[bug#27855] [PATCH] gnu: Add rsync service.

[Oleg Pykhalov]

Hello Christopher,

Christopher Baines <address@hidden> writes:

> On Sat, 29 Jul 2017 14:03:49 +0300
> Oleg Pykhalov <address@hidden> wrote:
>
>> >> address@hidden {Scheme Variable} rsync-service-type
>> >> +This is the type for the @uref{https://rsync.samba.org} rsync
>> >> daemon, address@hidden record as in this example:
>> >> +
>> >> address@hidden
>> >> +(service rsync-service-type
>> >> +         (rsync-configuration))
>> >> address@hidden example
>> >> +
>> >> +See below for details about @code{rsync-configuration}.
>> >> address@hidden deffn
>> >> +
>> >> address@hidden {Data Type} rsync-configuration
>> >> +Data type representing the configuration for @code{rsync-service}.
>> >> +
>> >> address@hidden @asis
>> >> address@hidden @code{package} (default: @var{rsync})
>> >> +Package object of the Rsync utility for efficiently transferring
>> >> and +synchronizing files.  
>> >
>> > Object doesn't really fit here, if anything its a record. Also, I
>> > don't think this needs a description of what rsync does, it's
>> > probably clearest to just say that this is the rsync package?  
>> 
>> OK, is it good?
>> 
>>     @code{rsync} package to use.
>
> Yep, in my opinion, that is the right amount of information.
>
>> >> +(define (rsync-config-file config)
>> >> +  "Return the rsync configuration file corresponding to CONFIG."
>> >> +  (computed-file
>> >> +   "rsync.conf"
>> >> +   #~(begin
>> >> +       (call-with-output-file #$output
>> >> +         (lambda (port)
>> >> +           (display "# Generated by 'rsync-service'.\n" port)
>> >> +           (format port "pid file = ~a\n"
>> >> +                   #$(rsync-configuration-pid-file config))
>> >> +           (format port "lock file = ~a\n"
>> >> +                   #$(rsync-configuration-lock-file config))
>> >> +           (format port "log file = ~a\n"
>> >> +                   #$(rsync-configuration-log-file config))
>> >> +           (format port "port = ~a\n"
>> >> +                   #$(number->string
>> >> +                      (rsync-configuration-port-number config)))
>> >> +           (format port "use chroot = ~a\n"
>> >> +                   #$(if (rsync-configuration-use-chroot? config)
>> >> +                         "true" "false"))
>> >> +           (display "[files]\n" port)
>> >> +           (format port "path = ~a\n"
>> >> +                   #$(rsync-configuration-share-path config))
>> >> +           (format port "comment = ~a\n"
>> >> +                   #$(rsync-configuration-share-comment config))
>> >> +           (format port "read only = ~a\n"
>> >> +                   #$(if (rsync-configuration-read-only? config)
>> >> +                         "true" "false"))
>> >> +           (format port "timeout = ~a\n"
>> >> +                   #$(number->string
>> >> +                      (rsync-configuration-timeout config)))
>> >> +           #t)))))  
>> >
>> > It might be neater here to use mixed-text-file here. It might look
>> > something like...
>> >
>> > (define (rsync-config-file config)
>> >   "Return the rsync configuration file corresponding to CONFIG."
>> >   (match config
>> >     (($ <rsync-configuration> package port-number pid-file lock-file
>> >                               log-file use-chroot? share-path
>> >                               share-comment read-only? timeout)
>> >      (mixed text-file "rsync.conf"
>> >       "# Generated by 'rsync-service'.\n"
>> >       "pid file = " pid-file "\n"
>> >       "lock file = " lock-file "\n"
>> >       "log file = " log-file "\n"
>> >       "port = " (number->string port-number) "\n"
>> >       "use chroot = " (if use-chroot? "true" "false") "\n"
>> >       "[files]\n"
>> >       "path = " share-path "\n"
>> >       "comment = " share-comment "\n"
>> >       "read only = " (if read-only? "true" "false") "\n"
>> >       "timeout = " (number->string timeout) "\n"))))

OK, patched.

>> > One thing I tried with the Tailon service, was to define a
>> > gexp-compiler for the record type representing the configuration
>> > file. One really big advantage in the case of Tailon is that it
>> > easily allows the use of a custom file, just by providing a
>> > different gexp.  
>> 
>> So, this way you could provide your existing Tailon config as a file
>> in system declaration?  Nice.
>
> Yep, I think something like the following should just work, but I
> haven't tested it yet.
>
>   (service tailon-service-type
>            (tailon-configuration
>              (config-file (local-file "../tailon.yml"))))
>
> I bring this up, as I think it is great if this is a feature of all
> services, I'm having trouble though working out how you might do that
> in this case, with the use of values in the activation service
> extension. I can see complicated approaches, but nothing simple and
> clear enough.

