bpmn-engine is not waiting for async calls

[ermarkar]

I have integrated bpmn-engine with ding-dong agi server.

So in flow i mentioned voice files to play

const listener = new EventEmitter();
listener.on('activity.start', async (elementApi, engineApi) => {
   console.log(elementApi.name);
   await streamFile(voiceFilePath)
});

listener.on('activity.wait', (elemntApi, instance) => {
  console.log(`${elemntApi.type} <${elemntApi.id}> of ${instance.name} is waiting for input`);
  elemntApi.signal('don´t wait for me');
});

await engine.execute({
  listener
});

it is logging all the activity names but it is not playing any file using streamFile, even i am using await.

how can i solve this?

[paed01]

An eventhandler is immediate and will not be awaited. If you want to postpone the execution on start you have to use an extension.

[ermarkar]

Thanks for the great library and quick response, but still bit confused.

so instead of listener for activity.start, i should use extensions? like this

const engine = new Engine({
  name: 'My IVR listener',
  source,
  extensions: {
    myExtentension
  }
});

const listener = new EventEmitter();

listener.on('wait', (elementApi) => {

  // async tasks here

  elementApi.signal();
});

engine.execute({
  listener
});

function myExtentension(activity) {
  activity.on('start', async () => {
    // await -- async task 1 -> getting data from server
    // await -> asyync task2 -> streaming file 
    // await -> async task 3 

    // do i need to publish this????
    activity.broker.publish('format', 'run.form', {form});
  });
}

and for wait listener would work? or for that i need to listen the same wait insside myExtension?

[paed01]

Have a look at this test but you will replace the getForm with your agi-api-call.

The activity execution will wait until the endRoutingKey is published. You decide what to pass when publishing the format end routing key. The content will be added to the message content on the next step in the execution - i.e. the lifecycle of an activity.

[ermarkar]

bpmnEngine = Engine({
        name: 'IVR calls Listener',
        extensions: {
          saveToResultVariable,
          myExt(activity) {

            const endRoutingKey = 'run.form.end';

            activity.on('enter', async (elementApi, engineApi) => {
              console.log("myext:", activity.name);
              await FlowActivityHandler.onStart(elementApi, engineApi);
              activity.broker.publish('format', endRoutingKey, { "helloKey": "hello" });
            });
          }
        }
      });

but still it is not waiting and not playing the files, am i still missing something?

[ermarkar]

i added

activity.on('enter', async (elementApi, engineApi) => {
              console.log("myext:", activity.name);
              activity.broker.publish('format', 'run.form.start', { endRoutingKey });

              try {
                await FlowActivityHandler.onStart(elementApi, engineApi);
              } catch (err) {
                console.log("file: agi-server.js:117 ~ activity.on ~ err:", err);
              }
              console.log("firing activing end ->>>>>>>>> ")
              activity.broker.publish('format', endRoutingKey, { "helloKey": "hello" });
            });

now this is behaving in sync manner, but it got stuck on bpmn:IntermediateThrowEvent

fileToPlay -> welcome firing activing end ->>>>>>>>> element api ------ undefined bpmn:IntermediateThrowEvent element api ------ undefined bpmn:IntermediateThrowEvent firing activing end ->>>>>>>>>

its not moving further

[paed01]

Perhaps the referenced test can shed some light on the issue.

[ermarkar]

@paed01 thanks for the help, but still I am facing same, I have used this now

function bpmnActivityHandler(bpmnActivity) {
  if (bpmnActivity.type === 'bpmn:Process') return;
  return {
    activate() {
      bpmnActivity.on('enter', async (elementApi, engineApi) => {
        bpmnActivity.broker.publish('format', 'run.format.start', { endRoutingKey: 'run.format.complete' });
        try {
          await FlowActivityHandler.onStart(elementApi, engineApi);
        } catch (err) {
          // end call
        }
        bpmnActivity.broker.publish('format', 'run.format.complete', { msg: "testmm" });
      }, { consumerTag: 'format-on-enter' });
    },
    deactivate() {
      bpmnActivity.broker.cancel('format-on-enter');
    },
  };
}

still it got stuck on bpmn:IntermediateThrowEvent. though there are other bpmn:IntermediateThrowEvent before the first streamFile that is working fine means it proceeds

this is under subprocess like this.. it is not moving to other subprocess

ebfore greetings there are service subprocess that too containes bpmn:IntermediateThrowEvent but it works for that, greeting is the first subprocess having files to play

Am i still missing something?

[ermarkar]

i added this and it is proceeding all the elements now

function bpmnActivityHandler(bpmnActivity) {
  const eventsToIgnore = ['bpmn:Process', 'bpmn:SubProcess', 'bpmn:IntermediateThrowEvent'];
  if (eventsToIgnore.includes(bpmnActivity.type)) {
    return;
  }
  return {
    activate() {
      bpmnActivity.on('enter', async (elementApi, engineApi) => {

and the bpmn:UserTask that needs user input I am handling using listener like this

// waiting for user input
    activityListener.on("wait", onWait);

    await bpmnEngine.execute({
      listener: activityListener,

is this correct?

[paed01]

If it works I guess so :)

Nice work.

[ermarkar]

Thanks for the help and clues!!! is there any document for this..

bpmnActivity.broker.publish('format', 'run.format.start', { endRoutingKey: 'run.format.complete' });

like all the elements in this are still confusing, what are other event that can be published etc

thanks again :)