From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Kost Subject: Re: [PATCH] guix package: Add '--switch-generation' option. Date: Tue, 07 Oct 2014 14:04:51 +0400 Message-ID: <87y4ssi4ak.fsf@gmail.com> References: <87k3719v7p.fsf@gmail.com> <87r419fa50.fsf@gnu.org> <87fvho9fqm.fsf@gmail.com> <87a97taixl.fsf@gmail.com> <87sil2rbly.fsf@gnu.org> <87tx5idn7f.fsf_-_@gmail.com> <87egwlkcy1.fsf@gnu.org> <87ppg5el2i.fsf@gmail.com> <87d2c5h4if.fsf@gnu.org> <87lhqsev1d.fsf@gmail.com> <877g2c74xh.fsf@gnu.org> <87ha1gds3w.fsf@gmail.com> <8761hsmxkl.fsf@gnu.org> <87zjf4d1mh.fsf@gmail.com> <87mwb0b3fq.fsf@gnu.org> <87ha17ctyv.fsf_-_@gmail.com> <87ppfs6gxk.fsf@gnu.org> <87wq8fk979.fsf_-_@gmail.com> <87eguninyx.fsf@gnu.org> <8738b1jndu.fsf_-_@gmail.com> <87ppe5vw1b.fsf@gnu.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:42571) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XbRdd-0007j1-Gn for guix-devel@gnu.org; Tue, 07 Oct 2014 06:05:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XbRdU-0007cn-2q for guix-devel@gnu.org; Tue, 07 Oct 2014 06:05:01 -0400 In-Reply-To: <87ppe5vw1b.fsf@gnu.org> ("Ludovic \=\?utf-8\?Q\?Court\=C3\=A8s\=22'\?\= \=\?utf-8\?Q\?s\?\= message of "Mon, 06 Oct 2014 21:27:12 +0200") List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org To: Ludovic =?utf-8?Q?Court=C3=A8s?= Cc: guix-devel@gnu.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Ludovic Court=C3=A8s (2014-10-06 23:27 +0400) wrote: > Alex Kost skribis: > >> A patch is attached. Some comments: >> >> - =E2=80=98shitted-generation=E2=80=99 is not a very good name, I think.= Ideas? > > =E2=80=98shifted-generation=E2=80=99 is better :-), but otherwise maybe > =E2=80=98relative-generation=E2=80=99? No strong opinion. I like =E2=80=98relative-generation=E2=80=99, thanks. >> - =E2=80=98previous-generation-number=E2=80=99 may use =E2=80=98shifted-= generation=E2=80=99 now: >> >> (define* (previous-generation-number profile #:optional >> (number (generation-number profile)= )) >> "Return the number of the generation before generation NUMBER of >> PROFILE, or 0 if none exists. It could be NUMBER - 1, but it's not the >> case when generations have been deleted (there are \"holes\")." >> (or (shifted-generation profile -1 number) >> 0)) >> >> Worth changing? > > Yes, why not. Done. >> - Perhaps it would be better to make 2 commits (?): one for adding >> =E2=80=98shifted-generation=E2=80=99 and =E2=80=98switch-to-generation= =E2=80=99 procedures to (guix >> profiles) and another is for adding the =E2=80=9C--switch-generation= =E2=80=9D option >> itself. > > Yes. Done. >> - Also I made a couple of cosmetic changes in =E2=80=9Cguix/scripts/pack= age.scm=E2=80=9D: >> * =E2=80=98filter-map=E2=80=99 was replaced by 'for-each' because it w= as called only for >> side effects there; >> * =E2=80=98begin=E2=80=99 was removed from =E2=80=98cond=E2=80=99. >> I think these changes do not deserve a separate commit and may stay in >> this patch. Is it OK? > > Several patches make it easier to reason about the changes, but it=E2=80= =99s OK > here. Your call. OK, thanks, I left those changes. >> From 3cc52d1aade5e9723c38c0af5fa4437cbdf1a9b6 Mon Sep 17 00:00:00 2001 >> From: Alex Kost >> Date: Mon, 6 Oct 2014 17:35:51 +0400 >> Subject: [PATCH] guix package: Add '--switch-generation' option. >> >> * doc/guix.texi (Invoking guix package): Update documentation. >> * guix/profiles.scm (shifted-generation, switch-to-generation): New >> procedures. >> * guix/scripts/package.scm: Add '--switch-generation' option. >> (switch-to-previous-generation): Use 'switch-to-generation'. > > Could you add a test in tests/guix-package.sh? > > The rest looks good to me, thanks for working on it! Thanks, I've added a couple of tests. The new patches are attached. Further improvements (documentation may be unsatisfactory)? --=-=-= Content-Type: text/x-diff Content-Disposition: attachment; filename=0001-profiles-Add-procedures-for-switching-generations.patch >From 9493421a4e094be6686ff6f28749946d491f81cd Mon Sep 17 00:00:00 2001 From: Alex Kost Date: Tue, 7 Oct 2014 11:50:44 +0400 Subject: [PATCH 1/2] profiles: Add procedures for switching generations. * guix/scripts/package.scm (switch-to-previous-generation): Move to... * guix/profiles.scm: ... here. Use 'switch-to-generation'. (relative-generation): New procedure. (previous-generation-number): Use it. (switch-to-generation): New