Service

A service is defined using a systemd style service file. But finit doesn't support all the different options defined by systemd (about 850). It only supports this tiny subset and ignores the rest:

• requires: A list of units that must be present.
• wants: A list of units that will be started if found.
• before: A list unit this units that will not be started until this unit is started.
• after: A list of units that must be started prior to this unit.
• defaultdependencies: By default all units will by default run after the targets sysinit and basic. Any unit that needs to run before must set this option to no.
• type: Type of service (see below).
• execstart: What will be executed to start this unit.
• pidfile: A path to where the daemon will write it's PID.

There are basically three types of servises:

1. Child: The service will run as a child to finit. The only way for finit to delay until the service is ready is if it uses the systemd notification protocol. Otherwise finit will assume it's immediately ready.
2. Daemon: The service will run independently by forking then it's ready. For finit to be able to keep track of it, a path to a PID file must be provided.
3. Oneshot: The service only executes something to get ready. Nothing remains running.

The types defined by systemd are these:

• simple: This is mapped to child.
• forking: This is the same as daemon.
• oneshot: Same as above.
• dbus: This is like child but notification goes through D-BUS. This is not supported by finit.
• notify: This is child with notification using the systemd protocol.
• notify-reload: This is identical to notify but it also implies that the service could be reloaded using SIGHUP. (Note that there is no forking-reload for some reason.)
• idle: This is mapped to child.
• exec: This is mapped to child.