How can I use flask routing on google cloud functions? - flask

Question

I want to make a simple serverless backend, so I'm trying to use google cloud functions with flask routing.
I'm trying to test a simple code, but it's not working. The following source always returns 404 errors.
from flask import Flask, make_response
class Services:
pass
def create_app(test_config = None):
app = Flask(__name__)
services = Services
create_endpoints(app, services)
return app
def create_endpoints(app, services):
#app.route("/test", methods=['GET'])
def test():
return make_response('Test worked!', 200)
function URL : ######.cloudfunctions.net/test1
I tried "######.cloudfunctions.net/test1" and "######.cloudfunctions.net/test1/test", but it always returns 404 error.
can I use flask routing ?

Answer 1

I think that it is a not fancy way to add a router to a cloud function, but it works.
I used the property "path" of the object "request"( this is a flask.request object) to read the path after the domain in the requested URL
from flask import abort
def coolrouter(request):
path = (request.path)
if (path == "/test"):
return "test page"
elif (path == "/home" or path =="/"):
return "ḧome page"
else:
abort (404)
keep in mind that cloud functions are designed to be a one shot services, that means that is not possible to save session variables or other things since this is service is ephemeral.
If you want upload a complete site I recommend you to use App Engine, which is a Fully managed serverless application platform.

Answer 2

Google now has api gateway which would allow you to have a single endpoint to handle all of your routes. See goblet as an easy way to manage and deploy your api to api gateway

Answer 3

I agree with all the answers given here, but I want to elaborate a bit from my experience. Since Cloud Functions are designed for single-purpose use only. It can process HTTP requests and events from pubsub, storage etc. When using API gateway or Cloud Endpoints in front of your Cloud Functions, you can offload authentication and routing, so your code has only one responsibility.
However, the downside that you will never get rid of the cold-start problem when using Cloud Functions as an API. Serving requests can sometimes last up to 2-10 seconds or more, depending on the size of your code and programming language. So you are probably better of with Google App Engine or something that you can reserve to be "always there".
I am currently experimenting with the Cloud Function + API Gateway setup. I am routing GET, POST and DELETE methods for one object to the same cloud function. So I am basically trying to let it be single-purpose in the way that one function only handles requests for only one object. This could easily be accomplished with a switch case on the method used, so no routing is needed. A schematic example:
Cloud function one:
Path: /blogs
Methods: GET, POST, DELETE
Purpose: Handles all actions on blog objects
Cloud function two:
Path: /posts
Methods: GET, POST, DELETE
Purpose: Handles all actions on post objects

Answer 4

According to the official documentation:
Cloud Functions is a serverless execution environment for building and
connecting cloud services. With Cloud Functions you write simple,
single-purpose functions that are attached to events emitted from your
cloud infrastructure and services. Your function is triggered when an
event being watched is fired.
Python Quickstart Cloud Functions