FurCast Telegram Bot

• Gates entry to the main FurCast group, to reduce bot activity
• Information and utility functions like /next [show] [tz]

Runs both as a poll bot and a free Google Cloud Function. The poll bot handles most things, especially those requiring state like /next pin. The GCF copy handles external events like Now Playing announcements.

Commands

next - See next scheduled show, e.g. "/next fnt" or "/next fc Europe/London"
topic - Request chat topic, e.g. "/topic Not My Cup Of Legs"
report - Get admin attention. Reply to a message with e.g. "/report Spambot!"

Other commands

Don't tell BotFather.

chatinfo - List the chat ID
newlink [slug] [link [link...]] - (Admin group) Revoke invite link(s)
next [slug] pin - Pin a continuously updated countdown message
start - (PM) Print some help & suggest /join. Prompted by TG client.
join - (PM) Request a group invite
stopic - Silently set the topic (delete command message)
version - Print the source link and GCF version if available

How to use

• Generate a random alphanumeric token to be used as an API key for the bot, eg:

  APIKEY=$(tr -cd '[:alnum:]'</dev/urandom|fold -w32|head -n1)

• Create a private group (or make your group private). If you don't want the bot to have admin, generate an invite link for $JOIN_LINK below

• Create a bot, eg @furcastbot, to run this, and save the bot token for $TELEGRAM_TOKEN below

• Create a channel with the @ you want, eg. @furcastfm, and write a message instructing users to talk to the bot for entry to the group.

• If using poll bot, assuming linux account name is bots:

  • Copy config.toml.example to config.toml and edit
  • virtualenv -p python3 venv
  • . venv/bin/activate
  • pip install --upgrade .
  • deactivate
  • venv/bin/furcastbot to verify functionality
  • For systemd:
    • sudo loginctl enable-linger bots
    • ln -s ../../../furcast-tg-bot/contrib/furcastbot.service ~/.config/systemd/user/furcastbot.service
    • systemctl --user daemon-reload
    • systemctl --user enable --now furcastbot
  • For OpenBSD (and maybe other sysv-style init systems, we haven't checked):
    • doas cp ../../../furcast-tg-bot/contrib/openbsd.rc /etc/rc.d/furcast_bot
    • doas chmod +x /etc/rc.d/furcast_bot
    • doas rcctl start furcast_bot
    • doas rcctl enable furcast_bot
    • (If you want to run multiple copies of the bot, we recommend copying the rc script and fiddling with the variables, rather than symlinking and using rcctl set service_name flags, since the config file is not read from the flags.)

• For the GCP part:

  • Set up a new GCP project
  • Enable Cloud Functions for the project
  • EITHER create a new function and manually configure it and upload the source, or continue:
  • Set up the Google Cloud SDK's gcloud tool with a configuration named 'xbn':

  gcloud config configurations create xbn
  gcloud auth login
  gcloud config set project xana-broadcasting

  • Deploy to GCF with the Google Cloud SDK (Repeat after code/config updates)

  gcloud functions deploy furcast-tg-bot --trigger-http --entry-point webhook \
    --memory 128M --timeout 5s --configuration xbn --set-env-vars "JOIN_LINK=error" \
    --runtime python311 --docker-registry=artifact-registry --set-build-env-vars=GOOGLE_FUNCTION_SOURCE=main.py

  • From the output, get httpsTrigger.url, and set the webhook in the telegram bot:

  curl "https://api.telegram.org/bot$TELEGRAM_TOKEN/setWebhook?url=$TRIGGER_URL&apikey=$APIKEY"

Helpful stuff:

# Re-deploy with the same settings,
gcloud functions deploy furcast-tg-bot --configuration xbn