5.3 Transient Service Maker ¶

The transient service maker lets you run commands in the background, and it does so by wrapping those commands in transient services (see Defining Services). It is similar to the systemd-run command, which you might have encountered before.

A simple configuration file that uses this service looks like this:

(use-modules (shepherd service transient))

(register-services (list (transient-service)))

This creates a service called transient that has a spawn action, which you can use like this:

# Run 'make' from the current directory.
herd spawn transient -d "$PWD" -- make -j4

# Run 'rsync' from the home directory, inheriting
# the 'SSH_AUTH_SOCK' environment variable.
herd spawn transient \
  --log-file=backup.log \
  -E SSH_AUTH_SOCK=$SSH_AUTH_SOCK -- \
  rsync -e ssh -vur . backup.example.org:

Each of these herd spawn transient commands creates a new transient service. Like any other service, they can be inspected and stopped. Running herd stop transient stops all the currently running transients.

The command runs from the directory specified by default-service-directory or from that specified by the --working-directory option of herd; it starts with the environment variables in default-environment-variables, augmented with HOME when running as a different user, with the addition of variables passed with --environment-variable. See Invoking herd, for more info on influential command-line options.

Procedure: transient-service [provision] [#:requirement ’()] ¶

Return a service with the given provision and requirement. The service has a spawn action that lets users run commands in the background.