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shell: Cache profiles even when using package specs.

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This enables profile caching not just when '-m' or '-f' is used, but
also when package specs are passed on the command line, as in:

  guix shell -D guix git

It also changes profile cache keys to include the system type, which was
previously ignored.

* guix/scripts/shell.scm (options-with-caching)[single-file-for-caching]:
Remove.
Call 'profile-cached-gc-root' instead; adjust to accept two values.
(profile-cache-primary-key): New procedure.
(profile-cache-key): Remove.
(profile-file-cache-key, profile-spec-cache-key): New procedures.
(profile-cached-gc-root): Rewrite to include functionality formally in
'single-file-for-caching', but extend to handle package specs.
* gnu/packages.scm (cache-is-authoritative?): Export.
* guix/transformations.scm (transformation-option-key?): New procedure.
* doc/guix.texi (Invoking guix shell): Move '--rebuild-cache'
documentation to the bottom, just above '--root'.  Explain caching and
how these two options relate to that.
This commit is contained in:
Ludovic Courtès 2022-01-05 19:29:50 +01:00
parent 6128c27478
commit 0552dcb294
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GPG key ID: 090B11993D9AEBB5
4 changed files with 142 additions and 76 deletions
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45
doc/guix.texi
View file

@ -5806,17 +5806,6 @@ This is similar to the same-named option in @command{guix package}
(@pxref{profile-manifest, @option{--manifest}}) and uses the same
manifest files.
@item --rebuild-cache
When using @option{--manifest}, @option{--file}, or when invoked without
arguments, @command{guix shell} caches the environment so that
subsequent uses are instantaneous. The cache is invalidated anytime the
file is modified.
The @option{--rebuild-cache} forces the cached environment to be
refreshed even if the file has not changed. This is useful if the
@command{guix.scm} or @command{manifest.scm} has external dependencies,
or if its behavior depends, say, on environment variables.
@item --pure
Unset existing environment variables when building the new environment, except
those specified with @option{--preserve} (see below). This has the effect of
@ -5932,6 +5921,21 @@ directory:
guix shell --container --expose=$HOME=/exchange guile -- guile
@end example
@item --rebuild-cache
@cindex caching, of profiles
@cindex caching, in @command{guix shell}
In most cases, @command{guix shell} caches the environment so that
subsequent uses are instantaneous. Least-recently used cache entries
are periodically removed. The cache is also invalidated, when using
@option{--file} or @option{--manifest}, anytime the corresponding file
is modified.
The @option{--rebuild-cache} forces the cached environment to be
refreshed. This is useful when using @option{--file} or
@option{--manifest} and the @command{guix.scm} or @command{manifest.scm}
file has external dependencies, or if its behavior depends, say, on
environment variables.
@item --root=@var{file}
@itemx -r @var{file}
@cindex persistent environment
@ -5942,11 +5946,20 @@ register it as a garbage collector root.
This is useful if you want to protect your environment from garbage
collection, to make it ``persistent''.
When this option is omitted, the environment is protected from garbage
collection only for the duration of the @command{guix shell}
session. This means that next time you recreate the same environment,
you could have to rebuild or re-download packages. @xref{Invoking guix
gc}, for more on GC roots.
When this option is omitted, @command{guix shell} caches profiles so
that subsequent uses of the same environment are instantaneous---this is
comparable to using @option{--root} except that @command{guix shell}
takes care of periodically removing the least-recently used garbage
collector roots.
In some cases, @command{guix shell} does not cache profiles---e.g., if
transformation options such as @option{--with-latest} are used. In
those cases, the environment is protected from garbage collection only
for the duration of the @command{guix shell} session. This means that
next time you recreate the same environment, you could have to rebuild
or re-download packages.
@xref{Invoking guix gc}, for more on GC roots.
@end table
@command{guix shell} also supports all of the common build options that