I tried to apply your work in tailon service, but I have troubles as you
described.  So I just cleaned up code little bit.

>From 2cbbf8a9bf36edb153e04445bb8d52cd056d2767 Mon Sep 17 00:00:00 2001
From: Oleg Pykhalov <address@hidden>
Date: Thu, 3 Aug 2017 18:12:48 +0300
Subject: [PATCH] services: rsync: Clean up code.

* gnu/services/rsync.scm: Clean up.
---
 gnu/services/rsync.scm | 175 +++++++++++++++++++++----------------------------
 1 file changed, 75 insertions(+), 100 deletions(-)

diff --git a/gnu/services/rsync.scm b/gnu/services/rsync.scm
index 9cf2bc89a..e1a014a63 100644
--- a/gnu/services/rsync.scm
+++ b/gnu/services/rsync.scm
@@ -32,61 +32,59 @@
             rsync-configuration?
             rsync-service-type))
 
+;;;; Commentary:
 ;;;
-;;; Rsync.
+;;; This module implements a service that to run instance of Rsync,
+;;; files synchronization tool.
 ;;;
+;;;; Code:
 
 (define-record-type* <rsync-configuration>
   rsync-configuration make-rsync-configuration
   rsync-configuration?
-  ;; <package>
-  (package rsync-configuration-package
-           (default rsync))
-  ;; integer
-  (port-number rsync-configuration-port-number
-               (default 873))
-  ;; string
-  (pid-file rsync-configuration-pid-file
-            (default "/var/run/rsyncd.pid"))
-  ;; string
-  (lock-file rsync-configuration-lock-file
-             (default "/var/run/rsyncd.lock"))
-  ;; string
-  (log-file rsync-configuration-log-file
-            (default "/var/log/rsyncd.log"))
-  ;; Boolean
-  (use-chroot? rsync-configuration-use-chroot?
-               (default #f))
-  ;; string
-  (share-path rsync-configuration-share-path
-              (default "/srv/rsync"))
-  ;; string
-  (share-comment rsync-configuration-share-comment
+  (package       rsync-configuration-package ;package
+                 (default rsync))
+  (port-number   rsync-configuration-port-number ;integer
+                 (default 873))
+  (pid-file      rsync-configuration-pid-file ;string
+                 (default "/var/run/rsyncd.pid"))
+  (lock-file     rsync-configuration-lock-file ;string
+                 (default "/var/run/rsyncd.lock"))
+  (log-file      rsync-configuration-log-file ;string
+                 (default "/var/log/rsyncd.log"))
+  (use-chroot?   rsync-configuration-use-chroot? ;boolean
+                 (default #f))
+  (share-path    rsync-configuration-share-path ;string
+                 (default "/srv/rsync"))
+  (share-comment rsync-configuration-share-comment ;string
                  (default "Rsync share"))
-  ;; Boolean
-  (read-only? rsync-configuration-read-only?
-              (default #f))
-  ;; integer
-  (timeout rsync-configuration-timeout
-           (default 300)))
+  (read-only?    rsync-configuration-read-only? ;boolean
+                 (default #f))
+  (timeout       rsync-configuration-timeout ;integer
+                 (default 300))
+  (user          rsync-configuration-user ;string
+                 (default "rsyncd"))
+  (group         rsync-configuration-group ;string
+                 (default "rsyncd")))
 
-(define %rsync-accounts
-  ;; User account and group for rsync.
-  (list (user-group (name "rsyncd") (system? #t))
-        (user-account
-         (name "rsyncd")
-         (system? #t)
-         (group "rsyncd")
-         (comment "rsyncd privilege separation user")
-         (home-directory "/var/run/rsyncd")
-         (shell #~(string-append #$shadow "/sbin/nologin")))))
+(define (rsync-account config)
+  "Return the user accounts and user groups for CONFIG."
+  (let ((rsync-user (rsync-configuration-user config)))
+    (list (user-group (name "rsyncd") (system? #t))
+          (user-account
+           (name rsync-user)
+           (system? #t)
+           (group rsync-user)
+           (comment "rsyncd privilege separation user")
+           (home-directory "/var/run/rsyncd")
+           (shell #~(string-append #$shadow "/sbin/nologin"))))))
 
