Migrate from Camunda 7

This guide walks you through migrating an existing Camunda Platform 7 application to Priostack. Most migrations can be completed in a day for small projects, or a week for large enterprise deployments.

Section 1: What's Compatible

Priostack runs BPMN 2.0, so your existing process diagrams transfer with changes limited to extensions. What runs on the hosted service:

• Tasks, gateways (exclusive, parallel, inclusive, event-based), embedded sub-processes, and event sub-processes with a timer start event (the other start events deploy but have no hosted trigger)
• Call activities that name, in the standard calledElement attribute, a process deployed before the caller (otherwise the call is offered to workers as a job of type callActivity:<name>)
• Sequence flow conditions using FEEL expressions
• Timer intermediate and boundary events with an ISO 8601 duration or date. A timeCycle is refused at deploy, and a timer start event does not schedule anything: instances start through the API
• Compensation handlers, run in reverse order when the model throws compensation explicitly
• Multi-instance tasks (parallel and sequential)
• DMN 1.3 decision tables, evaluated inline by a business rule task

What is accepted at deploy but has no hosted trigger today: message and signal catch events and receive tasks wait as ordinary worker jobs (there is no message or signal API, see the table below), and error and escalation boundary events do not fire from worker code, because the REST API has no call for a worker to throw a BPMN error.

Section 2: What's Different

Section 3: Migration Steps

Step 1: Export Your BPMN Files

From Camunda Modeler or Cockpit, export all your BPMN files as .bpmn XML files. Keep DMN files too.

Step 2: Remove Camunda-Specific Extensions

Open each BPMN file and replace Camunda 7 extension elements. The Priostack snippets are fragments: paste them inside a <definitions> element that declares xmlns:zeebe="http://camunda.org/schema/zeebe/1.0".

<serviceTask id="validateOrder"
  camunda:class="com.example.ValidateOrderDelegate"
  camunda:asyncBefore="true" />

<serviceTask id="validateOrder"
             name="Validate Order">
  <extensionElements>
    <zeebe:taskDefinition
      type="validate-order"
      retries="3" />
  </extensionElements>
</serviceTask>

<userTask id="review"
  camunda:assignee="${reviewer}"
  camunda:candidateGroups="managers" />

<userTask id="review" name="Review Order" />

<!-- Assignment is not read from the model.
     Assign or claim through the API:
     POST /api/v1/tasks/{id}/assign
     POST /api/v1/tasks/{id}/claim -->

Step 3: Rewrite Java Delegates as Workers

For each Java Delegate class, create an equivalent external worker in Go, Python, or JavaScript. See the Workers Guide.

@Component
public class ValidateOrderDelegate
    implements JavaDelegate {

  @Autowired
  private OrderService orderService;

  @Override
  public void execute(DelegateExecution exec) {
    String orderId = (String) exec
        .getVariable("orderId");
    boolean valid = orderService.validate(orderId);
    exec.setVariable("orderValid", valid);
  }
}

func processJob(job Job) (map[string]interface{}, error) {
  orderId, _ := job.Variables["orderId"].(string)

  // Call your existing service
  valid, err := orderService.Validate(orderId)
  if err != nil {
    return nil, err
  }
  return map[string]interface{}{
    "orderValid": valid,
  }, nil
}

Step 4: Update API Calls

POST /engine-rest/process-definition
     /key/order-processing/start
{
  "variables": {
    "orderId": { "value": "123", "type": "String" }
  }
}

POST /api/v1/process-instances
X-API-Key: your_key
{
  "bpmnProcessId": "order-processing",
  "variables": {
    "orderId": "123"
  }
}

Step 5: Deploy and Test

# Deploy your updated BPMN (free on this route; 200 with a deployments array)
curl -X POST "https://priostack.com/api/v1/process-definitions?resourceName=order-processing.bpmn" \
  -H "X-API-Key: your_key" \
  -H "Content-Type: application/xml" \
  --data-binary @order-processing.bpmn

# Start your workers
export PRIOSTACK_API_KEY=your_key
go run worker.go

# Start a test instance (201, costs 1 credit)
curl -X POST https://priostack.com/api/v1/process-instances \
  -H "X-API-Key: your_key" \
  -H "Content-Type: application/json" \
  -d '{"bpmnProcessId":"order-processing","variables":{"orderId":"TEST-001"}}'

Section 4: Feature Mapping