176 lines
7.0 KiB
Scheme
176 lines
7.0 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
|
|
;;; Copyright © 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
|
|
;;;
|
|
;;; This file is part of GNU Guix.
|
|
;;;
|
|
;;; GNU Guix is free software; you can redistribute it and/or modify it
|
|
;;; under the terms of the GNU General Public License as published by
|
|
;;; the Free Software Foundation; either version 3 of the License, or (at
|
|
;;; your option) any later version.
|
|
;;;
|
|
;;; GNU Guix is distributed in the hope that it will be useful, but
|
|
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
;;; GNU General Public License for more details.
|
|
;;;
|
|
;;; You should have received a copy of the GNU General Public License
|
|
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
(define-module (gnu services mcron)
|
|
#:use-module (gnu services)
|
|
#:use-module (gnu services shepherd)
|
|
#:use-module (gnu packages guile-xyz)
|
|
#:use-module (guix deprecation)
|
|
#:use-module (guix records)
|
|
#:use-module (guix gexp)
|
|
#:use-module (srfi srfi-1)
|
|
#:use-module (ice-9 match)
|
|
#:use-module (ice-9 vlist)
|
|
#:export (mcron-configuration
|
|
mcron-configuration?
|
|
mcron-configuration-mcron
|
|
mcron-configuration-jobs
|
|
|
|
mcron-service-type))
|
|
|
|
;;; Commentary:
|
|
;;;
|
|
;;; This module implements a service that to run instances of GNU mcron, a
|
|
;;; periodic job execution daemon. Example of a service:
|
|
;;
|
|
;; (service mcron-service-type
|
|
;; (mcron-configuration
|
|
;; (jobs (list #~(job next-second-from
|
|
;; (lambda ()
|
|
;; (call-with-output-file "/dev/console"
|
|
;; (lambda (port)
|
|
;; (display "hello!\n" port)))))))))
|
|
;;;
|
|
;;; Code:
|
|
|
|
(define-record-type* <mcron-configuration> mcron-configuration
|
|
make-mcron-configuration
|
|
mcron-configuration?
|
|
(mcron mcron-configuration-mcron ;file-like
|
|
(default mcron))
|
|
(jobs mcron-configuration-jobs ;list of <mcron-job>
|
|
(default '())))
|
|
|
|
(define (job-files mcron jobs)
|
|
"Return a list of file-like object for JOBS, a list of gexps."
|
|
(define (validated-file job)
|
|
;; This procedure behaves like 'scheme-file' but it runs 'mcron
|
|
;; --schedule' to detect any error in JOB.
|
|
(computed-file "mcron-job"
|
|
(with-imported-modules '((guix build utils))
|
|
#~(begin
|
|
(use-modules (guix build utils))
|
|
|
|
(call-with-output-file "prologue"
|
|
(lambda (port)
|
|
;; This prologue allows 'mcron --schedule' to
|
|
;; proceed no matter what #:user option is passed
|
|
;; to 'job'.
|
|
(write '(set! getpw
|
|
(const (getpwuid (getuid))))
|
|
port)))
|
|
|
|
(call-with-output-file "job"
|
|
(lambda (port)
|
|
(write '#$job port)))
|
|
|
|
(invoke #+(file-append mcron "/bin/mcron")
|
|
"--schedule=20" "prologue" "job")
|
|
(copy-file "job" #$output)))
|
|
#:options '(#:env-vars (("COLUMNS" . "150")))))
|
|
|
|
(map validated-file jobs))
|
|
|
|
(define (shepherd-schedule-action mcron files)
|
|
"Return a Shepherd action that runs MCRON with '--schedule' for the given
|
|
files."
|
|
(shepherd-action
|
|
(name 'schedule)
|
|
(documentation
|
|
"Display jobs that are going to be scheduled.")
|
|
(procedure
|
|
#~(lambda* (_ #:optional (n "5"))
|
|
;; XXX: This is a global side effect.
|
|
(setenv "GUILE_AUTO_COMPILE" "0")
|
|
|
|
;; Run 'mcron' in a pipe so we can explicitly redirect its output to
|
|
;; 'current-output-port', which at this stage is bound to the client
|
|
;; connection.
|
|
(let ((pipe (open-pipe* OPEN_READ
|
|
#$(file-append mcron "/bin/mcron")
|
|
(string-append "--schedule=" n)
|
|
#$@files)))
|
|
(let loop ()
|
|
(match (read-line pipe 'concat)
|
|
((? eof-object?)
|
|
(catch 'system-error
|
|
(lambda ()
|
|
(zero? (close-pipe pipe)))
|
|
(lambda args
|
|
;; There's a race with the SIGCHLD handler, which
|
|
;; could call 'waitpid' before 'close-pipe' above does. If
|
|
;; we get ECHILD, that means we lost the race, but that's
|
|
;; fine.
|
|
(or (= ECHILD (system-error-errno args))
|
|
(apply throw args)))))
|
|
(line
|
|
(display line)
|
|
(loop)))))))))
|
|
|
|
(define mcron-shepherd-services
|
|
(match-lambda
|
|
(($ <mcron-configuration> mcron ()) ;nothing to do!
|
|
'())
|
|
(($ <mcron-configuration> mcron jobs)
|
|
(let ((files (job-files mcron jobs)))
|
|
(list (shepherd-service
|
|
(provision '(mcron))
|
|
(requirement '(user-processes))
|
|
(modules `((srfi srfi-1)
|
|
(srfi srfi-26)
|
|
(ice-9 popen) ;for the 'schedule' action
|
|
(ice-9 rdelim)
|
|
(ice-9 match)
|
|
,@%default-modules))
|
|
(start #~(make-forkexec-constructor
|
|
(list (string-append #$mcron "/bin/mcron") #$@files)
|
|
|
|
;; Disable auto-compilation of the job files and set a
|
|
;; sane value for 'PATH'.
|
|
#:environment-variables
|
|
(cons* "GUILE_AUTO_COMPILE=0"
|
|
"PATH=/run/current-system/profile/bin"
|
|
(remove (cut string-prefix? "PATH=" <>)
|
|
(environ)))
|
|
|
|
#:log-file "/var/log/mcron.log"))
|
|
(stop #~(make-kill-destructor))
|
|
|
|
(actions
|
|
(list (shepherd-schedule-action mcron files)))))))))
|
|
|
|
(define mcron-service-type
|
|
(service-type (name 'mcron)
|
|
(description
|
|
"Run the mcron job scheduling daemon.")
|
|
(extensions
|
|
(list (service-extension shepherd-root-service-type
|
|
mcron-shepherd-services)
|
|
(service-extension profile-service-type
|
|
(compose list
|
|
mcron-configuration-mcron))))
|
|
(compose concatenate)
|
|
(extend (lambda (config jobs)
|
|
(mcron-configuration
|
|
(inherit config)
|
|
(jobs (append (mcron-configuration-jobs config)
|
|
jobs)))))
|
|
(default-value (mcron-configuration)))) ;empty job list
|
|
|
|
;;; mcron.scm ends here
|