Turning a Node.js script into a Firebase Function

Question

I have a node.js script that works perfectly when running from command line, but when I try to use it as a function fails.

const functions = require('firebase-functions');
exports.dailyUpdate = functions.pubsub.schedule('5 5 * * *')
.onRun((context) => {
db.collection("meters")
  .get()
  .then(function (querySnapshot) {
    querySnapshot.forEach(function (doc) {
      let mtrList = meterlist.push([
        doc.id,
      ]);
      return true;
    });

    meterlist
      .forEach(function (obj) {
        var meterid = obj[0];
        var meterdata;
        var history = [];

        axios
          .get(url)
          .then((response) => {
            metername = meterid.toString();
            meterdata = response.data.meterdata;
            if (meterdata) {
              meterdata.forEach(function (obj) {
                let datadate = obj.stamp.substring(0, 10);
                let datatime = obj.stamp.substring(11, 13);
                let data = obj.data;
                history.push({
                  metername: metername,
                  datadate: datadate,
                  datatime: datatime,
                  data: data,
                });
              });

let todayUpdate = runCalculations(history);

               updateDB(todayUpdate);
            }
            return Promise.resolve("done!");
          })
          .catch(function (error) {
            console.log(error);
          });
        return true;
      })
    return true;
  })
  .catch(function (error) {
    console.log(error);
  });

  response.send("Updated!!");
});

I'm sure I'm doing something wrong, but when I, for example put the require s in the code section,

const axios = require("axios");
const firebase = require("firebase");
require("firebase/firestore");
var moment = require("moment");
var _ = require("lodash");
var Promise = require("promise");

doesn't run because it doesn't know where axios is. When I place them before the exports... below the const functions = require('firebase-functions');I get different errors, including: ""Detailed stack trace: Error: Cannot find module 'axios'" // Provided module can't be loaded. // Could not load the function, shutting down. // Function cannot be initialized. "

The script itself runs a querySnapshot from a Firestore db, parses the results, calls an api through axios , runs a bunch of calculations, and then updates the db with the updated results. And I want this to run at 5:05AM every day.

I did not make any changes to the actual code of the script besides including the above exports code.

What am I missing?

Answer 1

When you deploy a Cloud Function, the node_modules directory needs to be populated , or you need to use Webpack (or some such) to include the dependencies. Firebase Deploy seems to essentially Zip the entire directory, upload and then run it in the cloud to deploy the specific function as called out in the entry point. All the dependencies need to be present in one form or another.

I happen to use a slightly unconventional approach to this, but the net-net is that Cloud Functions ARE NOT just another host to deploy to - they have quite specific formats and functions you need to follow. Read the documentation. Read it again. Walk through the samples. Then remember the samples are the simplest approach, but not the only approach.