File Structure for Google Cloud Functions (Python): Support for Development and Split Independent Files

Jun 5, 2019

Two obvious isues for Python Cloud Functions are


I recommend the following structure

├── app
│   ├── functions
│   │   ├──
│   │   └──
│   ├──'
│   └──
├── keys
│   ├── PROJECT_ID-datastore.json
│   └── PROJECT_ID-firebase-adminsdk.json
├── templates
│   └── hello_world.html
└── requirements.txt

Common/Shared files

app/ store common shared variables and methods used by cloud functions.

import loggingimport sysfrom functools import wrapsfrom flask import abort, jsonify, make_response, render_templatefrom app.settings import PROJECT_IDlog = logging.getLogger(__name__)IS_DEV = Falsedef init(debug):    global IS_DEV    IS_DEV = debug    if debug:        if not log.handlers:            log.setLevel(logging.DEBUG)            formatter = logging.Formatter(fmt="%(asctime)s %(levelname)s %(module)s: %(message)s", datefmt="%H:%M:%S")            handler = logging.StreamHandler(sys.stdout)            handler.setLevel(logging.DEBUG)            handler.setFormatter(formatter)            log.addHandler(handler)# json_abort(status_code, message, details=None):    data = {        'error': {            'code': status_code,            'message': message        }    }    if details:        data['error']['details'] = details    response = jsonify(data)    response.status_code = status_code    abort(response)def html_abort(status_code, message):    response = make_response(render_template('abort.html', message=message, TITLE='Error'), status_code)    # response.status_code = status_code    abort(response)firestore_db = Nonedef init_firestore():    import firebase_admin    from firebase_admin import credentials    from firebase_admin import firestore    global firestore_db    if firestore_db:        return firestore_db    if not IS_DEV:        cred = credentials.ApplicationDefault()    else:        cred = credentials.Certificate(f"keys/{PROJECT_ID}-firebase-adminsdk.json")    default_app = firebase_admin.initialize_app(cred, {      'projectId': {PROJECT_ID}    })    firestore_db = firestore.client()    return firestore_dbdatastore_db = Nonedef init_datastore():    from import datastore    global datastore_db    if IS_DEV:        datastore_db = datastore.Client.from_service_account_json(f"keys/{PROJECT_ID}-datastore.json")    else:        datastore_db = datastore.Client()    return datastore_dbdef firebase_auth_required(f):    @wraps(f)    def wrapper(request):        authorization = request.headers.get('Authorization')        id_token = None        if authorization and authorization.startswith('Bearer '):            id_token = authorization.split('Bearer ')[1]        else:            json_abort(401, message="Invalid authorization")        try:            decoded_token = auth.verify_id_token(id_token)        except Exception as e: # ValueError or auth.AuthError            json_abort(401, message="Invalid authorization")        return f(request, decoded_token)    return wrapper

NOTE: For datastore and firetore, I am connecting to production server for local development testing. I haven't tried datastore emulator and firestore emulator.

Example of app/


You could have other shared files like app/, app/, etc.

Cloud Functions

Each cloud functions is created as individual file in app/functions directory.

Example of app/functions/

from flask import render_templatedef test_hello_world(request):    return render_template('test_hello_world.html')


<!doctype html><html lang="en">  <head>    <meta charset="utf-8">    <title>Test Hello World</title>  </head>  <body>    <h1>Test Hello World</h1>  </body></html>



from app.functions.test_hello_world import *# from app.functions.test_logging import *


gcloud functions deploy test_hello_world --runtime python37 --trigger-http --project PROJECT_ID

Local Development Testing


import loggingimport sysimport appIS_DEV = Falseif __name__ == '__main__':    IS_DEV = Trueapp.init(debug=IS_DEV)from app.functions.test_hello_world import *from app.functions.test_logging import *if IS_DEV:    from flask import Flask, request    app = Flask(__name__)    '''    @app.route('/', methods=['POST', 'GET'])    def test():        return test_message(request)    '''    functions = [        'test_hello_world',        'test_logging'        ]    # app.add_url_rule(f'/test_message', 'test_message', test_message, methods=['POST', 'GET'], defaults={'request': request})    for function in functions:        app.add_url_rule(f'/{function}', function, locals()[function], methods=['POST', 'GET'], defaults={'request': request})'', port=8088, debug=True)

Start development server


NOTE: Make sure you are using Python 3.7.



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