Getting a token with google service account (jwt)

I try to connect to the firebase REST API :

so I need a google oauth2 access tokens. Google provide 3 sets of client library, JAVA, NODE.JS and PYTHON
of course no coldfusion.
I found this project :
but it stand : “The token can be your secret, but is less secure than generating a JWT that expires or based on a $uid with a library like the awesome cf-simple-jwt”
of course the awesome library cf-jwt-simple is far to be as simple as the NODE.JS version of the library …:

Anyone managed to get an access token from a google service account with a json file ? a really need an example …

Thanks for your help

PS : the solution with the node.js lib is straightforward :

var google = require("googleapis");

// Load the service account key JSON file.
var serviceAccount = require("./myjsonfile.json");

// Define the required scopes.
var scopes = [

// Authenticate a JWT client with the service account.
var jwtClient = new google.auth.JWT(

// Use the JWT client to generate an access token.
jwtClient.authorize(function(error, tokens) {
  if (error) {
    console.log("Error making request to generate access token:", error);
  } else if (tokens.access_token === null) {
    console.log("Provided service account does not have permission to generate access tokens");
  } else {
    var accessToken = tokens.access_token;
    console.log("Access tokens "+ accessToken);
    // See the "Using the access token" section below for information
    // on how to use the access token to send authenticated requests to
    // the Realtime Database REST API.

@Stephane_MERLE, did you have any luck with this? I’m trying to do the same as what you are trying to do, with google cloud printing services.

any reason why you didn’t use one the libs around for years in cfml like this?