My question is very similar to this one: How to use telegram webhook on google cloud functions?
I have the same identical problem but I want to deploy it on Google App Engine. I have set up my bot using the python-telegram-bot library (code below) and actually it is hosted on Heroku and works well.
import os
TOKEN = "TOKEN"
PORT = int(os.environ.get('PORT', '8443'))
updater = Updater(TOKEN)
# add example handler
def start(update, context):
context.bot.send_message(chat_id=update.message.chat_id, text="Hello, I am dice bot and I will roll some tasty dice for you.")
start_handler = CommandHandler('start', start)
dispatcher.add_handler(start_handler)
# start webhook polling
updater.start_webhook(listen="0.0.0.0",
port=PORT,
url_path=TOKEN)
updater.bot.set_webhook("https://<appname>.appspot.com/" + TOKEN)
updater.idle()
My Bot is not responding and if I try to browse my app I get 502 ERORR Bad Gateway. Of course I deleted the previous webhook on my Bot.