Package: guix-patches;
Reported by: Ludovic Courtès <ludo <at> gnu.org>
Date: Tue, 4 Feb 2025 22:54:02 UTC
Severity: normal
Done: Ludovic Courtès <ludo <at> gnu.org>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Ludovic Courtès <ludo <at> gnu.org> To: 76063 <at> debbugs.gnu.org Cc: Ludovic Courtès <ludo <at> gnu.org>, Ludovic Courtès <ludo <at> gnu.org>, Maxim Cournoyer <maxim.cournoyer <at> gmail.com> Subject: [bug#76063] [PATCH 1/3] services: Add ‘system-log’ Shepherd service. Date: Tue, 4 Feb 2025 23:57:47 +0100
* gnu/services/shepherd.scm (gexp-or-integer?)
(gexp-or-string?, gexp-or-string-or-false?): New procedures.
(system-log-configuration): New record type.
(shepherd-system-log-service-type): New variable.
* doc/guix.texi (Shepherd Services): Document it.
Change-Id: I1e29fe0977eb4f8026ee6a2d2f282e269c8c00b4
---
doc/guix.texi | 55 +++++++++++++++++++
gnu/services/shepherd.scm | 108 ++++++++++++++++++++++++++++++++++++++
2 files changed, 163 insertions(+)
diff --git a/doc/guix.texi b/doc/guix.texi
index bb5f29277f..f52d79d549 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -45757,6 +45757,61 @@ Shepherd Services
on the @code{timer} service.
@end defvar
+@cindex system log service, from Shepherd
+@cindex syslogd, Shepherd system log service
+@defvar shepherd-system-log-service-type
+This service implements a @dfn{system log}, reading messages
+applications send to @file{/dev/log} and writing them to files or
+terminals according to user-defined rules. It provides functionality
+traditionally implemented by @command{syslogd} programs.
+
+The value of services of this type must be a
+@code{system-log-configuration} record, as described below.
+@end defvar
+
+@c %start of fragment
+
+@deftp {Data Type} system-log-configuration
+Available @code{system-log-configuration} fields are:
+
+@table @asis
+@item @code{provision} (default: @code{(system-log syslogd)}) (type: list-of-symbols)
+The name(s) of the system log service.
+
+@item @code{requirement} (default: @code{(root-file-system)}) (type: list-of-symbols)
+Dependencies of the system log service.
+
+@item @code{kernel-log-file} (type: gexp-or-string-or-false)
+File from which kernel messages are read, @file{/dev/kmsg} by default.
+
+@item @code{message-destination} (default: @code{#f}) (type: gexp-or-false)
+This gexp must evaluate to a procedure that, when passed a log message,
+returns the list of files to write it to; @code{#f} is equivalent to
+using @code{(default-message-destination-procedure)}. @pxref{System Log
+Service,,, shepherd,The GNU Shepherd Manual}, for information on how to
+write that procedure.
+
+@item @code{date-format} (type: gexp-or-string)
+String or string-valued gexp providing a specifying how to format
+timestamps in log file. It must be a valid string for @code{strftime},
+including delimiting space---e.g., @code{"%c "} for a format identical
+to that of traditional syslogd implementations.
+
+@item @code{history-size} (type: gexp-or-integer)
+Number of logging messages kept in memory for the purposes of making
+them available to @command{herd status system-log}.
+
+@item @code{max-silent-time} (type: gexp-or-integer)
+Time after which a mark is written to log files if nothing was logged
+during that time frame.
+
+@end table
+
+@end deftp
+
+
+@c %end of fragment
+
@defvar %shepherd-root-service
This service represents PID <at> tie{}1.
@end defvar
diff --git a/gnu/services/shepherd.scm b/gnu/services/shepherd.scm
index 328bfbedff..bc31285cfb 100644
--- a/gnu/services/shepherd.scm
+++ b/gnu/services/shepherd.scm
@@ -31,6 +31,7 @@ (define-module (gnu services shepherd)
#:use-module ((guix diagnostics)
#:select (define-with-syntax-properties formatted-message))
#:use-module (gnu services)
+ #:use-module (gnu services configuration)
#:use-module (gnu services herd)
#:use-module (gnu packages admin)
#:use-module (ice-9 match)
@@ -84,6 +85,17 @@ (define-module (gnu services shepherd)
shepherd-timer-service-type
shepherd-transient-service-type
+ system-log-configuration
+ system-log-configuration?
