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https://github.com/cyngn/vertx-kafka

Last synced: 3 months ago
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Host: GitHub
URL: https://github.com/cyngn/vertx-kafka
Owner: cyngn
License: other
Created: 2015-08-15T00:19:22.000Z (about 9 years ago)
Default Branch: master
Last Pushed: 2016-03-21T22:50:05.000Z (over 8 years ago)
Last Synced: 2024-04-10T09:54:52.567Z (7 months ago)
Language: Java
Size: 151 KB
Stars: 30
Watchers: 13
Forks: 11
Open Issues: 3
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
Awesome Lists containing this project

vertx-awesome - kafka - Kafka client for consuming and producing messages. (Integration)
README

        [![Build Status](https://travis-ci.org/cyngn/vertx-kafka.svg?branch=master)](https://travis-ci.org/cyngn/vertx-kafka)

# Vert.x Kafka

The Vert.x kafka library allows asynchronous publishing and receiving of messages on Kafka topic through the vert.x event bus.

####To use this library you must have kafka and zookeeper up and running. Follow instructions at [Kafka quick start guide](http://kafka.apache.org/documentation.html#quickstart)

This is a multi-threaded worker library that consumes kafka messages and then re-broadcast them on an address on the vert.x event bus.

## Getting Started

Add a dependency to vertx-kafka:

```xml

    com.cyngn.vertx

    vertx-kafka

    3.3.0-SNAPSHOT

```

| vertx-kafka | vert.x | kafka |

| ------- | --------------:| --------: |

| 3.3.0-SNAPSHOT | 3.3.0-SNAPSHOT | 0.9.0 |

| 0.4.1   | 3.1.0 | 0.9.0 |

## Consumer

Listening for messages coming from a kafka broker.

### Configuration

```json

{

    "zookeeper.connect" : "",

    "group.id" : "",

    "bootstrap.servers" "",

    "backoff.increment.ms" : "",

    "autooffset.reset" : "",

    "topics" : ["", ""],

    "eventbus.address" : "",

    "consumer.poll.interval.ms" : 

}

```

For example:

```json

{

    "zookeeper.host" : "localhost:2181",

    "group.id" : "testGroup",

    "bootstrap.servers" "localhost:9092",

    "backoff.increment.ms" : "100",

    "autooffset.reset" : "smallest",

    "topics" : ["testTopic"],

    "eventbus.address" : "kafka.to.vertx.bridge",

    "consumer.poll.interval.ms" : 1000

}

```

Field breakdown:

* `zookeeper.connect` a zookeeper connection string of form hostname1:port1,hostname2:port2,hostname3:port3/chroot/path used with your kafka clusters

* `group.id` the kafka consumer group name that will be consuming related to

* `bootstrap.servers` the list of initial kafka hosts to connect to

* `backoff.increment.ms` backoff interval for contacting broker without messages in milliseconds

* `autooffset.reset` how to reset the offset

* `topics` the kafka topics to listen for

* `eventbus.address` the vert.x address to publish messages onto when received form kafka

* `consumer.poll.interval.ms` how often to try and consume messages

For a deeper look at kafka configuration parameters check [this](http://kafka.apache.org/documentation.html) page out.

### Usage

You should only need one consumer per application.

#### Deploy the verticle in your server

```java

vertx = Vertx.vertx();

// sample config

JsonObject consumerConfig = new JsonObject();

consumerConfig.put(ConfigConstants.GROUP_ID, "testGroup");

List topics = new ArrayList<>();

topics.add("testTopic");

consumerConfig.put("topics", new JsonArray(topics));

deployKafka(config);

public void deployKafka(JsonObject config) {

   // use your vert.x reference to deploy the consumer verticle

	 vertx.deployVerticle(MessageConsumer.class.getName(),

      new DeploymentOptions().setConfig(config),

			deploy -> {

   		     if(deploy.failed()) {

        	     System.err.println(String.format("Failed to start kafka consumer verticle, ex: %s", deploy.cause()));

               vertx.close()

               return;

            }

            System.out.println("kafka consumer verticle started");

      }

	);

}

```

#### Listen for messages

```java

vertx.eventBus().consumer(MessageConsumer.EVENTBUS_DEFAULT_ADDRESS,

	message -> {

		   System.out.println(String.format("got message: %s", message.body()))

		   // message handling code

		   KafkaEvent event = new KafkaEvent(message.body());

	 });

```

#### Consumer Errors

You can listen on the address `kafka.producer.error` for errors from the kafka producer.

## Producer

Send a message to a kafka cluster on a predefined topic.

### Configuration

```json

{

    "serializer.class":"",

    "key.serializer":"",

    "value.serializer":"",

    "bootstrap.servers":","

    "default_topic":","

    "eventbus.address":""

    "max.block.ms" : 

}

```

For example:

```json

{

    "serializer.class":"org.apache.kafka.common.serialization.StringSerializer",

    "bootstrap.servers":"localhost:9092",

    "default_topic":"testTopic"

}

```

* `serializer.class` The serializer class for messages

* `key.serializer` The serializer class for keys, defaults to the serializel.class if not set

* `value.serializer` The serializer class for values, defaults to the serializel.class if not set

* `bootstrap.servers` The socket connections for sending the actual data will be established based on the broker information returned in the metadata. The format is host1:port1,host2:port2, and the list can be a subset of brokers or a VIP pointing to a subset of brokers.

* `default_topic` The default topic in kafka to send to

* `eventbus.address` The address to listen to on the event bus, defaults to 'kafka.message.publisher'

* `max.block.ms` How long should the sender wait before getting meta data or time out in ms.

For a deeper look at kafka configuration parameters check [this](https://kafka.apache.org/08/configuration.html) page out.

### Usage

You should only need one producer per application.

#### Deploy the verticle in your server

```java

vertx = Vertx.vertx();

// sample config

JsonObject producerConfig = new JsonObject();

producerConfig.put("bootstrap.servers", "localhost:9092");

producerConfig.put("serializer.class", "org.apache.kafka.common.serialization.StringSerializer");

producerConfig.put("default_topic", "testTopic");

deployKafka(producerConfig);

public void deployKafka(JsonObject config) {

   // use your vert.x reference to deploy the consumer verticle

	 vertx.deployVerticle(MessageProducer.class.getName(),

     new DeploymentOptions().setConfig(config),

		 deploy -> {

   	   if(deploy.failed()) {

         System.err.println(String.format("Failed to start kafka producer verticle, ex: %s", deploy.cause()));

          vertx.close()

          return;

       }

       System.out.println("kafka producer verticle started");

   });

}

```

#### Send message to kafka topic

```java

KafkaPublisher publisher = new KafkaPublisher(vertx.eventBus());

// send to the default topic

publisher.send("a test message on a default topic");

// send to a specific topic

publisher.send("SomeSpecialTopic", "a test message on a default topic");

// send to a specific topic with custom key

publisher.send("SomeSpecialTopic", "aUserId", "a test message on a default topic");

// send to a specific topic and partition

publisher.send("SomeSpecialTopic", "", 5, "a test message on a default topic");

```

#### Producer Errors

You can listen on the address `kafka.producer.error` for errors from the kafka producer.

### Test setup

* cd [yourKafkaInstallDir]

* bin/zookeeper-server-start.sh config/zookeeper.properties

* bin/kafka-server-start.sh config/server.properties

* bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 8 --topic [yourTestTopic]

* bin/kafka-console-producer.sh --broker-list localhost:9092 --topic [yourTestTopic]

* bin/kafka-console-consumer.sh --zookeeper localhost:2181 --topic [yourTestTopic]