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authorKonrad Hinsen <konrad.hinsen@fastmail.net>2019-10-25 17:42:21 +0200
committerLudovic Courtès <ludo@gnu.org>2019-11-15 23:28:17 +0100
commitf675f8dec73d02e319e607559ed2316c299ae8c7 (patch)
treeb8188a70e7cfc211b40a3406aeefd185b129b64c
parent1edcfda81ba5c20ca715473d45315662c60dd81e (diff)
downloadguix-f675f8dec73d02e319e607559ed2316c299ae8c7.tar
guix-f675f8dec73d02e319e607559ed2316c299ae8c7.tar.gz
Add 'guix time-machine'.
* guix/scripts/time-machine.scm: New file. * Makefile.am: (MODULES): Add it. * guix/scripts/pull.scm (channel-list): Export. * guix/inferior.scm (cached-channel-instance): New procedure. (inferior-for-channels): Use it. * doc/guix.texi (Invoking guix time-machine): New section. (Channels): Cross-reference it. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
-rw-r--r--Makefile.am1
-rw-r--r--doc/guix.texi59
-rw-r--r--guix/inferior.scm38
-rw-r--r--guix/scripts/pull.scm1
-rw-r--r--guix/scripts/time-machine.scm102
5 files changed, 187 insertions, 14 deletions
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 @@
gexp->derivation-in-inferior
%inferior-cache-directory
+ cached-channel-instance
inferior-for-channels))
;;; Commentary:
@@ -635,16 +636,13 @@ failing when GUIX is too old and lacks the 'guix repl' command."
(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 @@ This is a convenience procedure that people may use in manifests passed to
(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 @@ This is a convenience procedure that people may use in manifests passed to
(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 @@
#: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 <konrad.hinsen@fastmail.net>
+;;;
+;;; 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 <http://www.gnu.org/licenses/>.
+
+(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)))))))