Blazon

A script and systemd unit template for setting up OnFailure= notifications on any systemd service unit. It currently supports the following notification channels:

Desktop via notify-send and D-Bus
Slack via Incoming Webhook

Pagerduty support is being added "soon"™️

Install the systemd unit template

Automatically:

Run sudo ./install

Manually:

sudo cp units/* /etc/systemd/system/
cp bin/blazon /usr/local/bin
Run systemctl daemon-reload

Add Blazon to specific systemd units ✨✨

Add an override for your service on the blazon@.service systemd template. In this example we are adding in notifications to Hashicorp Vault. Run systemctl edit blazon@vault.service and add these overrides to the new unit.

[Service]
Environment=BLAZON_NOTIFY_DESKTOP=true
Environment=BLAZON_NOTIFY_SLACK=true
Environment=BLAZON_NOTIFY_PAGERDUTY=true
Environment=BLAZON_SLACK_WEBHOOK_URL=https://hooks.slack.com/services/AAAAAAAAAAA/BBBBBBBBBBB/CCCCCCCCCCCCCCCCCCCCCC

Next you will add the below to the vault.service unit with systemctl edit vault.service

[Unit]
OnFailure=blazon@%N.service

Once that is done, reload systemd systemctl daemon-reload and tada, you now have notifications on your vault.service unit!!🎉

Add to all systemd units 📣📣

⚠️ Warning: This could be noisy if you have a lot of services. Use at your own risk!

Add OnFailure=blazon@%N.service to /etc/systemd/system/service.d/10-blazon.conf:

tee /etc/systemd/system/service.d/10-blazon.conf <<EOF
[Unit]
OnFailure=blazon@%N.service
EOF

Prevent ensures that if a blazon@.service instance fails it will not trigger an instance named blazon@blazon.service:

mkdir /etc/systemd/system/blazon@.service.d/
ln -s /dev/null /etc/systemd/system/blazon@.service.d/10-blazon.conf

and reload systemd systemctl daemon-reload. Now all services will have the OnFailure=blazon@%N.service dependency.

Testing notifications 🧪🧪

Install the blazon-failure-test.service unit:

install -m 0644 units/blazon-failure-test.service /etc/systemd/system

Configure blazon to notify when it fails with systemctl edit blazon@blazon-failure-test.service and add:

[Service]
Environment=BLAZON_NOTIFY_DESKTOP=true
Environment=BLAZON_NOTIFY_SLACK=true
Environment=BLAZON_NOTIFY_PAGERDUTY=true
Environment=BLAZON_SLACK_WEBHOOK_URL=https://hooks.slack.com/services/AAAAAAAAAAA/BBBBBBBBBBB/CCCCCCCCCCCCCCCCCCCCCC

Reload systemd with systemctl daemon-reload and start the blazon-failure-test.service with systemctl start blazon-failure-test.service. This unit will fail on start and notify with Blazon. When you are done testing your notifications, you can run the following to remove it:

systemctl stop blazon-failure-test.service
rm -f /etc/systemd/system/blazon-failure-test.service
rm -rf /etc/systemd/system/blazon@blazon-failure-test.service.d/
systemctl daemon-reload

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.