If you ever wanted to get notified when certain things happen but didn’t find a lightweight solution – here comes captain Telegram.

Using a simple Telegram bot, it’s possible to send notifications to your mobile phone or browser. All the notifier node needs is curl installed.

Registering a bot

First of all, a Telegram bot has to be registered in order to send messages later on. Follow these steps to get started:

• Using your Telegram client, send a message to @BotFather with the command /newbot and follow the instructions.
• Note the bot token you receive after successfully registering the bot.
• Message your bot with a simple message like /start or /test.

Now use

curl -i -X GET https://api.telegram.org/bot<BOT_TOKEN>/getUpdates

to get the chat ID of the chat you created in the previous chat.

Sending messages

Now, you should have to following things:

• Bot API token
• Chat ID of the chat between you and your newly created bot.

To send a message, it’s as simple as using the following command structure

curl -i -X GET "https://api.telegram.org/bot<BOT_TOKEN>/sendMessage?chat_id=<CHAT_ID>&text=hello"

Example 1: Jenkins build notifications

In order to get notified in case a Jenkins build succeeds or fails, you can edit the Jenkinsfile as follows

try {
   // Build steps
}
catch(error) {
   // Send Telegram message: Fail
   error "Exception occurred, aborting"
}
// Send Telegram message: Success

Example 2: Travis notifications

If you use Travis CI to build your projects after pushing to GitHub, notifications can be implemented by editing the .travis.yml file:

after_success:
  - curl -iX GET "https://api.telegram.org/bot$TOKEN/sendMessage?chat_id=$CHATID&text=Build OK" 2>&1 >/dev/null

after_failure:
  - curl -iX GET "https://api.telegram.org/bot$TOKEN/sendMessage?chat_id=$CHATID&text=Build failed" 2>&1 >/dev/null

Two things are important here:

1. Redirect the output to /dev/null in order to prevent the chat ID from being logged into the public build log.
2. Add your secrets ($TOKEN and $CHATID) to the repository specific settings in Travis to populate the used environment variables in a secure manner.