 (define (rsync-activation config)
   "Return the activation GEXP for CONFIG."
   #~(begin
       (use-modules (guix build utils))
       (let ((share-directory #$(rsync-configuration-share-path config))
-            (user (getpw "rsyncd")))
+            (user (getpw #$(rsync-configuration-user config))))
         (and=> share-directory mkdir-p)
         (chown share-directory
                (passwd:uid user)
@@ -94,70 +92,47 @@
 
 (define (rsync-config-file config)
   "Return the rsync configuration file corresponding to CONFIG."
-  (computed-file
-   "rsync.conf"
-   #~(begin
-       (call-with-output-file #$output
-         (lambda (port)
-           (display "# Generated by 'rsync-service'.\n" port)
-           (format port "pid file = ~a\n"
-                   #$(rsync-configuration-pid-file config))
-           (format port "lock file = ~a\n"
-                   #$(rsync-configuration-lock-file config))
-           (format port "log file = ~a\n"
-                   #$(rsync-configuration-log-file config))
-           (format port "port = ~a\n"
-                   #$(number->string
-                      (rsync-configuration-port-number config)))
-           (format port "use chroot = ~a\n"
-                   #$(if (rsync-configuration-use-chroot? config)
-                         "true" "false"))
-           (display "gid = rsyncd\n" port)
-           (display "[files]\n" port)
-           (format port "path = ~a\n"
-                   #$(rsync-configuration-share-path config))
-           (format port "comment = ~a\n"
-                   #$(rsync-configuration-share-comment config))
-           (format port "read only = ~a\n"
-                   #$(if (rsync-configuration-read-only? config)
-                         "true" "false"))
-           (format port "timeout = ~a\n"
-                   #$(number->string
-                      (rsync-configuration-timeout config)))
-           #t)))))
+  (match config
+    (($ <rsync-configuration> package port-number pid-file
+                              lock-file log-file use-chroot? share-path
+                              share-comment read-only? timeout user group)
+     (mixed-text-file "rsync.conf"
+                      "# Generated by 'rsync-service'.\n"
+                      "pid file = " pid-file "\n"
+                      "lock file = " lock-file "\n"
+                      "log file = " log-file "\n"
+                      "port = " (number->string port-number) "\n"
+                      "use chroot = " (if use-chroot? "true" "false") "\n"
+                      "gid = " group "\n"
+                      "[files]\n"
+                      "path = " share-path "\n"
+                      "comment = " share-comment "\n"
+                      "read only = " (if read-only? "true" "false") "\n"
+                      "timeout = " (number->string timeout) "\n"))))
 
 (define (rsync-shepherd-service config)
   "Return a <shepherd-service> for rsync with CONFIG."
-
-  (define rsync-command
-    #~(list (string-append #$(rsync-configuration-package config) "/bin/rsync")
-            "--daemon" "--config" #$(rsync-config-file config)))
-
-  (define pid-file
-    (rsync-configuration-pid-file config))
-
-  (define user
-    (let ((port (rsync-configuration-port-number config)))
-      (if (> port  1024)
-          "rsyncd"
-          "root")))
-
-  (list (shepherd-service
-         (provision '(rsync))
-         (documentation "Run rsync daemon.")
-         (start #~(make-forkexec-constructor #$rsync-command
-                                             #:pid-file #$pid-file
-                                             #:user #$user
-                                             #:group #$user))
-         (stop #~(make-kill-destructor)))))
+  (let* ((rsync (rsync-configuration-package config))
+         (pid-file (rsync-configuration-pid-file config))
+         (port (rsync-configuration-port-number config))
+         (user (if (> port  1024) (rsync-configuration-user config) "root")))
+    (list (shepherd-service
+           (provision '(rsync))
+           (documentation "Run rsync daemon.")
+           (start #~(make-forkexec-constructor
+                     (list (string-append #$rsync "/bin/rsync")
+                           "--config" #$(rsync-config-file config)
+                           "--daemon")
+                     #:pid-file #$pid-file
+                     #:user #$user
+                     #:group #$user))
+           (stop #~(make-kill-destructor))))))
 
 (define rsync-service-type
   (service-type
    (name 'rsync)
    (extensions
-    (list (service-extension shepherd-root-service-type
-                             rsync-shepherd-service)
-          (service-extension account-service-type
-                             (const %rsync-accounts))
-          (service-extension activation-service-type
-                             rsync-activation)))))
+    (list (service-extension shepherd-root-service-type rsync-shepherd-service)
+          (service-extension account-service-type rsync-account)
+          (service-extension activation-service-type rsync-activation)))
+   (default-value (rsync-configuration))))
-- 
2.13.3