diff --git a/Makefile.am b/Makefile.am index b1f33946c5..b3f03d44c8 100644 --- a/Makefile.am +++ b/Makefile.am @@ -278,6 +278,7 @@ MODULES = \ guix/scripts/container.scm \ guix/scripts/container/exec.scm \ guix/scripts/deploy.scm \ + guix/scripts/time-machine.scm \ guix.scm \ $(GNU_SYSTEM_MODULES) diff --git a/doc/guix.texi b/doc/guix.texi index ed88778016..bc1d5d863a 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -198,6 +198,7 @@ Package Management * Invoking guix gc:: Running the garbage collector. * Invoking guix pull:: Fetching the latest Guix and distribution. * Channels:: Customizing the package collection. +* Invoking guix time-machine:: Running an older revision of Guix. * Inferiors:: Interacting with another revision of Guix. * Invoking guix describe:: Display information about your Guix revision. * Invoking guix archive:: Exporting and importing store files. @@ -2550,6 +2551,7 @@ guix install emacs-guix * Invoking guix gc:: Running the garbage collector. * Invoking guix pull:: Fetching the latest Guix and distribution. * Channels:: Customizing the package collection. +* Invoking guix time-machine:: Running an older revision of Guix. * Inferiors:: Interacting with another revision of Guix. * Invoking guix describe:: Display information about your Guix revision. * Invoking guix archive:: Exporting and importing store files. @@ -4152,7 +4154,10 @@ say, on another machine, by providing a channel specification in @end lisp The @command{guix describe --format=channels} command can even generate this -list of channels directly (@pxref{Invoking guix describe}). +list of channels directly (@pxref{Invoking guix describe}). The resulting +file can be used with the -C options of @command{guix pull} +(@pxref{Invoking guix pull}) or @command{guix time-machine} +(@pxref{Invoking guix time-machine}). At this point the two machines run the @emph{exact same Guix}, with access to the @emph{exact same packages}. The output of @command{guix build gimp} on @@ -4166,6 +4171,57 @@ artifacts with very fine grain, and to reproduce software environments at will---some sort of ``meta reproducibility'' capabilities, if you will. @xref{Inferiors}, for another way to take advantage of these super powers. +@node Invoking guix time-machine +@section Invoking @command{guix time-machine} + +@cindex @command{guix time-machine} +@cindex pinning, channels +@cindex replicating Guix +@cindex reproducibility, of Guix + +The @command{guix time-machine} command provides access to other +revisions of Guix, for example to install older versions of packages, +or to reproduce a computation in an identical environment. The revision +of Guix to be used is defined by a commit or by a channel +description file created by @command{guix describe} +(@pxref{Invoking guix describe}). + +The general syntax is: + +@example +guix time-machine @var{options}@dots{} -- @var{command} @var {arg}@dots{} +@end example + +where @var{command} and @var{arg}@dots{} are passed unmodified to the +@command{guix} command if the specified revision. The @var{options} that define +this revision are the same as for @command{guix pull} (@pxref{Invoking guix pull}): + +@table @code +@item --url=@var{url} +@itemx --commit=@var{commit} +@itemx --branch=@var{branch} +Use the @code{guix} channel from the specified @var{url}, at the +given @var{commit} (a valid Git commit ID represented as a hexadecimal +string), or @var{branch}. + +@item --channels=@var{file} +@itemx -C @var{file} +Read the list of channels from @var{file}. @var{file} must contain +Scheme code that evaluates to a list of channel objects. +@xref{Channels} for more information. +@end table + +As for @command{guix pull}, the absence of any options means that the +the latest commit on the master branch will be used. The command + +@example +guix time-machine -- build hello +@end example + +will thus build the package @code{hello} as defined in the master branch, +which is in general a newer revison of Guix than you have installed. +Time travel works in both directions! + @node Inferiors @section Inferiors @@ -10589,7 +10645,6 @@ ClientPID: 19419 ClientCommand: cuirass --cache-directory /var/cache/cuirass @dots{} @end example - @node System Configuration @chapter System Configuration diff --git a/guix/inferior.scm b/guix/inferior.scm index b8e2f21f42..be50e0ec26 100644 --- a/guix/inferior.scm +++ b/guix/inferior.scm @@ -89,6 +89,7 @@ (define-module (guix inferior) gexp->derivation-in-inferior %inferior-cache-directory + cached-channel-instance inferior-for-channels)) ;;; Commentary: @@ -635,16 +636,13 @@ (define %inferior-cache-directory (make-parameter (string-append (cache-directory #:ensure? #f) "/inferiors"))) -(define* (inferior-for-channels channels - #:key - (cache-directory (%inferior-cache-directory)) - (ttl (* 3600 24 30))) - "Return an inferior for CHANNELS, a list of channels. Use the cache at -CACHE-DIRECTORY, where entries can be