telegram-group2mastodon

telegram-group2mastodon is a Telegram bot to post messages from a Telegram group to Mastodon. It's written in Go and it is relased under the AGPL3+. Since the bot must be able to read all the messages you should use it only on public groups.

Installation

1. Build the bot (for example if version is v0.1.0 and you are on a unix system):

   cd /tmp; GOPATH=/tmp/go go install noa.mornie.org/eriol/telegram-group2mastodon@v0.1.0
   

   You will find the binary at /tmp/go/bin/telegram-group2mastodon. You don't need to set GOPATH if you already have it set and you are fine having the bot installed there.

2. Create your bot using Telegram @BotFather.

3. The bot uses environment variables as configuration, you have to export the following (except variables with a default) before starting it:

   Variable	Meaning	Default
   MASTODON_ACCESS_TOKEN	Mastodon access token	N/A
   MASTODON_SERVER_ADDRESS	Mastodon server address	N/A
   MASTODON_TOOT_FOOTER	Footer of each toot	""
   MASTODON_TOOT_MAX_CHARACTERS	Toot max lenght	500
   MASTODON_TOOT_VISIBILITY	Default toot visibility	unlisted
   TELEGRAM_BOT_TOKEN	Telegram bot token	N/A
   TELEGRAM_CHAT_ID	Telegram alolowed chat id	N/A
   TELEGRAM_DEBUG	Debug messages from Telegram	False

   MASTODON_TOOT_VISIBILITY allowed values are: direct, private, public and unlisted. MASTODON_TOOT_FOOTER default is an empty string that disable the footer feature, no character are automatically added so you may want to add a space before your footer (or a new line). To get MASTODON_ACCESS_TOKEN see next point.

4. To get MASTODON_ACCESS_TOKEN use the subcommand authenticate:

   telegram-group2mastodon authenticate <https://your.instance>
   

   and follow the istructions.

5. Ensure that the telegram bot can access all the messages disabling privacy mode: https://core.telegram.org/bots/features#privacy-mode

6. Launch the bot:

   telegram-group2mastodon run
   

Deploy using Docker/Podman

Images are automatically built after each push on quay.io, here the list of available tags: https://quay.io/repository/eriol/telegram-group2mastodon?tab=tags

docker

Suppose you want to use the latest tag.

docker run \
    --env MASTODON_ACCESS_TOKEN=$MASTODON_ACCESS_TOKEN \
    --env MASTODON_SERVER_ADDRESS=$MASTODON_SERVER_ADDRESS \
    --env TELEGRAM_BOT_TOKEN=$TELEGRAM_BOT_TOKEN \
    --env TELEGRAM_CHAT_ID=$TELEGRAM_CHAT_ID \
    quay.io/eriol/telegram-group2mastodon:latest

podman

Suppose you want to use the latest tag.

podman run \
    --env MASTODON_ACCESS_TOKEN=$MASTODON_ACCESS_TOKEN \
    --env MASTODON_SERVER_ADDRESS=$MASTODON_SERVER_ADDRESS \
    --env TELEGRAM_BOT_TOKEN=$TELEGRAM_BOT_TOKEN \
    --env TELEGRAM_CHAT_ID=$TELEGRAM_CHAT_ID \
    quay.io/eriol/telegram-group2mastodon:latest

docker-compose

---
version: "3.9"

services:
  bot:
    image: quay.io/eriol/telegram-group2mastodon:latest
    environment:
      - MASTODON_ACCESS_TOKEN=${MASTODON_ACCESS_TOKEN}
      - MASTODON_SERVER_ADDRESS=${MASTODON_SERVER_ADDRESS}
      - TELEGRAM_BOT_TOKEN=${TELEGRAM_BOT_TOKEN}
      - TELEGRAM_CHAT_ID=${TELEGRAM_CHAT_ID}

Deploy on metal

You have to build the bot and use a init system of your choice to handle it.

systemd

Suppose you put the bot in /srv/tg2m/telegram-group2mastodon an example unit file using an user tg2mbot could be:

[Unit]
Description=a Telegram bot to post messages from a Telegram group to Mastodon
After=network-online.target
Wants=network-online.target

[Service]
ExecStart=/srv/tg2m/telegram-group2mastodon run
User=tg2mbot
Group=tg2mbot
Restart=on-failure
Environment=MASTODON_ACCESS_TOKEN=<MASTODON_ACCESS_TOKEN>
Environment=MASTODON_SERVER_ADDRESS=<MASTODON_SERVER_ADDRESS>
Environment=TELEGRAM_BOT_TOKEN=<TELEGRAM_BOT_TOKEN>
Environment=TELEGRAM_CHAT_ID=<TELEGRAM_CHAT_ID>

[Install]
WantedBy=multi-user.target

where you have to put the real values for <MASTODON_ACCESS_TOKEN>, <MASTODON_SERVER_ADDRESS>, <TELEGRAM_BOT_TOKEN> and <TELEGRAM_CHAT_ID>.