This plugin provides a handler to send notifications to a Telegram chat.

• bin/handler-telegram.rb

After installation, you have to set up a pipe type handler, like so:

{
  "handlers": {
    "telegram": {
      "type": "pipe",
      "command": "handler-telegram.rb",
      "filter": "occurrences"
    }
  }
}

Note: You need the filter key in there if you use the occurrences and/or the refresh attributes in your check definitions.

This gem also expects a JSON configuration file with the following contents:

{
  "telegram": {
    "bot_token": "YOUR_BOT_TOKEN",
    "chat_id": -123123,
    "error_file_location": "/tmp/telegram_handler_error"
  }
}

• bot_token: your bot's token, as provided by @BotFather.
• chat_id: the chat to which the error message is to be sent. The bot must be a member of this channel or group. You can get the chat_id by adding the bot to the corresponding group, sending a message like /fakecmd @your-bot-username, and then accessing https://api.telegram.org/bot<TOKEN>/getUpdates.
• error_file_location (optional): in case there is a failure sending the message to Telegram (ie. connectivity issues), the exception mesage will be written to a file in this location. You can then monitor this location to detect any errors with the Telegram handler.
• message_template (optional): An ERB template to use to format messages instead of the default. Supports the following variables:
  • action_name
  • action_icon
  • client_name
  • check_name
  • status
  • status_icon
  • output
• message_template_file (optional): A file to read an ERB template from to format messages. Supports the same variables as message_template.

You can then set up your checks to use the handler like this:

{
  "checks": {
    "sensu-website": {
      "command": "check-http.rb -u https://sensuapp.org",
      "subscribers": ["production"],
      "interval": 60,
      "handler": "telegram"
    }
  }
}

For more information about configuring checks, see the Sensu documentation.

By default, the handler assumes that the config parameters are specified in the telegram top-level key of the JSON, as shown above. You also have the option to make the handler fetch the config from a different key. To do this, pass the -j option to the handler with the name of the desired key You can define multiple handlers, and each handler can send notifications to a different chat and from a different bot. You could, for example, have critical and non-critical Telegram groups, and send the notifications to one or the other depending on the check. For example:

{
  "handlers": {
    "critical_telegram": {
      "type": "pipe",
      "command": "handler-telegram.rb -j critical_telegram_options"
    },
    "non_critical_telegram": {
      "type": "pipe",
      "command": "handler-telegram.rb -j non_critical_telegram_options"
    }
  }
}

This example will fetch the options from a JSON like this:

{
  "telegram": {
    "bot_token": "YOUR_BOT_TOKEN"
  },
  "critical_telegram_options": {
    "chat_id": -123123
  },
  "non_critical_telegram_options": {
    "chat_id": -456456
  }
}

As you can see, you can specify the default config in the telegram key, and the rest of the config in their own custom keys.

You can also directly add the configuration parameters to the event data using a mutator. For example:

#!/usr/bin/env ruby
require 'rubygems'
require 'json'
event = JSON.parse(STDIN.read, :symbolize_names => true)
event.merge!(chat_id: -456456)
puts JSON.dump(event)

The handler will load the config as follows (from least to most priority):

• Default telegram key
• Custom config keys
• Event data

Installation and Setup