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Kafka Producer and Counsmer

Prerequisites

  1. Run a local Kafka server following the steps (1 and 2) from here: https://kafka.apache.org/quickstart

Steps

  1. Create a project kafka_project
  2. Then create a JavaScript service named my_kafka_handler.js
  3. Replace the service code with the following content:

Handler

exports.onMessage = function(message) {
    console.log("Hello from My Kafka Listener! Message: " + message);
};

exports.onError = function(error) {
    console.error("Error from My Kafka Listener! Error: " + error);
};
  1. Then create a Kafka Consumer named my_kafka_consumer.js
  2. Replace the file content with the following code:
var consumer = require("kafka/consumer");
consumer.topic("topic1", "{}").startListening("kafka_project/my_kafka_handler", 1000);
  1. Then create another back-end service which will play the role of a trigger my_kafka_producer.js
  2. Replace the trigger content with the following code:
var producer = require("kafka/producer");
producer.topic("topic1", "{}").send("key1", "value1");
  1. Publish the project
  2. Select the my_kafka_producer.js file in the Workspace view to be able to trigger the invocation of this service via the Preview view
  3. In the Console view you should see the following lines:

    2020-11-01 23:33:54.272 [INFO ] [Thread-275] o.e.dirigible.api.v3.core.Console - Hello from My Kafka Listener! Message: {"topic":"topic1","partition":0,"offset":29,"timestamp":1604266434251,"timestampType":"CREATE_TIME","serializedKeySize":4,"serializedValueSize":6,"headers":{"headers":[],"isReadOnly":false},"key":"key1","value":"value1","leaderEpoch":{"value":0}}

Note: the log messages in the Console view are in a reverse order - the newest are on top


For more information, see the API documentation.

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