reclaimed after TTL seconds. This -procedure opens a new connection to the build daemon. - -This is a convenience procedure that people may use in manifests passed to -'guix package -m', for instance." +(define* (cached-channel-instance channels + #:key + (cache-directory (%inferior-cache-directory)) + (ttl (* 3600 24 30))) + "Return a directory containing a guix filetree defined by CHANNELS, a list of channels. +The directory is a subdirectory of CACHE-DIRECTORY, where entries can be reclaimed after TTL seconds. +This procedure opens a new connection to the build daemon." (with-store store (let () (define instances @@ -680,7 +678,7 @@ (define add-indirect-root* (file-expiration-time ttl)) (if (file-exists? cached) - (open-inferior cached) + cached (run-with-store store (mlet %store-monad ((profile (channel-instances->derivation instances))) @@ -689,4 +687,20 @@ (define add-indirect-root* (built-derivations (list profile)) (symlink* (derivation->output-path profile) cached) (add-indirect-root* cached) - (return (open-inferior cached))))))))) + (return cached)))))))) + +(define* (inferior-for-channels channels + #:key + (cache-directory (%inferior-cache-directory)) + (ttl (* 3600 24 30))) + "Return an inferior for CHANNELS, a list of channels. Use the cache at +CACHE-DIRECTORY, where entries can be reclaimed after TTL seconds. This +procedure opens a new connection to the build daemon. + +This is a convenience procedure that people may use in manifests passed to +'guix package -m', for instance." + (define cached + (cached-channel-instance channels + #:cache-directory cache-directory + #:ttl ttl)) + (open-inferior cached)) diff --git a/guix/scripts/pull.scm b/guix/scripts/pull.scm index 418998409a..c42794dbcb 100644 --- a/guix/scripts/pull.scm +++ b/guix/scripts/pull.scm @@ -56,6 +56,7 @@ (define-module (guix scripts pull) #:use-module (ice-9 vlist) #:use-module (ice-9 format) #:export (display-profile-content + channel-list guix-pull)) diff --git a/guix/scripts/time-machine.scm b/guix/scripts/time-machine.scm new file mode 100644 index 0000000000..a6598fb0f7 --- /dev/null +++ b/guix/scripts/time-machine.scm @@ -0,0 +1,102 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2019 Konrad Hinsen +;;; +;;; 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 the GNU General Public License +;;; along with GNU Guix. If not, see . + +(define-module (guix scripts time-machine) + #:use-module (guix ui) + #:use-module (guix scripts) + #:use-module (guix inferior) + #:use-module (guix channels) + #:use-module ((guix scripts pull) #:select (channel-list)) + #:use-module (ice-9 match) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-11) + #:use-module (srfi srfi-26) + #:use-module (srfi srfi-37) + #:export (guix-time-machine)) + + +;;; +;;; Command-line options. +;;; + +(define (show-help) + (display (G_ "Usage: guix time-machine [OPTION] -- COMMAND ARGS... +Execute COMMAND ARGS... in an older version of Guix.\n")) + (display (G_ " + -C, --channels=FILE deploy the channels defined in FILE")) + (display (G_ " + --url=URL use the Git repository at URL")) + (display (G_ " + --commit=COMMIT use the specified COMMIT")) + (display (G_ " + --branch=BRANCH use the tip of the specified BRANCH")) + (display (G_ " + -h, --help display this help and exit")) + (display (G_ " + -V, --version display version information and exit")) + (newline) + (show-bug-report-information)) + +(define %options + ;; Specifications of the command-line options. + (list (option '(#\C "channels") #t #f + (lambda (opt name arg result) + (alist-cons 'channel-file arg result))) + (option '("url") #t #f + (lambda (opt name arg result) + (alist-cons 'repository-url arg + (alist-delete 'repository-url result)))) + (option '("commit") #t #f + (lambda (opt name arg result) + (alist-cons 'ref `(commit . ,arg) result))) + (option '("branch") #t #f + (lambda (opt name arg result) + (alist-cons 'ref `(branch . ,arg) result))) + (option '(#\h "help") #f #f + (lambda args + (show-help) + (exit 0))) + (option '(#\V "version") #f #f + (lambda args + (show-version-and-exit "guix time-machine"))))) + +(define (parse-args args) + "Parse the list of command line arguments ARGS." + ;; The '--' token is used to separate the command to run from the rest of + ;; the operands. + (let-values (((args command) (break (cut string=? "--" <>) args))) + (let ((opts (parse-command-line args %options '(()) #:build-options? #f))) + (match command + (() opts) + (("--") opts) + (("--" command ...) (alist-cons 'exec command opts)))))) + + +;;; +;;; Entry point. +;;; + +(define (guix-time-machine . args) + (with-error-handling + (let* ((opts (parse-args args)) + (channels (channel-list opts)) + (command-line (assoc-ref opts 'exec))) + (when command-line + (let* ((directory (cached-channel-instance channels)) + (executable (string-append directory "/bin/guix"))) + (apply execl (cons* executable executable command-line)))))))