App Engine doesn't recognize a JSON file - node.js

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.

Answer 2

it would be good to point out that in the official Google documentation this year (2021) it says that the default would be Mac/linux
export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"
and Windows:
For PowerShell:
$env:GOOGLE_APPLICATION_CREDENTIALS="KEY_PATH"
Replace KEY_PATH with the path of the JSON file that contains the service account key.
Example:
$env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\service-account-file.json"
For command prompt:
set GOOGLE_APPLICATION_CREDENTIALS=KEY_PATH
Replace KEY_PATH with the path of the JSON file that contains the service account key.
based on the model of the official documentation we have this example
// Imports the Google Cloud client library
const {Datastore} = require('#google-cloud/datastore');
// Creates a client
const datastore = new Datastore();
async function quickstart() {
// The kind for the new entity
const kind = 'Task';
// The name/ID for the new entity
const name = 'sampletask1';
// The Cloud Datastore key for the new entity
const taskKey = datastore.key([kind, name]);
// Prepares the new entity
const task = {
key: taskKey,
data: {
description: 'Buy milk',
},
};
// Saves the entity
await datastore.save(task);
console.log(`Saved ${task.key.name}: ${task.data.description}`);
}
quickstart();