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diff --git a/doc/guix.texi b/doc/guix.texi index 0bb68bb477..7516d75b8d 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -204,6 +204,7 @@ System Configuration Services * Base Services:: Essential system services. +* Scheduled Job Execution:: The mcron service. * Networking Services:: Network setup, SSH daemon, etc. * X Window:: Graphical display. * Desktop Services:: D-Bus and desktop services. @@ -7185,6 +7186,7 @@ declaration. @menu * Base Services:: Essential system services. +* Scheduled Job Execution:: The mcron service. * Networking Services:: Network setup, SSH daemon, etc. * X Window:: Graphical display. * Desktop Services:: D-Bus and desktop services. @@ -7463,6 +7465,82 @@ archive}). If that is not the case, the service will fail to start. @end deffn +@node Scheduled Job Execution +@subsubsection Scheduled Job Execution + +@cindex cron +@cindex scheduling jobs +The @code{(gnu services mcron)} module provides an interface to +GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,, +mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional +Unix @command{cron} daemon; the main difference is that it is +implemented in Guile Scheme, which provides a lot of flexibility when +specifying the scheduling of jobs and their actions. + +For example, to define an operating system that runs the +@command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files}) +and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily: + +@lisp +(use-modules (guix) (gnu) (gnu services mcron)) + +(define updatedb-job + ;; Run 'updatedb' at 3 AM every day. + #~(job '(next-hour '(3)) + "updatedb --prunepaths='/tmp /var/tmp /gnu/store'")) + +(define garbage-collector-job + ;; Collect garbage 5 minutes after midnight every day. + #~(job "5 0 * * *" ;Vixie cron syntax + "guix gc -F 1G")) + +(operating-system + ;; @dots{} + (services (cons (mcron-service (list garbage-collector-job + updatedb-job)) + %base-services))) +@end lisp + +@xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron}, +for more information on mcron job specifications. Below is the +reference of the mcron service. + +@deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}] +Return an mcron service running @var{mcron} that schedules @var{jobs}, a +list of gexps denoting mcron job specifications. + +This is a shorthand for: +@example + (service mcron-service-type + (mcron-configuration (mcron mcron) (jobs jobs))) +@end example +@end deffn + +@defvr {Scheme Variable} mcron-service-type +This is the type of the @code{mcron} service, whose value is an +@code{mcron-configuration} object. + +This service type can be the target of a service extension that provides +it additional job specifications (@pxref{Service Composition}). In +other words, it is possible to define services that provide addition +mcron jobs to run. +@end defvr + +@deftp {Data Type} mcron-configuration +Data type representing the configuration of mcron. + +@table @asis +@item @code{mcron} (default: @var{mcron2}) +The mcron package to use. + +@item @code{jobs} +This is a list of gexps (@pxref{G-Expressions}), where each gexp +corresponds to an mcron job specification (@pxref{Syntax, mcron job +specifications,, mcron, GNU@tie{}mcron}). +@end table +@end deftp + + @node Networking Services @subsubsection Networking Services |