At run time, shepherd maintains a service registry that
maps service names to service records. Service dependencies are
expressed as a list of names passed as #:requirement to the
service procedure (see Defining Services); these names are
looked up in the registry. Likewise, when running herd start
sshd or similar commands (see Jump Start), the service name is
looked up in the registry.
Consequently, every service must be appear in the registry before it can
be used. A typical configuration file thus includes a call to the
register-services procedure (see Service Examples). The
following procedures let you interact with the registry.
Register services so that they can be looked up by name, for instance when resolving dependencies.
Each name uniquely identifies one service. If a service with a given name has already been registered, arrange to have it replaced when it is next stopped. If it is currently stopped, replace it immediately.
Remove all of services from the registry, stopping them if they are not already stopped.
Return the service that provides name, #f if there is none.
Call proc, a procedure taking one argument, once for each registered service.
Return the running service that provides name, or false if none.