telegram.md

Publishing updates to a Telegram channel

Posting diffs and the graph to a Telegram channel requires a few steps, and though they're not super complicated, I didn't find them described succinctly anywhere.

Create a new Telegram bot and get the authorization token

This is documented in the BotFather documentation.

• Start a chat with the BotFather account
• Create a new bot by sending /newbot as a message
• Follow the prompts to add name and username for the bot
• Copy the token from the response and stick it, for example, into a GitHub Actions secret
• Use /mybots to add a profile picture for bonus points

Create a new Telegram channel and get its ID

• Create a new Telegram channel, via mobile app, desktop app, or web client; making it private is probably a reasonable idea

• Add your new bot via "Add members"

• Post a message in the channel; the getUpdates method only shows updates from the last 24 hours

• Make a GET request to https://api.telegram.org/bot<token>/getUpdates; the response looks something like this:

  {
    "ok": true,
    "result": [
      {
        "update_id": 808628153,
        "channel_post": {
          "message_id": 15,
          "sender_chat": {
            "id": -1001310120257,
            "title": "My new channel",
            "type": "channel"
          },
          "chat": {
            "id": -1001310120257,
            "title": "My new channel",
            "type": "channel"
          },
          "date": 1623113410,
          "text": "The message"
        }
      }
    ]
  }

  where the ID we're looking for is -1001310120257 (including the dash!)

  For a more general case with potentially multiple channels, we can automate the extraction using jq, as long as we know the channel title:

  curl --silent "https://api.telegram.org/bot$(< token)/getUpdates" \
      | jq --arg title 'My new channel' '
          .result |
          map(
              select(.channel_post.chat.title == $title)
          )[0].channel_post.chat.id
      '

  This requires the authorization token to be stored in a file named token in the current directory.

Sending Telegram messages as part of the action

Armed with the token and the channel ID, we can send messages to our new channel. The Slack analyzer action uses appleboy/telegram-action for this (transparently).

All that has to be done is setting the optional telegram-to and telegram-token inputs; assuming they are stored as secrets TELEGRAM_TO and TELEGRAM_TOKEN:

- name: Update Slack workspace analysis
  uses: bewuethr/slack-analyzer@v0
  with:
    name: Foo Corp
    slack-bot-token: ${{ secrets.BOT_TOKEN }}
    slack-user-token: ${{ secrets.USER_TOKEN }}
    telegram-to: ${{ secrets.TELEGRAM_TO }}
    telegram-token: ${{ secrets.TELEGRAM_TOKEN }}

And that's it! Happy telegramming!