162 lines
6.2 KiB
Scheme
162 lines
6.2 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gnu services mcron)
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#:use-module (gnu services)
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#:use-module (gnu services shepherd)
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#:autoload (gnu packages guile-xyz) (mcron)
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#:use-module (guix deprecation)
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#:use-module (guix records)
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#:use-module (guix gexp)
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#:use-module (srfi srfi-1)
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#:use-module (ice-9 match)
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#:use-module (ice-9 vlist)
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#:export (mcron-configuration
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mcron-configuration?
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mcron-configuration-mcron
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mcron-configuration-jobs
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mcron-service-type
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mcron-service))
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;;; Commentary:
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;;;
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;;; This module implements a service that to run instances of GNU mcron, a
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;;; periodic job execution daemon. Example of a service:
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;;
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;; (service mcron-service-type
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;; (mcron-configuration
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;; (jobs (list #~(job next-second-from
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;; (lambda ()
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;; (call-with-output-file "/dev/console"
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;; (lambda (port)
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;; (display "hello!\n" port)))))))))
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;;;
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;;; Code:
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(define-record-type* <mcron-configuration> mcron-configuration
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make-mcron-configuration
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mcron-configuration?
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(mcron mcron-configuration-mcron ;package
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(default mcron))
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(jobs mcron-configuration-jobs ;list of <mcron-job>
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(default '())))
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(define (job-file job)
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(scheme-file "mcron-job" job))
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(define (shepherd-schedule-action mcron files)
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"Return a Shepherd action that runs MCRON with '--schedule' for the given
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files."
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(shepherd-action
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(name 'schedule)
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(documentation
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"Display jobs that are going to be scheduled.")
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(procedure
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#~(lambda* (_ #:optional (n "5"))
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;; XXX: This is a global side effect.
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(setenv "GUILE_AUTO_COMPILE" "0")
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;; Run 'mcron' in a pipe so we can explicitly redirect its output to
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;; 'current-output-port', which at this stage is bound to the client
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;; connection.
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(let ((pipe (open-pipe* OPEN_READ
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#$(file-append mcron "/bin/mcron")
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(string-append "--schedule=" n)
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#$@files)))
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(let loop ()
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(match (read-line pipe 'concat)
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((? eof-object?)
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(catch 'system-error
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(lambda ()
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(zero? (close-pipe pipe)))
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(lambda args
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;; There's a race with the SIGCHLD handler, which
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;; could call 'waitpid' before 'close-pipe' above does. If
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;; we get ECHILD, that means we lost the race, but that's
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;; fine.
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(or (= ECHILD (system-error-errno args))
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(apply throw args)))))
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(line
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(display line)
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(loop)))))))))
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(define mcron-shepherd-services
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(match-lambda
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(($ <mcron-configuration> mcron ()) ;nothing to do!
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'())
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(($ <mcron-configuration> mcron jobs)
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(let ((files (map job-file jobs)))
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(list (shepherd-service
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(provision '(mcron))
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(requirement '(user-processes))
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(modules `((srfi srfi-1)
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(srfi srfi-26)
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(ice-9 popen) ;for the 'schedule' action
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(ice-9 rdelim)
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(ice-9 match)
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,@%default-modules))
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(start #~(make-forkexec-constructor
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(list (string-append #$mcron "/bin/mcron") #$@files)
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;; Disable auto-compilation of the job files and set a
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;; sane value for 'PATH'.
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#:environment-variables
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(cons* "GUILE_AUTO_COMPILE=0"
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"PATH=/run/current-system/profile/bin"
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(remove (cut string-prefix? "PATH=" <>)
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(environ)))
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#:log-file "/var/log/mcron.log"))
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(stop #~(make-kill-destructor))
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(actions
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(list (shepherd-schedule-action mcron files)))))))))
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(define mcron-service-type
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(service-type (name 'mcron)
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(extensions
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(list (service-extension shepherd-root-service-type
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mcron-shepherd-services)
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(service-extension profile-service-type
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(compose list
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mcron-configuration-mcron))))
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(compose concatenate)
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(extend (lambda (config jobs)
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(mcron-configuration
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(inherit config)
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(jobs (append (mcron-configuration-jobs config)
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jobs)))))
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(default-value (mcron-configuration)))) ;empty job list
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(define-deprecated (mcron-service jobs #:optional (mcron mcron))
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mcron-service-type
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"Return an mcron service running @var{mcron} that schedules @var{jobs}, a
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list of gexps denoting mcron job specifications.
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This is a shorthand for:
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@example
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(service mcron-service-type
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(mcron-configuration (mcron mcron) (jobs jobs)))
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@end example
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"
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(service mcron-service-type
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(mcron-configuration (mcron mcron) (jobs jobs))))
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;;; mcron.scm ends here
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