Package: guix-patches;
Reported by: Bruno Victal <mirai <at> makinata.eu>
Date: Sun, 26 Mar 2023 18:19:02 UTC
Severity: normal
Tags: patch
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From: Bruno Victal <mirai <at> makinata.eu> To: 62465 <at> debbugs.gnu.org Cc: Bruno Victal <mirai <at> makinata.eu>, maxim.cournoyer <at> gmail.com Subject: [bug#62465] [PATCH v2 2/2] services: mcron: Add instance name support for mcron. Date: Wed, 29 Mar 2023 14:54:34 +0100
Allow running more than one mcron instance. Make log-file robust against operator error when provisioning an additional mcron instance but log-file is left at its default value. Follow-up to <https://issues.guix.gnu.org/62169>. * gnu/services/mcron.scm (mcron-configuration)[instance-name]: New field. [log-file]: Update description. (mcron-shepherd-services): Implement instance-name support. Make log-file robust against multiple instances writing to the same default log-file. * doc/guix.texi (Scheduled Job Execution): Update it. --- doc/guix.texi | 30 +++++++++++++++++++++++++++++- gnu/services/mcron.scm | 34 +++++++++++++++++++++++++++++----- 2 files changed, 58 insertions(+), 6 deletions(-) diff --git a/doc/guix.texi b/doc/guix.texi index 5a597cf122..ba80b9660c 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -19383,6 +19383,10 @@ Scheduled Job Execution This is a list of symbols naming Shepherd services that this service will depend on. +@item @code{instance} (type: maybe-symbol) +Set the shepherd service name to @code{mcron-@var{instance}}. This is +useful when you want to have more than one mcron instance. + @item @code{jobs} (default: @code{()}) (type: list-of-gexps) This is a list of gexps (@pxref{G-Expressions}), where each gexp corresponds to an mcron job specification (@pxref{Syntax, mcron job @@ -19392,7 +19396,9 @@ Scheduled Job Execution Log messages to standard output. @item @code{log-file} (default: @code{"/var/log/mcron.log"}) (type: string) -Log file location. +Log file location. When @var{instance} is set and @var{log-file} is +kept at its @emph{default value}, it will log to +@file{/var/log/mcron-@var{instance}.log}. @item @code{log-format} (default: @code{"~1@@*~a ~a: ~a~%"}) (type: string) @code{(ice-9 format)} format string for log messages. The default value @@ -19407,6 +19413,28 @@ Scheduled Job Execution @end deftp @c %end of fragment +Occasionally, it is desirable to run another mcron instance to separate +some of the jobs from the main mcron instance for clarity purposes, or if +the jobs are very chatty and frequent. (for example, a heartbeat check +every 30 seconds) + +The example below shows how an extra mcron service can be defined. +@lisp +(use (guix) + (guix records) + (gnu services) + (gnu services mcron)) + +(define secondary-mcron-service-type + (service-type + (inherit mcron-service-type) + (name 'mcron-secondary) + (default-value + (mcron-configuration + (instance 'secondary) + (log-file "/var/log/mcron-secondary.log"))))) +@end lisp + @node Log Rotation @subsection Log Rotation diff --git a/gnu/services/mcron.scm b/gnu/services/mcron.scm index 99eb0edd60..4d8ab4af2c 100644 --- a/gnu/services/mcron.scm +++ b/gnu/services/mcron.scm @@ -27,12 +27,14 @@ (define-module (gnu services mcron) #:use-module (guix records) #:use-module (guix gexp) #:use-module (srfi srfi-1) + #:use-module (ice-9 format) #:use-module (ice-9 match) #:use-module (ice-9 vlist) #:export (mcron-configuration mcron-configuration? mcron-configuration-mcron mcron-configuration-shepherd-requirement + mcron-configuration-instance mcron-configuration-jobs mcron-configuration-log? mcron-configuration-log-file @@ -63,6 +65,7 @@ (define list-of-symbols? (list-of symbol?)) (define-maybe/no-serialization string) +(define-maybe/no-serialization symbol) (define-configuration/no-serialization mcron-configuration (mcron @@ -74,6 +77,11 @@ (define-configuration/no-serialization mcron-configuration "This is a list of symbols naming Shepherd services that this service will depend on.") + (instance + maybe-symbol + "Set the shepherd service name to @code{mcron-@var{instance}}. +This is useful when you want to have more than one mcron instance.") + (jobs (list-of-gexps '()) "This is a list of gexps (@pxref{G-Expressions}), where each gexp @@ -86,7 +94,9 @@ (define-configuration/no-serialization mcron-configuration (log-file (string "/var/log/mcron.log") - "Log file location.") + "Log file location. When @var{instance} is set and @var{log-file} +is kept at its @emph{default value}, it will log to +@file{/var/log/mcron-@var{instance}.log}.") (log-format (string "~1@*~a ~a: ~a~%") @@ -167,12 +177,26 @@ (define (shepherd-schedule-action mcron files) (define (mcron-shepherd-services config) (match-record config <mcron-configuration> - (mcron shepherd-requirement jobs log? log-file log-format date-format) + (mcron shepherd-requirement instance + jobs log? log-file log-format date-format) (if (eq? jobs '()) '() ;nothing to do - (let ((files (job-files mcron jobs))) + (let* ((files (job-files mcron jobs)) + (instance-name + (format #f "mcron~@[-~a~]" (maybe-value instance))) + (service-name (string->symbol instance-name)) + ;; Make log-file robust against multiple instances + ;; attempting to write to the same file when + ;; left at its default value. + (default-log-file (mcron-configuration-log-file + (mcron-configuration))) + (log-file* (if (and (maybe-value-set? instance) + (equal? log-file default-log-file)) + (string-append (dirname default-log-file) + "/" instance-name ".log") + log-file))) (list (shepherd-service - (provision '(mcron)) + (provision (list service-name)) (requirement `(user-processes ,@shepherd-requirement)) (modules `((srfi srfi-1) (srfi srfi-26) @@ -199,7 +223,7 @@ (define (mcron-shepherd-services config) (remove (cut string-prefix? "PATH=" <>) (environ))) - #:log-file #$log-file)) + #:log-file #$log-file*)) (stop #~(make-kill-destructor)) (actions (list (shepherd-schedule-action mcron files))))))))) -- 2.39.1
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