From BPMN Sketch to Camunda-Ready Model: User and Service Tasks
A BPMN sketch is fine for people, but a process engine like Camunda has to run it. Turn plain tasks into user, service and send tasks, name every end by its result, and export the BPMN file, all in the free bpmn.io modeler.
Step by step
Sketch vs engine
- Engine-ready BPMN. Your BPMN sketch makes sense to people. But when an engine like Camunda runs the process, it needs to know who does each task and how each path ends. Here's the refund process we'll make engine-ready.
- New diagram. Start a new diagram in bpmn.io and name the start event refund requested.
The sketch
- Sketch it. First, sketch the flow with plain tasks. Click the start event and add a task from its menu. Check refund. Then a gateway that asks refund approved? If yes, pay the refund. Add the task and label its arrow yes. Then tell the customer. Add one more task. End the path. In a quick sketch, people often just write done. If no, drag an end event from the gateway's menu to the space below it. Name it refund rejected, and label the arrow no.
Task types
- User task. Now make it engine-ready. A plain task tells the engine nothing. Click check refund, open the wrench, and pick user task. The little person means a human does it, so it lands in someone's task list.
- Service task. A system pays the refund, not a person. Make pay refund a service task. The gears mean the engine calls another system to do the work.
- Send task. Tell customer sends a message out of the process. Make it a send task, the filled envelope.
Clear ends
- Name the ends. Done is too vague. The engine reports which end each case reached, so name the result. Double-click the end event and type refund paid.
Export
- Export. Now click the BPMN button at the bottom left. It downloads the model as a BPMN file, the file an engine like Camunda reads and runs.
- The ready model. Click away to see it all. A user task, a service task, a send task, labelled gateway arrows, and two ends named by their result.
Recap
- The rules. So, before a process runs in an engine, give every task a type: user task for people, service task for systems, send task for messages. Label every gateway arrow and name every end by its result.
