Elia Battiston | 4750d3c | 2022-07-14 13:24:56 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2022-present Open Networking Foundation |
| 3 | |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package clients |
| 18 | |
| 19 | import ( |
| 20 | "context" |
| 21 | "fmt" |
| 22 | "time" |
| 23 | |
| 24 | "github.com/Shopify/sarama" |
| 25 | "github.com/golang/protobuf/proto" |
| 26 | "github.com/opencord/voltha-lib-go/v7/pkg/log" |
| 27 | "github.com/opencord/voltha-protos/v5/go/voltha" |
| 28 | ) |
| 29 | |
| 30 | const ( |
| 31 | volthaEventsTopic = "voltha.events" |
| 32 | kafkaBackoffInterval = time.Second * 10 |
| 33 | ) |
| 34 | |
| 35 | //Used to listen for events coming from VOLTHA |
| 36 | type KafkaConsumer struct { |
| 37 | address string |
| 38 | config *sarama.Config |
| 39 | client sarama.Client |
| 40 | consumer sarama.Consumer |
| 41 | partitionConsumer sarama.PartitionConsumer |
| 42 | highwater int64 |
| 43 | } |
| 44 | |
| 45 | //Creates a sarama client with the specified address |
| 46 | func NewKafkaConsumer(clusterAddress string) *KafkaConsumer { |
| 47 | c := KafkaConsumer{address: clusterAddress} |
| 48 | c.config = sarama.NewConfig() |
| 49 | c.config.ClientID = "bbf-adapter-consumer" |
| 50 | c.config.Consumer.Return.Errors = true |
| 51 | c.config.Consumer.Offsets.Initial = sarama.OffsetNewest |
| 52 | c.config.Version = sarama.V1_0_0_0 |
| 53 | |
| 54 | return &c |
| 55 | } |
| 56 | |
| 57 | //Starts consuming new messages on the voltha events topic, executing the provided callback on each event |
| 58 | func (c *KafkaConsumer) Start(ctx context.Context, eventCallback func(context.Context, *voltha.Event)) error { |
| 59 | var err error |
| 60 | |
| 61 | for { |
| 62 | if c.client, err = sarama.NewClient([]string{c.address}, c.config); err == nil { |
| 63 | logger.Debug(ctx, "kafka-client-created") |
| 64 | break |
| 65 | } else { |
| 66 | logger.Warnw(ctx, "kafka-not-reachable", log.Fields{ |
| 67 | "err": err, |
| 68 | }) |
| 69 | } |
| 70 | |
| 71 | //Wait a bit before trying again |
| 72 | select { |
| 73 | case <-ctx.Done(): |
| 74 | return fmt.Errorf("kafka-client-creation-stopped-due-to-context-done") |
| 75 | case <-time.After(kafkaBackoffInterval): |
| 76 | continue |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | c.consumer, err = sarama.NewConsumerFromClient(c.client) |
| 81 | if err != nil { |
| 82 | return err |
| 83 | } |
| 84 | |
| 85 | partitions, _ := c.consumer.Partitions(volthaEventsTopic) |
| 86 | |
| 87 | // TODO: Add support for multiple partitions |
| 88 | if len(partitions) > 1 { |
| 89 | logger.Warnw(ctx, "only-listening-one-partition", log.Fields{ |
| 90 | "topic": volthaEventsTopic, |
| 91 | "partitionsNum": len(partitions), |
| 92 | }) |
| 93 | } |
| 94 | |
| 95 | hw, err := c.client.GetOffset(volthaEventsTopic, partitions[0], sarama.OffsetNewest) |
| 96 | if err != nil { |
| 97 | return fmt.Errorf("cannot-get-highwater: %v", err) |
| 98 | } |
| 99 | c.highwater = hw |
| 100 | |
| 101 | c.partitionConsumer, err = c.consumer.ConsumePartition(volthaEventsTopic, partitions[0], sarama.OffsetOldest) |
| 102 | if nil != err { |
| 103 | return fmt.Errorf("Error in consume(): Topic %v Partitions: %v", volthaEventsTopic, partitions) |
| 104 | } |
| 105 | |
| 106 | //Start consuming the event topic in a goroutine |
| 107 | logger.Debugw(ctx, "start-consuming-kafka-topic", log.Fields{"topic": volthaEventsTopic}) |
| 108 | go func(topic string, pConsumer sarama.PartitionConsumer) { |
| 109 | for { |
| 110 | select { |
| 111 | case <-ctx.Done(): |
| 112 | logger.Info(ctx, "stopped-listening-for-events-due-to-context-done") |
| 113 | return |
| 114 | case err := <-pConsumer.Errors(): |
| 115 | logger.Errorw(ctx, "kafka-consumer-error", log.Fields{ |
| 116 | "err": err.Error(), |
| 117 | "topic": err.Topic, |
| 118 | "partition": err.Partition, |
| 119 | }) |
| 120 | case msg := <-pConsumer.Messages(): |
| 121 | if msg.Offset <= c.highwater { |
| 122 | continue |
| 123 | } |
| 124 | |
| 125 | //Unmarshal the content of the message to a voltha Event protobuf message |
| 126 | event := &voltha.Event{} |
| 127 | if err := proto.Unmarshal(msg.Value, event); err != nil { |
| 128 | logger.Errorw(ctx, "error-unmarshalling-kafka-event", log.Fields{"err": err}) |
| 129 | continue |
| 130 | } |
| 131 | |
| 132 | eventCallback(ctx, event) |
| 133 | } |
| 134 | } |
| 135 | }(volthaEventsTopic, c.partitionConsumer) |
| 136 | |
| 137 | return nil |
| 138 | } |
| 139 | |
| 140 | //Closes the sarama client and all consumers |
| 141 | func (c *KafkaConsumer) Stop() error { |
| 142 | if err := c.partitionConsumer.Close(); err != nil { |
| 143 | return err |
| 144 | } |
| 145 | |
| 146 | if err := c.consumer.Close(); err != nil { |
| 147 | return err |
| 148 | } |
| 149 | |
| 150 | if err := c.client.Close(); err != nil { |
| 151 | return err |
| 152 | } |
| 153 | |
| 154 | return nil |
| 155 | } |