From: Nikita Karetnikov <nikita@karetnikov.org>
To: bug-guix@gnu.org
Subject: Re: guix-package --roll-back
Date: Sat, 29 Dec 2012 18:09:52 -0500 [thread overview]
Message-ID: <874nj4sbfe.fsf@karetnikov.org> (raw)
In-Reply-To: <871uejyq9z.fsf@karetnikov.org> (Nikita Karetnikov's message of "Sat, 22 Dec 2012 02:49:28 +0400")
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Hi,
I've slightly changed the 'roll-back' function. Now it prints an
informative message. And it's also possible to call it from a
command-line.
# ./pre-inst-env guix-package --roll-back
guix-package: switching from generation 6 to 5
The only problem I see is the following line.
(error "there are no other profiles.")
It will print an ugly backtrace if there are no other profiles. I'm
trying to understand how to handle it in a non-ugly way.
Any comments are appreciated.
Nikita
[-- Attachment #1.2: guix-package.diff --]
[-- Type: text/x-diff, Size: 4115 bytes --]
--- guix-package-orig 2012-12-29 22:19:46.000000000 +0000
+++ guix-package 2012-12-29 22:42:41.000000000 +0000
@@ -13,6 +13,7 @@
!#
;;; Guix --- Nix package management from Guile. -*- coding: utf-8 -*-
;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright (C) 2012 Nikita Karetnikov <nikita@karetnikov.org>
;;;
;;; This file is part of Guix.
;;;
@@ -87,13 +88,14 @@
(_
(error "unsupported manifest format" manifest))))
+(define (profile-rx profile)
+ "Return a regular expression that matches PROFILE's name and number."
+ (make-regexp (string-append "^" (regexp-quote (basename profile))
+ "-([0-9]+)")))
+
(define (latest-profile-number profile)
"Return the identifying number of the latest generation of PROFILE.
PROFILE is the name of the symlink to the current generation."
- (define %profile-rx
- (make-regexp (string-append "^" (regexp-quote (basename profile))
- "-([0-9]+)")))
-
(define* (scandir name #:optional (select? (const #t))
(entry<? (@ (ice-9 i18n) string-locale<?)))
;; XXX: Bug-fix version introduced in Guile v2.0.6-62-g139ce19.
@@ -129,7 +131,7 @@
(sort files entry<?))))
(match (scandir (dirname profile)
- (cut regexp-exec %profile-rx <>))
+ (cut regexp-exec (profile-rx profile) <>))
(#f ; no profile directory
0)
(() ; no profiles
@@ -137,7 +139,7 @@
((profiles ...) ; former profiles around
(let ((numbers (map (compose string->number
(cut match:substring <> 1)
- (cut regexp-exec %profile-rx <>))
+ (cut regexp-exec (profile-rx profile) <>))
profiles)))
(fold (lambda (number highest)
(if (> number highest)
@@ -177,6 +179,31 @@
packages)
#:modules '((guix build union))))
+(define (profile-number profile)
+ "Return PROFILE's number. PROFILE should be an absolute filename."
+ (match:substring (regexp-exec (profile-rx profile)
+ (basename (readlink profile))) 1))
+
+(define (roll-back)
+ "Roll back to the previous profile."
+ (let* ((current-profile-number
+ (string->number (profile-number %current-profile)))
+ (previous-profile-number (number->string (1- current-profile-number)))
+ (previous-profile
+ (string-append %current-profile "-"
+ previous-profile-number "-link")))
+
+ (define (switch)
+ "Switch to the previous generation."
+ (simple-format #t "guix-package: switching from generation ~a to ~a~%"
+ current-profile-number previous-profile-number)
+ (delete-file %current-profile)
+ (symlink previous-profile %current-profile))
+
+ (if (= current-profile-number 1)
+ (error "there are no other profiles.") ; XXX: handle this error
+ (switch))))
+
\f
;;;
;;; Command-line options.
@@ -201,6 +228,8 @@
(display (_ "
-n, --dry-run show what would be done without actually doing it"))
(display (_ "
+ --roll-back roll back to the previous generation"))
+ (display (_ "
-b, --bootstrap use the bootstrap Guile to build the profile"))
(display (_ "
--verbose produce verbose output"))
@@ -236,6 +265,10 @@
(option '(#\r "remove") #t #f
(lambda (opt name arg result)
(alist-cons 'remove arg result)))
+ (option '("roll-back") #f #f
+ (lambda args
+ (roll-back)
+ (exit 0)))
(option '(#\p "profile") #t #f
(lambda (opt name arg result)
(alist-cons 'profile arg
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next prev parent reply other threads:[~2012-12-29 23:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-21 22:49 guix-package --roll-back Nikita Karetnikov
2012-12-29 23:09 ` Nikita Karetnikov [this message]
2012-12-29 23:13 ` Andreas Enge
2012-12-30 15:30 ` Ludovic Courtès
2013-01-01 13:57 ` Nikita Karetnikov
2013-01-01 22:58 ` Ludovic Courtès
2013-01-03 5:42 ` Nikita Karetnikov
2013-01-03 14:41 ` Ludovic Courtès
2013-01-04 18:18 ` Nikita Karetnikov
2013-01-05 19:20 ` Ludovic Courtès
2013-01-09 19:04 ` Nikita Karetnikov
2013-01-10 15:01 ` Nikita Karetnikov
2013-01-10 22:26 ` Ludovic Courtès
2013-01-11 5:48 ` Nikita Karetnikov
2013-01-11 13:39 ` Ludovic Courtès
2013-01-12 21:03 ` Nikita Karetnikov
2013-01-13 20:40 ` Ludovic Courtès
2013-01-16 21:34 ` Nikita Karetnikov
2013-01-17 21:47 ` Ludovic Courtès
2013-01-21 5:50 ` Nikita Karetnikov
2013-01-22 21:37 ` Ludovic Courtès
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