Zeebe EJB Client

Overview

Library

This repository contains a library that enables your JavaEE application as a Client for the Camunda-Platform-8 process engine.

You can reuse your existing JavaEE code and use @ApplicationScoped beans in a job handler as the implementation for BPMN Service tasks and other elements.

The library contains a single startup bean to activate the workers. (ZeebeEjbProcessApplication)

All application scoped beans that are annotated with @JobWorker(type = "mytype") are registered as workers on the Zeebe process engine.

Configuration

The Library uses the Zeebe java client configuration properties.

It reads a file named zeebeClient.properties from the class-path.

Connection properties for Camunda 8 SaaS Cloud cluster:

zeebe.client.cloud.clusterId=xxx
zeebe.client.cloud.clientId=xxx
zeebe.client.cloud.secret=xxx
zeebe.client.cloud.region=bru-2

Connection properties for a local installation with Docker compose:

zeebe.client.gateway.address=localhost:26500
zeebe.client.security.plaintext=true

Other client connection properties are mentioned in this class: io.camunda.zeebe.client.ClientProperties

Example

This repository also contains an example that shows how to reuse existing EJBs in your Zeebe client on an Java-EE Server.

The Zeebe EJB client library registers all methods and classes that are annotated with @JobWorker(taskType="myType").

The Job workers require an @ApplicationScoped for this. See Workers.java.

The Service implementation itself gets injected to the worker. They are annotated with @Stateless. See CustomerService.java

To run the examples, you can deploy it to a running Wildfly server with mvn clean wildfly:deploy. During deployment all workers are registered in the Zeebe process engine and get activated.

Start process instances

The example contains a REST Api to start process instances. Check the content of the package com.camunda.consulting.zeebe_ejb.rest.

To start process instances, use a REST client like curl:

curl for cmd.exe

curl --location --request POST "http://localhost:8080/zeebe-ejb-example-worker-interface/payment/command/start/" ^
--header "Content-Type: application/json" ^
--data-raw "{\"customerId\": \"12\", \"orderTotal\": 39.99, \"creditCardNumber\": \"1234123412341234\", \"cvc\": \"789\", \"expiryDate\": \"07/24\"}"