home-services: Add Mcron.

* gnu/home-services/mcron.scm: New file.
* gnu/local.mk: Add this.
* doc/guix.texi: Add documentation about Mcron Home Service.

Signed-off-by: Oleg Pykhalov <go.wigust@gmail.com>

1 files changed, 115 insertions, 0 deletions

diff --git a/gnu/home-services/mcron.scm b/gnu/home-services/mcron.scm
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+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2021 Andrew Tropin <andrew@trop.in>
+;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
+;;;
+;;; 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 home-services mcron)
+  #:use-module (gnu packages guile-xyz)
+  #:use-module (gnu home-services)
+  #:use-module (gnu home-services shepherd)
+  #:use-module (gnu services shepherd)
+  #:use-module (guix records)
+  #:use-module (guix gexp)
+  #:use-module (srfi srfi-1)
+  #:use-module (ice-9 match)
+
+  #:export (home-mcron-configuration
+            home-mcron-service-type))
+
+;;; Commentary:
+;;
+;; Service for the GNU mcron cron job manager.
+;;
+;; Example configuration, the first job runs mbsync once every ten
+;; minutes, the second one writes "Mcron service" to ~/mcron-file once
+;; every minute.
+;;
+;; (service home-mcron-service-type
+;;            (home-mcron-configuration
+;;             (jobs (list #~(job '(next-minute
+;;                                  (range 0 60 10))
+;;                                (lambda ()
+;;                                  (system* "mbsync" "--all")))
+;;                         #~(job next-minute-from
+;;                                (lambda ()
+;;                                  (call-with-output-file (string-append (getenv "HOME")
+;;                                                                        "/mcron-file")
+;;                                    (lambda (port)
+;;                                      (display "Mcron service" port)))))))))
+;;
+;;; Code:
+
+(define-record-type* <home-mcron-configuration> home-mcron-configuration
+  make-home-mcron-configuration
+  home-mcron-configuration?
+  (package home-mcron-configuration-package ; package
+           (default mcron))
+  (jobs home-mcron-configuration-jobs   ; list of jobs
+        (default '())))
+
+(define job-files (@@ (gnu services mcron) job-files))
+(define shepherd-schedule-action
+  (@@ (gnu services mcron) shepherd-schedule-action))
+
+(define home-mcron-shepherd-services
+  (match-lambda
+    (($ <home-mcron-configuration> mcron '()) ; no jobs to run
+     '())
+    (($ <home-mcron-configuration> mcron jobs)
+     (let ((files (job-files mcron jobs)))
+       (list (shepherd-service
+              (documentation "User cron jobs.")
+              (provision '(mcron))
+              (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 #$(file-append mcron "/bin/mcron") #$@files)
+                        #:log-file (string-append
+                                    (or (getenv "XDG_LOG_HOME")
+                                        (format #f "~a/.local/var/log"
+                                                (getenv "HOME")))
+                                    "/mcron.log")))
+              (stop #~(make-kill-destructor))
+              (actions
+               (list (shepherd-schedule-action mcron files)))))))))
+
+(define home-mcron-profile (compose list home-mcron-configuration-package))
+
+(define (home-mcron-extend config jobs)
+  (home-mcron-configuration
+   (inherit config)
+   (jobs (append (home-mcron-configuration-jobs config)
+                 jobs))))
+
+(define home-mcron-service-type
+  (service-type (name 'home-mcron)
+                (extensions
+                 (list (service-extension
+                        home-shepherd-service-type
+                        home-mcron-shepherd-services)
+                       (service-extension
+                        home-profile-service-type
+                        home-mcron-profile)))
+                (compose concatenate)
+                (extend home-mcron-extend)
+                (default-value (home-mcron-configuration))
+                (description
+                 "Install and configure the GNU mcron cron job manager.")))