App Engine doesn't recognize a JSON file

Question

I'm new in this kind of platform (cloud) and I have a problem with App Engine.

I have the following project structure in App Engine:

• Root
  • nodejs-docs-samples
  • src
  • be-nodejs-piloto
    • node_modules
    • api.js (api post uri)
    • app.js (main)
    • app.yaml
    • datastore-quickstart.json (datastore key client)
    • package-lock.json
    • package.json
  • vibrant-tree-191664

app.yaml (content)

runtime: nodejs
  env: flex

manual_scaling:
  instances: 1
resources:
  cpu: 1
  memory_gb: 0.5
  disk_size_gb: 10

api.js (content)

'use strict';

// Load libs.
var express  = require('express');
var router   = express.Router();

const Datastore = require('@google-cloud/datastore'); // Imports the Google Cloud client lib

// Your Google Cloud Platform project ID
const projectId   = 'datastore-quickstart-191515';
const keyFilename = '/home/testcloud99/src/be-nodejs-piloto/datastore-quickstart-5672f2cde8ca.json';

console.log('keyFilename:' + keyFilename);

// Creates a client
const datastore = new Datastore({
    projectId: projectId,
    keyFilename: keyFilename
  });


router.route('/api/piloto')

    .post(function (req, res)
    {
        console.log('method: POST');

        // Read params
        var pMsgId   = req.body.msgId;

        const query = datastore.createQuery('MyEntity');
        query.filter('msgId', '=', pMsgId);

        // exec query
        datastore
            .runQuery(query)
            .then(results => {

                //OK
                return res.status(200).jsonp({
                    "piloto":
                    {
                        "code" : 0,
                        "desc" : "ok",
                    }
                });

        })
        .catch(err => {
            console.error('ERROR:', err);
            return res.status(200).jsonp({
                "piloto":
                {
                    "code" : 1,
                    "desc" : "error",
                    "errorMessage" : err.message
                }
                });
        });

    });

module.exports = router;

So, when I send a POST message (using soapUI), I get this response:

{"piloto": {
   "code": 1,
   "desc": "error",
   "errorMessage": "ENOENT: no such file or directory, open '/home/testcloud99/src/be-nodejs-piloto/datastore-quickstart-5672f2cde8ca.json'"
}}

I guess App Engine isn't recognizing that JSON file but I don't know why. Any kind of configuration that should be done?

PD. I have also tried setting "GOOGLE_APPLICATION_CREDENTIALS" environment variable with "Datastore" constructor without "keyFilename" parameter and I got same result.

Hope you can help me.

Regards.

Answer 1

The problem is this definition:

const keyFilename = '/home/testcloud99/src/be-nodejs-piloto/datastore-quickstart-5672f2cde8ca.json';

You can't use absolute file paths from your local machine, that filesystem doesn't exist on the cloud machine. You have to use paths relative to your appplication's directory, which is the one where the application's app.yaml file exists, in your case /home/testcloud99/src/be-nodejs-piloto, try this instead:

const keyFilename = 'datastore-quickstart.json';

Note that I updated the filename as well as from your directory structure there is no datastore-quickstart-5672f2cde8ca.json file in there. Check that it's indeed the file you desire.