numPartitions) + + type ConsumerError struct { + err error + partition int + consumer *partitionConsumer + } + + receiverQueueSize := options.ReceiverQueueSize + var wg sync.WaitGroup + ch := make(chan ConsumerError, numPartitions) + for partitionIdx, partitionTopic := range partitions { + wg.Add(1) + go func(idx int, pt string) { + defer wg.Done() + opts := &partitionConsumerOpts{ + topic: pt, + subscription: options.SubscriptionName, + subscriptionType: options.Type, + subscriptionInitPos: options.SubscriptionInitPos, + partitionIdx: idx, + receiverQueueSize: receiverQueueSize, + } + cons, err := newPartitionConsumer(consumer, client, opts, messageCh) + ch <- ConsumerError{ + err: err, + partition: idx, + consumer: cons, + } + }(partitionIdx, partitionTopic) + } + + go func() { + wg.Wait() + close(ch) + }() + + for ce := range ch { + if ce.err != nil { + err = ce.err + } else { + consumer.consumers[ce.partition] = ce.consumer + } + } + + if err != nil { + // Since there were some failures, cleanup all the partitions that succeeded in creating the consumer + for _, c := range consumer.consumers { + if c != nil { + _ = c.Close() + } + } + return nil, err + } + + return consumer, nil +} + +func (c *consumer) Topic() string { + return c.topic +} + +func (c *consumer) Subscription() string { + return c.options.SubscriptionName +} + +func (c *consumer) Unsubscribe() error { + var errMsg string + for _, consumer := range c.consumers { + if err := consumer.Unsubscribe(); err != nil { + errMsg += fmt.Sprintf("topic %s, subscription %s: %s", c.Topic(), c.Subscription(), err) + } + } + if errMsg != "" { + return fmt.Errorf(errMsg) + } + return nil +} + +func (c *consumer) Receive(ctx context.Context) (message Message, err error) { + //fmt.Println("recv chan", c.messageCh) Review comment: Remove commented line (or convert into log.debug) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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