Camunda 8 with Spring Boot example

For this example, I am using the camunda-community-hub approach as described here.

Prerequisite

The example requires a Camunda account with access to the Camunda Platform Console.

How to run

Maven

Note: You can only run it if the credentials have been filled in correctly! See Modify application.properties

./mvnw package spring-boot:run

After that instances can be started with the following variable content:

{
  "reference": "C8_12345",
  "amount": 100.00,
  "cardNumber": "1234567812345678",
  "cardExpiry": "12/2023",
  "cardCVC": "123"
}

See the official guide for further information.

The terminal will show the following output:

2023-02-10 10:43:00.167 TRACE 31393 --- [pool-4-thread-1] d.k.c.job.CreditCardJobWorker            : start Job for Bpmn-id: paymentProcess
2023-02-10 10:43:00.168 TRACE 31393 --- [pool-4-thread-1] d.k.c.service.CreditCardService          : Charging Credit Card: 1234567812345678
2023-02-10 10:43:00.168  INFO 31393 --- [pool-4-thread-1] d.k.c.service.CreditCardService          : Credit Card Data: 
2023-02-10 10:43:00.168  INFO 31393 --- [pool-4-thread-1] d.k.c.service.CreditCardService          : - reference: C8_12345
2023-02-10 10:43:00.169  INFO 31393 --- [pool-4-thread-1] d.k.c.service.CreditCardService          : - amount: 100.0
2023-02-10 10:43:00.169  INFO 31393 --- [pool-4-thread-1] d.k.c.service.CreditCardService          : - cardExpiry: 12/2023
2023-02-10 10:43:00.169  INFO 31393 --- [pool-4-thread-1] d.k.c.service.CreditCardService          : - cardCVC: 123

Implementation tips

Modify application.properties

Fill the application.properties-File with your individual values. Client credentials can be generated in the Camunda 8 Console. See Set up client connection credentials for further information.

zeebe.client.cloud.region=<your region>
zeebe.client.cloud.clusterId=<your cluster id>
zeebe.client.cloud.clientId=<your client id>
zeebe.client.cloud.clientSecret=<your client secret>

Modify pom.xml

Add additional dependencies in your pom.xml:

...
<properties>
    ...
    <spring-zeebe.version>8.1.5</spring-zeebe.version>
</properties>
        ...
<dependencies>
...
<dependency>
    <groupId>io.camunda</groupId>
    <artifactId>spring-zeebe-starter</artifactId>
    <version>${spring-zeebe.version}</version>
</dependency>
<dependency>
    <groupId>io.camunda</groupId>
    <artifactId>spring-zeebe-test</artifactId>
    <version>${spring-zeebe.version}</version>
    <scope>test</scope>
</dependency>
</dependencies>
        ...

Modify Application-class

import io.camunda.zeebe.spring.client.EnableZeebeClient;
import io.camunda.zeebe.spring.client.annotation.Deployment;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@EnableZeebeClient
@SpringBootApplication
@EnableScheduling
@Deployment(resources = "classpath*:*.bpmn")
public class ExampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(ExampleApplication.class, args);
    }

}

Add a new bpmn file

Add your .bpmn file to resources.

See CreditCardProcess.bpmn for example.

Create a new worker

import io.camunda.zeebe.client.api.response.ActivatedJob;
import io.camunda.zeebe.spring.client.annotation.JobWorker;
import io.camunda.zeebe.spring.client.annotation.Variable;
import io.camunda.zeebe.spring.client.annotation.VariablesAsType;
import org.springframework.stereotype.Component;

@Component
public class ExampleWorker {

    // simple worker
    @JobWorker(type = "exampleType")
    public void handle(final ActivatedJob job) {
        // implement your code here
    }

    // worker with 1 variable
    @JobWorker(type = "exampleType2")
    public void handle2(final ActivatedJob job, @Variable String variableName) {
        // implement your code here
    }

    // worker with x variables as object
    @JobWorker(type = "exampleType3")
    public void handle3(final ActivatedJob job, @VariablesAsType MyCustomObject customObject) {
        // implement your code here
    }

}

Testing

import io.camunda.zeebe.client.ZeebeClient;
import io.camunda.zeebe.client.api.response.ProcessInstanceEvent;
import io.camunda.zeebe.process.test.api.ZeebeTestEngine;
import io.camunda.zeebe.spring.test.ZeebeSpringTest;
import org.junit.jupiter.api.Test;
import org.mockito.Mockito;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import static io.camunda.zeebe.process.test.assertions.BpmnAssert.assertThat;
import static io.camunda.zeebe.spring.test.ZeebeTestThreadSupport.waitForProcessInstanceCompleted;

@SpringBootTest
@ZeebeSpringTest
class ExampleTest {

    @Autowired
    private ZeebeClient zeebe;

    @Autowired
    private ZeebeTestEngine zeebeTestEngine;

    @Test
    void creditCardShouldBeCharged() {
        MyObject myObjectVariables = new MyObject();

        // start a process instance
        ProcessInstanceEvent processInstance = zeebe.newCreateInstanceCommand() //
                .bpmnProcessId("paymentProcess").latestVersion() //
                .variables(myObjectVariables) //
                .send().join();

        // wait for process completion
        waitForProcessInstanceCompleted(processInstance);

        // assert that process is finished and my EndEvent is passed
        assertThat(processInstance)
                .hasPassedElement("My_EndEvent_Id")
                .isCompleted();
    }
}