Python Azure function to send telegram messages

Question

I have an Azure Function in python that sends a telegram message with a Time Trigger. It works like a charm in my local environment (using azure and azurite emulators in VS Code). I use the telethon client with an async function declaration. Here is my code:

import asyncio
from telethon import TelegramClient
from telethon.tl.types import InputPeerUser
import azure.functions as func

api_id = '2xxxxxxx'
api_hash = 'xxxxxxxxxxxxxxxxxx6yyyyyyy'
token = '6664444-knfdkjnxxxxx-xxxxx'

async def telegram_main(client,receiver,message,token):
                await client.start(bot_token=token)
                await client.connect()
                await client.send_message(receiver, message)
                await client.disconnect()
                
async def main(mytimer: func.TimerRequest) -> None:
    utc_timestamp = datetime.datetime.utcnow().replace(
        tzinfo=datetime.timezone.utc).isoformat()

    if mytimer.past_due:
        logging.info('The timer is past due!')

    logging.info('Python timer trigger function ran at %s', utc_timestamp)

    message = "Hello, this is a test message from Azure Function"

    receiver = InputPeerUser(1111111, 0)
    client = await TelegramClient('bot', api_id, api_hash).start(bot_token=token, max_attempts=10)
    print('client declared')
    
    try:
        print('trying to send telegram message')
        loop = asyncio.get_event_loop()
        task = loop.create_task(telegram_main(client,receiver, message, token))
        await task
        print('Telegram message sent')
    except RuntimeError as e:
        print(e)

When I deploy the function in a Function App, I get the following error message:

Exception while executing function: Functions.Send_TLGRM_MSG <--- Result: 
Failure Exception:
    OperationalError: attempt to write a readonly database 

Stack:

 File "/azure-functions-host/workers/python/3.9/LINUX/X64/azure_functions_worker/dispatcher.py", line 402, in _handle__invocation_request call_result = await self._run_async_func( 
 File "/azure-functions-host/workers/python/3.9/LINUX/X64/azure_functions_worker/dispatcher.py", line 654,
   in _run_async_func return await ExtensionManager.get_async_invocation_wrapper(
 File "/azure-functions-host/workers/python/3.9/LINUX/X64/azure_functions_worker/extension.py", line 147,
   in get_async_invocation_wrapper result = await function(**args)   
 File "/home/site/wwwroot/DB_Scan_TLGRM/__init__.py", line 281,
   in main client = await TelegramClient('bot', api_id, api_hash).start(bot_token=token, max_attempts=10)
 File "/home/site/wwwroot/.python_packages/lib/site-packages/telethon/client/auth.py", line 135,
   in _start await self.connect()
 File "/home/site/wwwroot/.python_packages/lib/site-packages/telethon/client/telegrambaseclient.py", line 549,
   in connect self.session.auth_key = self._sender.auth_key
 File "/home/site/wwwroot/.python_packages/lib/site-packages/telethon/sessions/sqlite.py", line 180,
   in auth_key self._update_session_table()
 File "/home/site/wwwroot/.python_packages/lib/site-packages/telethon/sessions/sqlite.py", line 194,
   in _update_session_table c.execute('delete from sessions')

I declare an async function with my telegram workflow. Then I call that function as a task inside Azure's own event loop (which is a requisite in this case).

As mentioned, this works well in the emulator. I know that telegram bots are possible in Azure functions. This seems to be a problem with authentication, but I've looked everywhere and can't solve it. Any suggestions are welcome.

Answer 1

Python Azure function to send telegram messages

I have reproduced in my environment and below are my expected results:

You don't need client to send, Alternatively you can use below simple code:

Here I created a http trigger, you can use the code and integrate it into Timer Trigger:

__init__.py:

import logging
import requests
import azure.functions as func


def main(req: func.HttpRequest) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')
    rith_bot_token = '662538:AAF4WslGnotZN5Fc'
    rith_chat_id = '-1002124' 
    rith_message = 'Hello Rithwik'

    url = f'https://api.telegram.org/bot{rith_bot_token}/sendMessage'
    data = {'chat_id': rith_chat_id, 'text': rith_message}
    response = requests.post(url, data=data)
    print(response)
    
    return func.HttpResponse(
             "Hello Bot sent the message check it in Telegram",
             status_code=200
        )

requirements.txt:

azure-functions
requests

local.settings.json:

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "connec",
    "FUNCTIONS_WORKER_RUNTIME": "python"
  }
}

Then deployed to Azure.

Output:

Response from Chat bot :