How to correctly resume state?

Hello, I created small sample diagram and script, that must resume execution of diagram if it unexpectedly stops. But in fact it executes only last block and stops whole script. Please help, what I’m doing wrong?

Normal execution, without interrupt ( with debug )

~ node index.js
START Test process
START Start
START Task A
START Task B
Waiting Task B for 5 seconds...
START Parallel 2
Resume Task B!
START Task C
Script completed

Execution with interrupt on Task B ( with debug ) :

~ node index.js
START Test process
START Start
START Task A
START Task B
Waiting Task B for 5 seconds...
START Parallel 2
^C

~ node index.js
Resuming saved state
START Task B
Waiting Task B for 5 seconds...
Resume Task B!
START Parallel 2

Code: index.js and Services.json

Diagram: diagram_1.bpmn

engine.getState() output when I interrupted execution by ^C: state.json

[paed01]

I have tried to make sure there is a state to save when listening on start, e.g:

listener.on('start', () => {})`.

@NeonXP: Can you update the engine with npm i bpmn-engine@rc and try again?

[paed01]

@christopherRiddersater I would, imho, consider a message broker, e.g. RabbitMQ. When the listener emits wait or start (or ends) a message is published with the state. It is non-interrupting and the state is saved even if the instance is abruptly terminated.

Regarding states, what I’m trying to argue is that the diagram designer (or devops) knows best when a recoverable state is in place. To facilitate this the bpmn-engine could expose the activity properties (defined in the modeler), as such:

const amqp = require('exp-amqp-connection');
const connection = amqp({
  exchange: 'bpmn-engine',
  url: 'amqp://localhost'
});

//...

listener.on('start', (activity) => {
  // camunda modeler - select activity - tab Extensions + Add Property
  if (activity.properties.recoverableState) {
    return connection.publish('state.recoverable', engine.getState());
  }
  return connection.publish('state', engine.getState());
});

engine.once('end', () => {
  connection.publish('bpmn-engine', 'end', engine.getState());
});

Would that help? (#20?)