procedure. --- guix/profiles.scm | 53 ++++++++++++++++++++++++++++++++++++++++-------- guix/scripts/package.scm | 9 -------- 2 files changed, 45 insertions(+), 17 deletions(-) diff --git a/guix/profiles.scm b/guix/profiles.scm index 18733a6..9920881 100644 --- a/guix/profiles.scm +++ b/guix/profiles.scm @@ -71,9 +71,12 @@ generation-number generation-numbers profile-generations + relative-generation previous-generation-number generation-time - generation-file-name)) + generation-file-name + switch-to-generation + switch-to-previous-generation)) ;;; Commentary: ;;; @@ -569,16 +572,28 @@ former profiles were found." '() generations))) -(define (previous-generation-number profile number) +(define* (relative-generation profile shift #:optional + (current (generation-number profile))) + "Return PROFILE's generation shifted from the CURRENT generation by SHIFT. +SHIFT is a positive or negative number. +Return #f if there is no such generation." + (let* ((abs-shift (abs shift)) + (numbers (profile-generations profile)) + (from-current (memq current + (if (negative? shift) + (reverse numbers) + numbers)))) + (and from-current + (< abs-shift (length from-current)) + (list-ref from-current abs-shift)))) + +(define* (previous-generation-number profile #:optional + (number (generation-number profile))) "Return the number of the generation before generation NUMBER of PROFILE, or 0 if none exists. It could be NUMBER - 1, but it's not the case when generations have been deleted (there are \"holes\")." - (fold (lambda (candidate highest) - (if (and (< candidate number) (> candidate highest)) - candidate - highest)) - 0 - (generation-numbers profile))) + (or (relative-generation profile -1 number) + 0)) (define (generation-file-name profile generation) "Return the file name for PROFILE's GENERATION." @@ -589,4 +604,26 @@ case when generations have been deleted (there are \"holes\")." (make-time time-utc 0 (stat:ctime (stat (generation-file-name profile number))))) +(define (switch-to-generation profile number) + "Atomically switch PROFILE to the generation NUMBER." + (let ((current (generation-number profile)) + (file (generation-file-name profile number))) + (cond ((not (file-exists? profile)) + (format (current-error-port) + (_ "profile '~a' does not exist~%") + profile)) + ((not (file-exists? file)) + (format (current-error-port) + (_ "generation ~a does not exist~%") + number)) + (else + (format #t (_ "switching from generation ~a to ~a~%") + current number) + (switch-symlinks profile file))))) + +(define (switch-to-previous-generation profile) + "Atomically switch PROFILE to the previous generation." + (switch-to-generation profile + (previous-generation-number profile))) + ;;; profiles.scm ends here diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm index fc9c37b..d0f1458 100644 --- a/guix/scripts/package.scm +++ b/guix/scripts/package.scm @@ -94,15 +94,6 @@ return PROFILE unchanged. The goal is to treat '-p ~/.guix-profile' as if (switch-symlinks generation prof))) -(define (switch-to-previous-generation profile) - "Atomically switch PROFILE to the previous generation." - (let* ((number (generation-number profile)) - (previous-number (previous-generation-number profile number)) - (previous-generation (generation-file-name profile previous-number))) - (format #t (_ "switching from generation ~a to ~a~%") - number previous-number) - (switch-symlinks profile previous-generation))) - (define (roll-back store profile) "Roll back to the previous generation of PROFILE." (let* ((number (generation-number profile)) -- 2.1.2 --=-=-= Content-Type: text/x-diff Content-Disposition: attachment; filename=0002-guix-package-Add-switch-generation-option.patch >From 0d89e5466741d8f80a1ac27502cb6cd600afb796 Mon Sep 17 00:00:00 2001 From: Alex Kost Date: Tue, 7 Oct 2014 12:05:06 +0400 Subject: [PATCH 2/2] guix package: Add '--switch-generation' option. * guix/scripts/package.scm: Add '--switch-generation' option. (guix-package): Adjust accordingly. * tests/guix-package.sh: Test it. * doc/guix.texi (Invoking guix package): Document it. --- doc/guix.texi | 15 +++++++++++++++ guix/scripts/package.scm | 35 ++++++++++++++++++++++++++++++----- tests/guix-package.sh | 14 +++++++++++++- 3 files changed, 58 insertions(+), 6 deletions(-) diff --git a/doc/guix.texi b/doc/guix.texi index f6357bd..c6921b1 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -784,6 +784,21 @@ Installing, removing, or upgrading packages from a generation that has been rolled back to overwrites previous future generations. Thus, the history of a profile's generations is always linear. +@item --switch-generation=@var{pattern} +@itemx -S @var{pattern} +Switch to a particular generation defined by @var{pattern}. + +@var{pattern} may be either a generation number or a number prefixed +with ``+'' or ``-''. The latter means: move forward/backward by a +specified number of generations. For example, if you want to return to +the latest generation after @code{--roll-back}, use +@code{--switch-generation=+1}. + +The difference between @code{--roll-back} and +@code{--switch-generation=-1} is that @code{--switch-generation} will +not make a zeroth generation, so if a specified generation does not +exist, the current generation will not be changed. + @item --search-paths @cindex search paths Report environment variable definitions, in Bash syntax, that may be diff --git a/guix/scripts/package.scm b/guix/scripts/package.scm index d0f1458..4a4417e 100644 --- a/guix/scripts/package.scm +++ b/guix/scripts/package.scm @@ -400,6 +400,9 @@ Install, remove, or upgrade PACKAGES in a single transaction.\n")) -d, --delete-generations[=PATTERN] delete generations matching PATTERN")) (display (_ " + -S, --switch-generation=PATTERN + switch to a generation matching PATTERN")) + (display (_ " -p, --profile=PROFILE use PROFILE instead of the user's default profile")) (newline) (display (_ " @@ -479,6 +482,10 @@ Install, remove, or upgrade PACKAGES in a single transaction.\n")) (values (alist-cons 'delete-generations (or arg "") result) #f))) + (option '(#\S "switch-generation") #t #f + (lambda (opt name arg result arg-handler) + (values (alist-cons 'switch-generation arg result) + #f))) (option '("search-paths") #f #f (lambda (opt name arg result arg-handler) (values (cons `(query search-paths) result) @@ -704,13 +711,31 @@ more information.~%")) (generation-number profile)) ;; First roll back if asked to. - (cond ((and (assoc-ref opts 'roll-back?) (not dry-run?)) - (begin - (roll-back (%store) profile) - (process-actions (alist-delete 'roll-back? opts)))) + (cond ((and (assoc-ref opts 'roll-back?) + (not dry-run?)) + (roll-back (%store) profile) + (process-actions (alist-delete 'roll-back? opts))) + ((and (assoc-ref opts 'switch-generation) + (not dry-run?)) + (for-each + (match-lambda + (('switch-generation . pattern) + (let* ((number (string->number pattern)) + (number (and number + (case (string-ref pattern 0) + ((#\+ #\-) + (relative-generation profile number)) + (else number))))) + (if number + (switch-to-generation profile number) + (format (current-error-port) + "Cannot switch to generation '~a'~%" pattern))) + (process-actions (alist-delete 'switch-generation opts))) + (_ #f)) + opts)) ((and (assoc-ref opts 'delete-generations) (not dry-run?)) - (filter-map + (for-each (match-lambda (('delete-generations . pattern) (cond ((not (file-exists? profile)) ; XXX: race condition diff --git a/tests/guix-package.sh b/tests/guix-package.sh index 9b0e75e..5ad0873 100644 --- a/tests/guix-package.sh +++ b/tests/guix-package.sh @@ -100,6 +100,16 @@ then test "`readlink_base "$profile"`" = "$profile-1-link" test -x "$profile/bin/guile" && ! test -x "$profile/bin/make" + # Switch to the rolled generation and switch back. + guix package -p "$profile" --switch-generation=2 + test "`readlink_base "$profile"`" = "$profile-2-link" + guix package -p "$profile" --switch-generation=-1 + test "`readlink_base "$profile"`" = "$profile-1-link" + + # Switching to a non-existing generation does not change the current one. + guix package -p "$profile" --switch-generation=99 + test "`readlink_base "$profile"`" = "$profile-1-link" + # Move to the empty profile. for i in `seq 1 3` do @@ -132,10 +142,12 @@ then grep "`guix build -e "$boot_make"`" "$profile/manifest" # Make a "hole" in the list of generations, and make sure we can - # roll back "over" it. + # roll back and switch "over" it. rm "$profile-1-link" guix package --bootstrap -p "$profile" --roll-back test "`readlink_base "$profile"`" = "$profile-0-link" + guix package -p "$profile" --switch-generation=+1 + test "`readlink_base "$profile"`" = "$profile-2-link" # Make sure LIBRARY_PATH gets listed by `--search-paths'. guix package --bootstrap -p "$profile" -i guile-bootstrap -i gcc-bootstrap -- 2.1.2 --=-=-=--