Add support for lz4 compression to kafka output (#4492)

Author: danielnelson

plugins/outputs/kafka/README.md

@@ -10,17 +10,23 @@ This plugin writes to a [Kafka Broker](http://kafka.apache.org/07/quickstart.htm
   ## Kafka topic for producer messages
   topic = "telegraf"
 
-  ## Optional client id
+  ## Optional Client id
   # client_id = "Telegraf"
 
+  ## Set the minimal supported Kafka version.  Setting this enables the use of new
+  ## Kafka features and APIs.  Of particular interested, lz4 compression
+  ## requires at least version 0.10.0.0.
+  ##   ex: version = "1.1.0"
+  # version = ""
+
   ## Optional topic suffix configuration.
   ## If the section is omitted, no suffix is used.
   ## Following topic suffix methods are supported:
   ##   measurement - suffix equals to separator + measurement's name
   ##   tags        - suffix equals to separator + specified tags' values
   ##                 interleaved with separator
 
-  ## Suffix equals to "_" + measurement's name
+  ## Suffix equals to "_" + measurement name
   # [outputs.kafka.topic_suffix]
   #   method = "measurement"
   #   separator = "_"

plugins/outputs/kafka/kafka.go

@@ -38,6 +38,8 @@ type (
 		// MaxRetry Tag
 		MaxRetry int
 
+		Version string `toml:"version"`
+
 		// Legacy TLS config options
 		// TLS client certificate
 		Certificate string
@@ -74,6 +76,12 @@ var sampleConfig = `
   ## Optional Client id
   # client_id = "Telegraf"
 
+  ## Set the minimal supported Kafka version.  Setting this enables the use of new
+  ## Kafka features and APIs.  Of particular interested, lz4 compression
+  ## requires at least version 0.10.0.0.
+  ##   ex: version = "1.1.0"
+  # version = ""
+
   ## Optional topic suffix configuration.
   ## If the section is omitted, no suffix is used.
   ## Following topic suffix methods are supported:
@@ -191,6 +199,14 @@ func (k *Kafka) Connect() error {
 	}
 	config := sarama.NewConfig()
 
+	if k.Version != "" {
+		version, err := sarama.ParseKafkaVersion(k.Version)
+		if err != nil {
+			return err
+		}
+		config.Version = version
+	}
+
 	if k.ClientID != "" {
 		config.ClientID = k.ClientID
 	} else {