Re: [PATCH] gnu: rottlog: rotate messages daily.

[Jan Nieuwenhuizen]

Ludovic Courtès writes:

Hi!

> The ‘rottlog-configuration’ is actually a macro.  So at every call site
> where a default value is used, the default value code is duplicated,
> leading to code bloat if that default value is a big expression.

Ah, ok.

>> I'm not sure if we should export the %default-rotations or if we should
>> describe their contents in the manual.
>
> Probably worth exporting and documenting, so people can ‘cons’ on it.

Ok.

>> +(define (syslog-rotation-config file)
>> + (let ((coreutils
>> "/gnu/store/56x9fvx59i300wav3c193h84cp80bslr-coreutils-8.25")) ;;
>> FIXME
>
> Good point…

Hmm... :-)

> I think we cannot use ‘plain-file’ here because of the computed ‘kill’
> file name.  So instead, this would be something along the lines of
> (moving ‘string-append’ from the host side to the build side):
>
>   (define (syslog-rotation-config file)
>     #~(string-append #$file " {\n" …
>                      #$coreutils "/bin/kill -HUP …"
>                      "}\n"))
>
> and:
>
>   (define %default-rotations
>     `(("weekly" ,(computed-file "rottlog.weekly"
>                                 #~(call-with-output-file #$output
>                                     (lambda (port)
>                                       (display #$(syslog-rotation-file …)
>                                                port)))))))
> HTH!

Yes, that helps a lot.  Attached a working version...I still feel like
fighting a bit with #~ and '#$...IWBN to get rid of `(apply append '#$(map',
usually append-map works for that, but the gexp boundary seems a bit too
tricksy for me here.

> Thanks again for taking the time and coping with half-baked advice!

Rotating my logs for quite some time already here, and learning quite
a bit about guix and scheme in the process too ;-)

Thanks!
Greetings,
Jan

>From f4b03963d6ba6a232fca4ed749695423547d0ad5 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <address@hidden>
Date: Thu, 8 Sep 2016 01:20:43 +0200
Subject: [PATCH] gnu: services: add rottlog.

* gnu/services/admin.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Log Rotation): Document it.
---
 doc/guix.texi          |  65 +++++++++++++++++++++++++-
 gnu/local.mk           |   1 +
 gnu/services/admin.scm | 122 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 187 insertions(+), 1 deletion(-)
 create mode 100644 gnu/services/admin.scm

diff --git a/doc/guix.texi b/doc/guix.texi
index d5ece55..3db3d28 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -26,7 +26,8 @@ Copyright @copyright{} 2016 Ben address@hidden
 Copyright @copyright{} 2016 Chris address@hidden
 Copyright @copyright{} 2016 Efraim address@hidden
 Copyright @copyright{} 2016 John address@hidden
-Copyright @copyright{} 2016 ng0
+Copyright @copyright{} 2016 address@hidden
+Copyright @copyright{} 2016 Jan Nieuwenhuizen
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -213,6 +214,7 @@ Services
 
 * Base Services::               Essential system services.
 * Scheduled Job Execution::     The mcron service.
+* Log Rotation::                The rottlog service.
 * Networking Services::         Network setup, SSH daemon, etc.
 * X Window::                    Graphical display.
 * Desktop Services::            D-Bus and desktop services.
@@ -7622,6 +7624,7 @@ declaration.
 @menu
 * Base Services::               Essential system services.
 * Scheduled Job Execution::     The mcron service.
+* Log Rotation::                The rottlog service.
 * Networking Services::         Network setup, SSH daemon, etc.
 * X Window::                    Graphical display.
 * Desktop Services::            D-Bus and desktop services.
@@ -8096,6 +8099,66 @@ specifications,, mcron, address@hidden).
 @end deftp
 
 
address@hidden Log Rotation
address@hidden Log Rotation
+
address@hidden rottlog
address@hidden log rotation
+The @code{(gnu services admin)} module provides an interface to
address@hidden, a log rotator @pxref{rottlog,,,GNU Rot[t]log Manual}.
+
+The example below defines an operating system that provides
+log rotation.
+
address@hidden
+(use-modules (guix) (gnu) (gnu services admin) (gnu services mcron))
+(use-package-modules base idutils)
+
+(operating-system
+  ;; @dots{}
+  (services (cons* (mcron-service)
+                   (service rottlog-service-type (rottlog-configuration)) 
+                   %base-services)))
address@hidden lisp
+
address@hidden {Scheme Variable} rottlog-service-type
+This is the type of the @code{rottlog} service, whose value is an
address@hidden object.
+
+This service type can define @var{mcron}-jobs (@pxref{Scheduled Job
+Execution}) to run the rottlog service.
address@hidden defvr
+
address@hidden {Data Type} rottlog-configuration
+Data type representing the configuration of rottlog.
+
address@hidden @asis
address@hidden @code{rottlog} (default: @var{rottlog})
+The rottlog package to use.
+
address@hidden @code{rc-file} (default: (file-append rottlog "/etc/rc")
+The rottlog @var{rc-file} to use.
+
address@hidden @code{periodic-rotations} (default: `(("weekly" 
%default-rotatations)))
+A list of rottlog period-name/period-config tuples.
+
address@hidden @code{jobs}
+This is a list of gexps (@pxref{G-Expressions}), where each gexp
+corresponds to an mcron job specification (@pxref{Syntax, mcron job
+specifications,, mcron, address@hidden).
address@hidden table
address@hidden deftp
+
address@hidden {Scheme Variable} %default-rotatations
+Specifies weekly rotation of @var{%rotated-files} and
address@hidden"/var/log/shepherd.log"}.
address@hidden defvr
+
address@hidden {Scheme Variable} %rotated-files
+The list of syslog-controlled files to be rotated (default:
+'("/var/log/messages" "/var/log/secure"))
address@hidden defvr
+
 @node Networking Services
 @subsubsection Networking Services
 
