package kafka_consumer import ( "fmt" "log" "strings" "sync" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/plugins/inputs" "github.com/influxdata/telegraf/plugins/parsers" "github.com/Shopify/sarama" "github.com/wvanbergen/kafka/consumergroup" ) type Kafka struct { ConsumerGroup string Topics []string MaxMessageLen int ZookeeperPeers []string ZookeeperChroot string Consumer *consumergroup.ConsumerGroup // Legacy metric buffer support MetricBuffer int // TODO remove PointBuffer, legacy support PointBuffer int Offset string parser parsers.Parser sync.Mutex // channel for all incoming kafka messages in <-chan *sarama.ConsumerMessage // channel for all kafka consumer errors errs <-chan error done chan struct{} // keep the accumulator internally: acc telegraf.Accumulator // doNotCommitMsgs tells the parser not to call CommitUpTo on the consumer // this is mostly for test purposes, but there may be a use-case for it later. doNotCommitMsgs bool } var sampleConfig = ` ## topic(s) to consume topics = ["telegraf"] ## an array of Zookeeper connection strings zookeeper_peers = ["localhost:2181"] ## Zookeeper Chroot zookeeper_chroot = "" ## the name of the consumer group consumer_group = "telegraf_metrics_consumers" ## Offset (must be either "oldest" or "newest") offset = "oldest" ## Data format to consume. ## Each data format has its own unique set of configuration options, read ## more about them here: ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md data_format = "influx" ## Maximum length of a message to consume, in bytes (default 0/unlimited); ## larger messages are dropped max_message_len = 65536 ` func (k *Kafka) SampleConfig() string { return sampleConfig } func (k *Kafka) Description() string { return "Read metrics from Kafka topic(s)" } func (k *Kafka) SetParser(parser parsers.Parser) { k.parser = parser } func (k *Kafka) Start(acc telegraf.Accumulator) error { k.Lock() defer k.Unlock() var consumerErr error k.acc = acc config := consumergroup.NewConfig() config.Zookeeper.Chroot = k.ZookeeperChroot switch strings.ToLower(k.Offset) { case "oldest", "": config.Offsets.Initial = sarama.OffsetOldest case "newest": config.Offsets.Initial = sarama.OffsetNewest default: log.Printf("I! WARNING: Kafka consumer invalid offset '%s', using 'oldest'\n", k.Offset) config.Offsets.Initial = sarama.OffsetOldest } if k.Consumer == nil || k.Consumer.Closed() { k.Consumer, consumerErr = consumergroup.JoinConsumerGroup( k.ConsumerGroup, k.Topics, k.ZookeeperPeers, config, ) if consumerErr != nil { return consumerErr } // Setup message and error channels k.in = k.Consumer.Messages() k.errs = k.Consumer.Errors() } k.done = make(chan struct{}) // Start the kafka message reader go k.receiver() log.Printf("I! Started the kafka consumer service, peers: %v, topics: %v\n", k.ZookeeperPeers, k.Topics) return nil } // receiver() reads all incoming messages from the consumer, and parses them into // influxdb metric points. func (k *Kafka) receiver() { for { select { case <-k.done: return case err := <-k.errs: if err != nil { k.acc.AddError(fmt.Errorf("Consumer Error: %s\n", err)) } case msg := <-k.in: if k.MaxMessageLen != 0 && len(msg.Value) > k.MaxMessageLen { k.acc.AddError(fmt.Errorf("Message longer than max_message_len (%d > %d)", len(msg.Value), k.MaxMessageLen)) } else { metrics, err := k.parser.Parse(msg.Value) if err != nil { k.acc.AddError(fmt.Errorf("Message Parse Error\nmessage: %s\nerror: %s", string(msg.Value), err.Error())) } for _, metric := range metrics { k.acc.AddFields(metric.Name(), metric.Fields(), metric.Tags(), metric.Time()) } } if !k.doNotCommitMsgs { // TODO(cam) this locking can be removed if this PR gets merged: // https://github.com/wvanbergen/kafka/pull/84 k.Lock() k.Consumer.CommitUpto(msg) k.Unlock() } } } } func (k *Kafka) Stop() { k.Lock() defer k.Unlock() close(k.done) if err := k.Consumer.Close(); err != nil { k.acc.AddError(fmt.Errorf("Error closing consumer: %s\n", err.Error())) } } func (k *Kafka) Gather(acc telegraf.Accumulator) error { return nil } func init() { inputs.Add("kafka_consumer", func() telegraf.Input { return &Kafka{} }) }