notify-by-telegram

Send Nagios notifications to a Telegram Messenger channel.

Telegram bot

This tutorial explains how to create a Telegram bot. You'll need the chat_id and auth_key for the next section.

Installation

This guide has been written for Debian. Some commands might slightly change depending on your distribution.

Clone the repository:

git clone https://git.riou.xyz/jriou/notify-by-telegram.git /opt/notify-by-telegram

Install dependencies using pip:

pip install -r requirements.txt

Or via the package manager:

sudo apt install python3-jinja2 python3-requests python3-jsonschema

Configuration

Copy and update the configuration file example:

cp -p config.example.json telegram.json
vim telegram.json
sudo mv telegram.json /etc/nagios4/telegram.json
sudo chown root:nagios /etc/nagios4/telegram.json
sudo chmod 640 /etc/nagios4/telegram.json

Ensure Nagios reads the configuration file:

echo "cfg_file=/opt/notify-by-telegram/nagios.cfg" >> /etc/nagios4/nagios.cfg

Then reload service:

systemctl reload nagios4

Configuration file

Format used is JSON with the following keys:

• chat_id: where to send message on Telegram
• auth_key: key used to authenticate on Telegram
• host_template (optional): path to Markdown template file used for sending host notifications
• service_template (optional): path to Markdown template file used for sending service notifications

Logging

Errors logs can be set with the --logfile argument.

Example:

tail -f /var/log/nagios4/telegram.log

Log level can be raised using --verbose or even more with --debug arguments.

Message format

notify-by-telegram script uses the MarkdownV2 format to generate Telegram messages.

Jinja is used for templating (eg. replace {{host_name}} placeholders by the value submitted by Nagios).

Default host and service templates can be found in the templates directory.

They can be overriden in the configuration file:

{
  "host_template": "/etc/nagios4/host.md.j2",
  "service_template": "/etc/nagios4/service.md.j2"
}

Both options are optional.

Host variables

Variables replaced in the host template:

• notification_type (= $NOTIFICATIONTYPE$)
• host_name (= $HOSTNAME$)
• host_state (= $HOSTSTATE$)
• host_address (= $HOSTADDRESS$)
• host_output (= $HOSTOUTPUT$)
• long_date_time (= $LONGDATETIME$)

Service variables

Variables replaced in the service template:

• notification_type (= $NOTIFICATIONTYPE$)
• service_desc (= $SERVICEDESC$)
• host_alias (= $HOSTALIAS$)
• host_address (= $HOSTADDRESS$)
• service_state (= $SERVICESTATE$)
• long_date_time (= $LONGDATETIME$)
• service_output (= $SERVICEOUTPUT$)

How to contribute

Contributions are welcomed! Feel free to update the code and create a pull-request.

Be sure to lint the code before:

docker build -t pre-commit .
docker run -it -v $(pwd):/mnt/ --rm pre-commit bash
# cd /mnt/
# pre-commit run --all-files
# exit