1

I'm trying make a simple telegram bot in Google App Engine.

When I open the console in GAE, and enter the following, the webhook gets set up just fine

curl -F "url=https://example.appspot.com:8443/<token>"  -F "certificate=@certificate.pem" 
      https://api.telegram.org/bot<token>/setWebhook

But when I run this python script in GAE (of course, having deleted the previous webhook), the webhook doesn't get set up. I couldn't figure out what did I do wrong. 

import sys
import os
import time
from flask import Flask, request
import telegram

# CONFIG
TOKEN    = '<token>'
HOST     = 'example.appspot.com' # Same FQDN used when generating SSL Cert
PORT     = 8443
CERT     = "certificate.pem"
CERT_KEY = "key.pem"


bot = telegram.Bot(TOKEN)
app = Flask(__name__)


@app.route('/')
def hello():
    return 'Hello World!'


@app.route('/' + TOKEN, methods=['POST','GET'])
def webhook():
    update = telegram.Update.de_json( request.get_json(force = True), bot )
    chat_id = update.message.chat.id
    bot.sendMessage(chat_id = chat_id, text = 'Hello, there')

    return 'OK'


def setwebhook():
    bot.setWebhook(url = "https://%s:%s/%s" % (HOST, PORT, TOKEN), certificate = open(CERT, 'rb'))


if __name__ == '__main__':
    context = (CERT, CERT_KEY)
    setwebhook()
    time.sleep(5)
    app.run(host = '0.0.0.0', port = PORT, ssl_context = context, debug = True)

The app.yaml file is as follows:

runtime: python27
api_version: 1
threadsafe: yes

- url: .*
  script: main.app

libraries:
- name: webapp2
  version: "2.5.2"
- name: ssl
  version: latest

EDIT: I changed the app.yaml file as follows but I still can't set up a webhook. It now gives me "502 bad gateway nginx" error

runtime: python
env: flex
entrypoint: gunicorn -b :8443 main:app
threadsafe: true

runtime_config:
  python_version: 2
Trafalgar Law
  • 7
  • 5
  • Are getting any error message? Also, please provide the app.yaml file for this service – LundinCast Mar 19 '18 at 20:52
  • "Hello World" is displayed whenever I run that. When I try to run webhook() I get "Bad Request The browser (or proxy) sent a request that this server could not understand". But I think that's because the webhook to telegram simply is not set up (I checked it with getWebhookInfo in the Telegram Bot API). – Trafalgar Law Mar 20 '18 at 04:59
  • Note that the flex env is significantly different than the standard one, you may need to do some reading. Did you do your port forwarding? https://cloud.google.com/appengine/docs/flexible/python/configuring-your-app-with-app-yaml#port_forwarding – Dan Cornilescu Mar 21 '18 at 04:29

1 Answers1

1

Your app.yaml indicates a standard GAE environment, where a Flask application is referenced solely through the app variable and its handlers/routes. The if __name__ == '__main__': section may not even execute. From Creating a request handler for your Flask app:

  1. Add this line to create an instance of the Flask class and assign it to a variable called app:

    appengine/standard/flask/tutorial/main.py

    app = Flask(__name__)

But you're attempting to run it as a standalone script - which only works locally for a flexible GAE environment app. From Hello World code review:

appengine/flexible/hello_world/main.py 

...
if __name__ == '__main__':
    # This is used when running locally. Gunicorn is used to run the
    # application on Google App Engine. See entrypoint in app.yaml.
    app.run(host='127.0.0.1', port=8080, debug=True)

If you do want to run it this way you need to reconfigure you app as a flexible environment one.

Potentially of interest: How to tell if a Google App Engine documentation page applies to the standard or the flexible environment

Dan Cornilescu
  • 39,470
  • 12
  • 57
  • 97
  • So you're saying that a flexible environment is what I need for my python telegram bot? – Trafalgar Law Mar 20 '18 at 08:53
  • I'm not familiar with telegram. It depends on it being able to work in the restricted standard env sandbox: https://cloud.google.com/appengine/docs/standard/python/runtime#Python_The_sandbox. If that's not possible or too difficult then yes, you need the flex one. – Dan Cornilescu Mar 20 '18 at 12:56
  • See also https://cloud.google.com/appengine/docs/the-appengine-environments – Dan Cornilescu Mar 20 '18 at 12:59