diff --git a/gnu/local.mk b/gnu/local.mk
index 0da41f7..baa10f9 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -381,6 +381,7 @@ GNU_SYSTEM_MODULES =                                \
   %D%/packages/zip.scm                         \
                                                \
   %D%/services.scm                             \
+  %D%/services/admin.scm                       \
   %D%/services/avahi.scm                       \
   %D%/services/base.scm                                \
   %D%/services/databases.scm                   \
diff --git a/gnu/services/admin.scm b/gnu/services/admin.scm
new file mode 100644
index 0000000..36ee997
--- /dev/null
+++ b/gnu/services/admin.scm
@@ -0,0 +1,122 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2016 Jan Nieuwenhuizen <address@hidden>
+;;;
+;;; 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 thye GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu services admin)
+  #:use-module (gnu packages admin)
+  #:use-module (gnu packages base)
+  #:use-module (gnu services)
+  #:use-module (gnu services mcron)
+  #:use-module (gnu services shepherd)
+  #:use-module (guix gexp)
+  #:use-module (guix packages)
+  #:use-module (guix records)
+  #:use-module (srfi srfi-1)
+  #:export (%default-rotations
+            %rotated-files
+            rottlog-configuration
+            rottlog-configuration?
+            rottlog-service
+            rottlog-service-type))
+
+;;; Commentary:
+;;;
+;;; This module implements configuration of rottlog by writing
+;;; /etc/rottlog/{rc,hourly|daily|weekly}.  Example usage
+;;; 
+;;;     (mcron-service)
+;;;     (service rottlog-service-typeo (rottlog-configuration))
+;;;
+;;; Code:
+
+(define %rotated-files
+  '("/var/log/messages" "/var/log/secure"))
+
+(define (syslog-rotation-config file)
+  #~(#$file " {
+       sharedscripts
+       postrotate
+       " #$coreutils "/bin/kill -HUP $(cat /var/run/syslog.pid) 2> /dev/null
+       endscript
+       nocompress
+}
+"))
+
+(define (simple-rotation-config file)
+  (string-append file " {
+       sharedscripts
+       postrotate
+       endscript
+       nocompress
+}
+"))
+
+(define %default-rotations
+  `(("weekly"
+     ,(computed-file "rottlog.weekly"
+                     #~(call-with-output-file #$output
+                         (lambda (port)
+                           (display
+                            (string-join
+                             (apply append '#$(map syslog-rotation-config
+                                                   %rotated-files))
+                             "")
+                            port)
+                           (display #$(simple-rotation-config
+                                       "/var/log/shepherd.log")
+                                    port)))))))
+
+(define (default-jobs rottlog)
+  (list #~(job
+           '(next-hour '(0))
+           (lambda ()
+             (system* (strinng-append #$rottlog "/sbin/rottlog"))))
+        #~(job
+           '(next-hour '(12))
+           (lambda ()
+             (system* (string-append #$rottlog "/sbin/rottlog"))))))
+
+(define-record-type* <rottlog-configuration>
+  rottlog-configuration make-rottlog-configuration
+  rottlog-configuration?
+  (rottlog            rottlog-rottlog            ; package
+                      (default rottlog))
+  (rc-file            rottlog-rc-file            ; file
+                      (default (file-append rottlog "/etc/rc")))
+  (periodic-rotations rottlog-periodic-rotations ; list of (name file) tuples
+                      (default %default-rotations))
+  (jobs               rottlog-jobs               ; list of <mcron-job>
+                      (default #f)))
+
+(define (rottlog-etc config)
+  `(("rottlog" ,(file-union "rottlog"
+                            (cons `("rc" ,(rottlog-rc-file config))
+                                  (rottlog-periodic-rotations config))))))
+
+(define (rottlog-jobs-or-default config)
+  (or (rottlog-jobs config)
+      (default-jobs (rottlog-rottlog config))))
+
+(define rottlog-service-type
+  (service-type
+   (name 'rottlog)
+   (extensions
+    (list
+     (service-extension etc-service-type rottlog-etc)
+     (service-extension mcron-service-type rottlog-jobs-or-default)))))
+
+;;; admin.scm ends here
-- 
2.9.3

-- 
Jan Nieuwenhuizen <address@hidden> | GNU LilyPond http://lilypond.org
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