Hooks overview

You can run custom scripts at specific points with hooks.

Hooks should be stored in the .kamal/hooks folder. Running kamal init will build that folder and add some sample scripts.

You can change their location by setting hooks_path in the configuration file.

If the script returns a non-zero exit code the command will be aborted.

KAMAL_* environment variables are available to the hooks command for fine-grained audit reporting, e.g. for triggering deployment reports or firing a JSON webhook. These variables include:

• KAMAL_RECORDED_AT — UTC timestamp in ISO 8601 format, e.g. 2023-04-14T17:07:31Z
• KAMAL_PERFORMER — The local user performing the command (from whoami)
• KAMAL_SERVICE — The service name, e.g. app
• KAMAL_SERVICE_VERSION — An abbreviated service and version for use in messages, e.g. app@150b24f
• KAMAL_VERSION — The full version being deployed
• KAMAL_HOSTS — A comma-separated list of the hosts targeted by the command
• KAMAL_COMMAND — The command we are running
• KAMAL_SUBCOMMAND — Optional: The subcommand we are running
• KAMAL_DESTINATION — Optional: Destination, e.g. “staging”
• KAMAL_ROLE — Optional: Role targeted, e.g. “web”

The available hooks are:

• docker-setup
• pre-connect
• pre-build
• pre-deploy
• post-deploy
• pre-traefik-reboot
• post-traefik-reboot

You can pass --skip_hooks to avoid running the hooks.

Note: The hook filename must be the hook name without any extension. For example, the pre-deploy hook should be named “pre-deploy” (without any file extension such as .sh or .rb).