1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016-2020, 2023 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2022 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;; Copyright © 2023 Bruno Victal <mirai@makinata.eu>
;;;
;;; 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 configuration) #:select
(define-configuration/no-serialization))
#:use-module (gnu services shepherd)
#:use-module (gnu system privilege)
#:use-module (gnu packages guile-xyz)
#:use-module ((guix packages) #:select (package?))
#: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-configuration-log?
mcron-configuration-log-file
mcron-configuration-log-format
mcron-configuration-date-format
mcron-configuration-home-service?
mcron-service-type
cron-daemon-configuration
cron-daemon-configuration-cron
cron-daemon-configuration-
cron-daemon-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:
;; Configuration of mcron.
;; XXX: 'define-configuration' cannot be used here due to the need for
;; 'thunked' and 'innate' fields as well as 'this-mcron-configuration'.
(define-record-type* <mcron-configuration> mcron-configuration
make-mcron-configuration
mcron-configuration?
this-mcron-configuration
(mcron mcron-configuration-mcron ;file-like
(default mcron))
(jobs mcron-configuration-jobs ;list of gexps
(default '()))
(log? mcron-configuration-log? ;Boolean
(default #t))
(log-file mcron-configuration-log-file ;string | gexp
(thunked)
(default
(if (mcron-configuration-home-service?
this-mcron-configuration)
#~(string-append %user-log-dir "/mcron.log")
"/var/log/mcron.log")))
(log-format mcron-configuration-log-format ;string
(default "~1@*~a ~a: ~a~%"))
(date-format mcron-configuration-date-format ;string | #f
(default #f))
(home-service? mcron-configuration-home-service?
(default for-home?) (innate)))
(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 config)
(match-record config <mcron-configuration>
(mcron jobs log? log-file log-format date-format home-service?)
(if (eq? jobs '())
'() ;nothing to do
(let ((files (job-files mcron jobs)))
(list (shepherd-service
(provision '(mcron))
(requirement (if home-service?
'()
'(user-processes)))
(modules `((srfi srfi-1)
(srfi srfi-26)
(ice-9 popen) ;for the 'schedule' action
(ice-9 rdelim)
(ice-9 match)
((shepherd support) #:hide (mkdir-p)) ;for '%user-log-dir'
,@%default-modules))
(start #~(make-forkexec-constructor
(list #$(file-append mcron "/bin/mcron")
#$@(if log?
`("--log" "--log-format" ,log-format
,@(if date-format
(list "--date-format"
date-format)
'()))
'())
#$@files)
;; Disable auto-compilation of the job files and
;; set a sane value for 'PATH'.
#:environment-variables
(cons* "GUILE_AUTO_COMPILE=0"
#$(if home-service?
'(environ)
'(cons*
"PATH=/run/current-system/profile/bin"
(remove (cut string-prefix? "PATH=" <>)
(environ)))))
#:log-file #$log-file))
(stop #~(make-kill-destructor))
(actions
(list (shepherd-schedule-action mcron files)))))))))
(define mcron-service-type
(service-type (name 'mcron)
(description
"Run the mcron job scheduling daemon.")
(extensions
(list (service-extension shepherd-root-service-type
mcron-shepherd-services)
(service-extension profile-service-type
(compose list
mcron-configuration-mcron))))
(compose concatenate)
(extend (lambda (config jobs)
(mcron-configuration
(inherit config)
(home-service?
(mcron-configuration-home-service? config))
(jobs (append (mcron-configuration-jobs config)
jobs)))))
(default-value (mcron-configuration)))) ;empty job list
(define-configuration/no-serialization cron-daemon-configuration
(cron
(package mcron)
"The cron package to use.")
(monitor-etc?
(boolean #f)
"Whether to check /etc/crontab for updates."))
(define (cron-daemon-shepherd-services config)
(list (shepherd-service
(provision '(cron-daemon))
(start #~(make-forkexec-constructor
'(#$(file-append (cron-daemon-configuration-cron config)
"/sbin/cron")
#$@(if (cron-daemon-configuration-monitor-etc? config)
'()
'("--noetc")))
#:pid-file "/var/run/cron.pid"))
(stop #~(make-kill-destructor)))))
(define cron-daemon-activation
(const #~(mkdir-p "/var/cron/tabs")))
(define (cron-daemon-setuid-programs config)
(list (privileged-program
(program (file-append (cron-daemon-configuration-cron config)
"/sbin/crontab-access")))))
(define cron-daemon-service-type
(service-type (name 'cron-daemon)
(description
"Run the traditional cron daemon.")
(extensions
(list (service-extension shepherd-root-service-type
cron-daemon-shepherd-services)
(service-extension activation-service-type
cron-daemon-activation)
(service-extension privileged-program-service-type
cron-daemon-setuid-programs)))
(default-value (cron-daemon-configuration))))
;;; mcron.scm ends here
|
