EMQX - Kafka 插件（一）

准备

• EMQX - 导读

• EMQX - 源码阅读（六）

• emqx_plugin_kafka

emqx_plugin_kafka

Kafka plugin for EMQX >= V5.4.0

Usage

Release

> git clone https://github.com/jostar-y/emqx_plugin_kafka.git
> cd emqx_plugin_kafka
> make rel
_build/default/emqx_plugrel/emqx_plugin_kafka-<vsn>.tar.gz

Config

Explain

> cat priv/emqx_plugin_kafka.hocon
plugin_kafka {
  // required
  connection {
    // Kafka client id: "emqx_plugin:kafka_client:${client_id}"
    // optional   default:"emqx_plugin:kafka_client:emqx_plugin_kafka_connection"
    client_id = "kafka_client"
    // Kafka address.
    // required
    bootstrap_hosts = ["10.3.64.223:9192", "10.3.64.223:9292", "10.3.64.223:9392"]

    // Reference type: kpro_connection:config().
    // https://github.com/kafka4beam/kafka_protocol/blob/master/src/kpro_connection.erl
    // optional   default:5s
    connect_timeout = 5s
    // enum: per_partition | per_broker
    // optional   default:per_partition
    connection_strategy = per_partition
    // optional   default:5s
    min_metadata_refresh_interval = 5s
    // optional   default:true
    query_api_versions = true
    // optional   default:3s
    request_timeout = 3s
    sasl {
      // enum:  plain | scram_sha_256 | scram_sha_512
      mechanism = plain
      username = "username"
      password = "password"
    }
    ssl {
      enable = false
    }

    //Emqx resource opts.
    // optional   default:32s
    health_check_interval = 32s
  }

  // optional
  producer {
    // Most number of bytes to collect into a produce request.
    // optional   default:896KB
    max_batch_bytes = 896KB
    // enum:  no_compression | snappy | gzip
    // optional   default:no_compression
    compression = no_compression
    // enum:  random | roundrobin | first_key_dispatch
    // optional   default:random
    partition_strategy = random

    // Encode kafka value.
    // enum:  plain | base64
    // optional   default:plain
    encode_payload_type = plain
  }

  // required
  hooks = [
    {
      // Hook point.
      // required
      endpoint = message.publish
      // Emqx topic pattern.
      // 1. Cannot match the system message;
      // 2. Cannot use filters that start with '+' or '#'.
      // message required
      filter = "test/#"
      // Kafka topic, must be created in advance in Kafka.
      // required
      kafka_topic = emqx_test
      // Matching template, value = ${.} indicates that all keys match
      // optional default:{timestamp = "${.timestamp}", value = "${.}",key = "${.clientid}"}
      kafka_message = {
        timestamp = "${.timestamp}"
        value = "${.}"
        key = "${.clientid}"
      }
    }
  ]
}

Some examples in the directory priv/example/.

Hook Point

endpoint	filter
client.connect	/
client.connack	/
client.connected	/
client.disconnected	/
client.authenticate	/
client.authorize	/
client.authenticate	/
client.check_authz_complete	/
session.created	/
session.subscribed	/
session.unsubscribed	/
session.resumed	/
session.discarded	/
session.takenover	/
session.terminated	/
message.publish	required
message.delivered	required
message.acked	required
message.dropped	required

Path

• Default path： emqx/etc/emqx_plugin_kafka.hocon
• Attach to path: set system environment variables export EMQX_PLUGIN_KAFKA_CONF="absolute_path"