Camunda BPM PubSub

A community extension for Camunda Platform 7 to integrate Google PubSub in a process and interact with them.

Features

• send pubsub message

Install

We support 2 Versions:

• Version for Spring Boot 2 (last Version 2.7.18, see here) and JDK8+
  • camunda-bpm-pubsub-spring-boot
  • camunda version 7.19.0
• Version for Spring Boot 3 (actual 3.5.6) and JDK17+
  • camunda-bpm-pubsub-spring-boot3
  • camunda version 7.24.0

For Spring Boot

Read these instructions.

For Embedded Process Engine

Add camunda-bpm-pubsub-core as dependency to your application. Using Maven, you have to add the following lines to your POM:

<dependency>
  <groupId>camunda-bpm-examples</groupId>
  <artifactId>camunda-bpm-pubsub-core</artifactId>
  <version>1.0.0-SNAPSHOT</version>
</dependency>

How to use it?

The extension is build on top of the Connectors API and provide some connectors for interacting with Google PubSub. The connectors can be used inside a process as implementation of a service task and are referenced by id. Use the Camunda Modeler to configure it.

<serviceTask id="Task_SendPubSubMessage" name="Send PubSub with Connector" camunda:asyncBefore="true">
  <extensionElements>
    <camunda:connector>
      <camunda:connectorId>pubsub-send</camunda:connectorId>
      <!-- input / output mapping -->
      <camunda:inputOutput>
        <camunda:inputParameter name="projectName">${projectName}</camunda:inputParameter>
        <camunda:inputParameter name="topicName">${topicName}</camunda:inputParameter>
        <camunda:inputParameter name="attributes">${execution.getVariables()}</camunda:inputParameter>
        <camunda:inputParameter name="data">${data}</camunda:inputParameter>
        <camunda:outputParameter name="messageId">${messageId}</camunda:outputParameter>
      </camunda:inputOutput>
    </camunda:connector>
  </extensionElements>
  ...
</serviceTask>

See the connectors user guide how to configure the process engine to use connectors.

Send PubSub

Connector-Id: pubsub-send

Input parameter	Type	Required?
projectName	String	no (read from config)
topicName	String	no (read from config)
attributes	Map<String, Object>	no
data	String	no

Output parameter	Type
messageId	String

How to configure it?

By default, the extension loads the configuration from a properties file pubsub-config.properties on classpath. You can change the lookup path using the environment variable PUBSUB_CONFIG. If you want to look up a file on the classpath, use the classpath: prefix (e.g. classpath:/my-application.config).

An example configuration can look like:

# Activate one of GOOGLE_APPLICATION_CREDENTIALS or PUBSUB_EMULATOR_HOST

# Google PubSub
# GOOGLE_APPLICATION_CREDENTIALS=classpath:your-pubsub-credentials.json

# PubSub Emulator
# PUBSUB_EMULATOR_HOST=0.0.0.0:8085

# PubSub Common
PUBSUB_PROJECT_NAME=your-project-id
PUBSUB_TOPIC_NAME=your-topic-id

Examples

The following examples shows how to use the connectors and services.

• Send Message
  • start process with a list of variables
  • user task to optionally change project/topicName and set the data field (String or JSON)
  • send message to pubsub projectName/topicName using pubsub-send connector
    • attributes = ${execution.getVariables()}
    • data = ${data}
  • user task to review the results, specifically PubSub messageId

OWASP dependency check:

mvn dependency-check:aggregate -Pdependency-check

License

Apache License, Version 2.0