Dialogflow-fulfillment-nodejs: Agent responses (erratically) don't show

[sarupbanskota]

I've got the following intent handler:

  async function expenseLogHandler(agent) {
    const value = agent.parameters["value"];
    const currency = agent.parameters["currency"] || "SGD";
    const timestamp = Number(new Date());

    const payload = {};
    payload.quick_replies = [{
      content_type: 'text',
      payload: 'log more',
      title: 'log more'
    }]

    try {
      const expense = await db.collection("expenses").add({
        value, currency, timestamp
      });
      console.log('Logged expense: ', expense);
      payload.text = `ok done: ${currency} ${value} added`;
      // Remove and move this outside of try/catch sometime
      agent.add(new Payload(agent.FACEBOOK, payload))
    } catch(err) {
      console.error('Error logging expense: ', err);
      payload.text = `Something went wrong: ${err.toString()}`;
      // Remove and move this outside of try/catch sometime
      agent.add(new Payload(agent.FACEBOOK, payload))
    }
  }

Every single time it's invoked, an expense is instantly being created in Cloud Firestore - it reflects within Firebase and also on the Cloud Function's logs.

However the Facebook message payload erratically doesn't show 30% of the time (there is no error, and the expense is _always_ created), just the error doesn't show.

What could I be doing wrong?

[nathanjliu]

It seems like you're hitting the 5 second limit Dialogflow has for a response to be returned. If nothing is returned in 5 seconds, the default response will be sent but the function will finish running in the background.

[matthewayne]

@nathanjliu's assessment seems reasonable @sarupbanskota can you confirm this is causing your issue?

[sarupbanskota]

That's right @nathanjliu and @matthewayne, appears to be the 5s limit.

I was aware of the DF limit itself, but didn't realise how/when the cold boot problem would affect a cloud function. So while my original question is answered, I'm curious if there's an easy way to check what node dependency versions might be cached within cloud functions infra?

---

For future reference for anyone else who runs into a similar issue, I found the following helpful:

1. https://cloud.google.com/functions/docs/bestpractices/tips
2. https://medium.com/@duhroach/improving-cloud-function-cold-start-time-2eb6f5700f6