+ system-log-configuration-provision
+ system-log-configuration-requirement
+ system-log-configuration-message-destination
+ system-log-configuration-date-format
+ system-log-configuration-history-size
+ system-log-configuration-max-silent-time
+
+ shepherd-system-log-service-type
+
assert-valid-graph))
;;; Commentary:
@@ -721,3 +733,99 @@ (define shepherd-transient-service-type
This runs @command{rsync} in the background, as a service that you can inspect
with @command{herd status} and stop with @command{herd stop}.")))
+
+
+;;;
+;;; System log.
+;;;
+
+(define (gexp-or-false? x)
+ (or (gexp? x) (not x)))
+
+(define (gexp-or-integer? x)
+ (or (gexp? x) (integer? x)))
+
+(define (gexp-or-string? x)
+ (or (gexp? x) (string? x)))
+
+(define (gexp-or-string-or-false? x)
+ (or (gexp-or-string? x) (not x)))
+
+(define-configuration system-log-configuration
+ (provision
+ (list-of-symbols '(system-log syslogd))
+ "The name(s) of the system log service."
+ empty-serializer)
+ (requirement
+ (list-of-symbols '(root-file-system))
+ "Dependencies of the system log service."
+ empty-serializer)
+ (kernel-log-file
+ (gexp-or-string-or-false #~(kernel-log-file))
+ "File from which kernel messages are read, @file{/dev/kmsg} by default."
+ empty-serializer)
+ (message-destination
+ (gexp-or-false #f)
+ "This gexp must evaluate to a procedure that, when passed a log message,
+returns the list of files to write it to; @code{#f} is equivalent to using
+@code{(default-message-destination-procedure)}. @pxref{System Log Service,,,
+shepherd, The GNU Shepherd Manual}, for information on how to write that
+procedure."
+ empty-serializer)
+ (date-format
+ (gexp-or-string #~default-logfile-date-format)
+ "String or string-valued gexp providing a specifying how to format
+timestamps in log file. It must be a valid string for @code{strftime},
+including delimiting space---e.g., @code{\"%c \"} for a format identical to
+that of traditional syslogd implementations."
+ empty-serializer)
+ (history-size
+ (gexp-or-integer #~(default-log-history-size))
+ "Number of logging messages kept in memory for the purposes of making them
+available to @command{herd status system-log}."
+ empty-serializer)
+ (max-silent-time
+ (gexp-or-integer #~(default-max-silent-time))
+ "Time after which a mark is written to log files if nothing was logged
+during that time frame."
+ empty-serializer))
+
+(define shepherd-system-log-service-type
+ (shepherd-service-type
+ 'shepherd-system-log
+ (lambda (config)
+ (shepherd-service
+ (documentation "Shepherd's built-in system log (syslogd).")
+ (provision (system-log-configuration-provision config))
+ (requirement (system-log-configuration-requirement config))
+ (modules '((shepherd service system-log)
+ ((shepherd support) #:select (default-logfile-date-format))
+ ((shepherd logger) #:select (default-log-history-size))))
+ (free-form
+ #~(system-log-service #:provision
+ '#$(system-log-configuration-provision config)
+ #:requirement
+ '#$(system-log-configuration-requirement config)
+
+ ;; XXX: As of Shepherd 1.0.1,
+ ;; 'default-message-destination-procedure' is not
+ ;; exported, hence this conditional.
+ #$@(match (system-log-configuration-message-destination
+ config)
+ (#f #~())
+ (value #~(#:message-destination #$value)))
+
+ #:date-format
+ #$(system-log-configuration-date-format
+ config)
+ #:history-size
+ #$(system-log-configuration-history-size config)
+ #:max-silent-time
+ #$(system-log-configuration-max-silent-time
+ config)))))
+ (system-log-configuration)
+ (description
+ "The Shepherd's @code{system-log} service plays the role of traditional
+@command{syslogd} daemons, reading data logged by daemons to @file{/dev/log}
+and writing it to several files in @file{/var/log} according to user-provided
+dispatching rules.")))
--
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Copyright (C) 1999 Darren O. Benham,
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1994-97 Ian Jackson.