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Private Telegram Chat Bot

This chapter shows you how to build a simple Telegram bot that will run inside ROFL. Along the way you will meet one of the most powerful ROFL features—how to safely store your bot's Telegram API token inside a built-in ROFL key-store protected by the Trusted Execution Environment and the Oasis blockchain!

Prerequisites​

This guide requires:

  • a working python (>3.9)
  • a working Docker (or Podman),
  • Oasis CLI and
  • at least 120 TEST tokens in your wallet.

Check out the Quickstart Prerequisites section for details.

Init App​

First we init the basic directory structure for the app using the Oasis CLI:

oasis rofl init rofl-tgbot
cd rofl-tgbot

Create App​

Now create an app on Testnet (requires deposit of 100 TEST):

oasis rofl create --network testnet

After successful creation, the CLI will also output the new identifier, for example:

Created ROFL application: rofl1qqn9xndja7e2pnxhttktmecvwzz0yqwxsquqyxdf

Python Telegram Bot​

Use a simple python-telegram-bot wrapper. As a good python citizen create a new folder for your project. Then, set up a python virtual environment and properly install the python-telegram-bot dependency:

python -m venv my_env
source my_env/bin/activate
echo python-telegram-bot > requirements.txt
pip install -r requirements.txt

Create a file called bot.py and paste the following bot logic that greets us back after greeting it with the /hello command:

bot.py
import os
from telegram import Update
from telegram.ext import ApplicationBuilder, CommandHandler, ContextTypes


async def hello(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
    await update.message.reply_text(f'Hello {update.effective_user.first_name}')


app = ApplicationBuilder().token(os.getenv("TOKEN")).build()

app.add_handler(CommandHandler("hello", hello))

app.run_polling()

Next, generate a Telegram API token for our bot. Search for @BotFather in your Telegram app and start a chat with the /newbot command. Then, you'll need to input the name and a username of your bot. Finally, @BotFather will provide you a token that resembles something like 0123456789:AAGax-vgGmQsRiwf4WIQI4xq8MMf4WaQI5x.

As you may have noticed our bot above will read its Telegram API token from the TOKEN environment variable. Since we'll use this variable throughout the tutorial, let's export it for our session and then we can run our bot:

export TOKEN="0123456789:AAGax-vgGmQsRiwf4WIQI4xq8MMf4WaQI5x"
python bot.py

The bot should be up and running now, so you can search for its username in your Telegram app and send it a /hello message:

Python Telegram Bot

Containerize the Bot​

Create Dockerfile which copies over the python script to an alpine linux with installed python:

Dockerfile
FROM python:alpine3.17

WORKDIR /bot
COPY ./bot.py ./requirements.txt /bot
RUN pip install -r requirements.txt

CMD ["python", "bot.py"]

Then add compose.yaml which simply spins up the container image from above:

compose.yaml
services:
  python-telegram-bot:
    build: .
    image: docker.io/YOUR_USERNAME/rofl-tgbot
    platform: linux/amd64
    environment:
    - TOKEN=${TOKEN}

Build ROFL Bundle​

To build a ROFL bundle invoke the following:

oasis rofl build

Secrets​

Do you recall the TOKEN environment variable we exported above? Now, we will encrypt it and safely store it on-chain, so that it will be fed to our bot container once it's started on one of the TEE provider's nodes:

echo -n "$TOKEN" | oasis rofl secret set TOKEN -

To submit this secret and the signatures (enclave IDs) of our .orc bundle components on-chain run:

oasis rofl update

Deploy​

Finally, we deploy our ROFL bundle to a Testnet node instance offered by one of the ROFL providers:

oasis rofl deploy

Congratulations, you have just deployed your first app in ROFL! 🎉

Go ahead and test it by sending the /hello message in the Telegram app. You can also check out your app on the Oasis Explorer:

Oasis Explorer - ROFL

ROFL Telegram Bot

You can fetch a finished project of this tutorial from GitHub here.