3
gnu/packages.scm
View file

@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2012-2020, 2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2014 Eric Bavier <bavier@member.fsf.org>
;;; Copyright © 2016, 2017 Alex Kost <alezost@gmail.com>
@ -51,6 +51,7 @@ (define-module (gnu packages)
%auxiliary-files-path
%package-module-path
%default-package-module-path
cache-is-authoritative?
fold-packages
fold-available-packages

161
guix/scripts/shell.scm
View file

@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2021 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2021-2022 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@ -21,7 +21,8 @@ (define-module (guix scripts shell)
#:use-module ((guix diagnostics) #:select (location))
#:use-module (guix scripts environment)
#:autoload (guix scripts build) (show-build-options-help)
#:autoload (guix transformations) (show-transformation-options-help)
#:autoload (guix transformations) (transformation-option-key?
show-transformation-options-help)
#:use-module (guix scripts)
#:use-module (guix packages)
#:use-module (guix profiles)
@ -40,6 +41,7 @@ (define-module (guix scripts shell)
#:use-module ((guix build utils) #:select (mkdir-p))
#:use-module (guix cache)
#:use-module ((ice-9 ftw) #:select (scandir))
#:autoload (gnu packages) (cache-is-authoritative?)
#:export (guix-shell))
(define (show-help)
@ -201,51 +203,35 @@ (define (authorized-shell-directory? directory)
(const #f)))
(define (options-with-caching opts)
"If OPTS contains exactly one 'load' or one 'manifest' key, automatically
add a 'profile' key (when a profile for that file is already in cache) or a
'gc-root' key (to add the profile to cache)."
(define (single-file-for-caching opts)
(let loop ((opts opts)
(file #f))
(match opts
(() file)
((('package . _) . _) #f)
((('load . ('package candidate)) . rest)
(and (not file) (loop rest candidate)))
((('manifest . candidate) . rest)
(and (not file) (loop rest candidate)))
((('expression . _) . _) #f)
((_ . rest) (loop rest file)))))
;; Check whether there's a single 'load' or 'manifest' option. When that is
;; the case, arrange to automatically cache the resulting profile.
(match (single-file-for-caching opts)
(#f opts)
(file
(let* ((root (profile-cached-gc-root file))
(stat (and root (false-if-exception (lstat root)))))
(if (and (not (assoc-ref opts 'rebuild-cache?))
stat
(<= (stat:mtime ((@ (guile) stat) file))
(stat:mtime stat)))
(let ((now (current-time)))
;; Update the atime on ROOT to reflect usage.
(utime root
now (stat:mtime stat) 0 (stat:mtimensec stat)
AT_SYMLINK_NOFOLLOW)
(alist-cons 'profile root
(remove (match-lambda
(('load . _) #t)
(('manifest . _) #t)
(_ #f))
opts))) ;load right away
(if (and root (not (assq-ref opts 'gc-root)))
(begin
(if stat
(delete-file root)
(mkdir-p (dirname root)))
(alist-cons 'gc-root root opts))
opts))))))
"If OPTS contains only options that allow us to compute a cache key,
automatically add a 'profile' key (when a profile for that file is already in
cache) or a 'gc-root' key (to add the profile to cache)."
;; Attempt to compute a file name for use as the cached profile GC root.
(let* ((root timestamp (profile-cached-gc-root opts))
(stat (and root (false-if-exception (lstat root)))))
(if (and (not (assoc-ref opts 'rebuild-cache?))
stat
(<= timestamp (stat:mtime stat)))
(let ((now (current-time)))
;; Update the atime on ROOT to reflect usage.
(utime root
now (stat:mtime stat) 0 (stat:mtimensec stat)
AT_SYMLINK_NOFOLLOW)
(alist-cons 'profile root
(remove (match-lambda
(('load . _) #t)
(('manifest . _) #t)
(('package . _) #t)
(('ad-hoc-package . _) #t)
(_ #f))
opts))) ;load right away
(if (and root (not (assq-ref opts 'gc-root)))
(begin
(if stat
(delete-file root)
(mkdir-p (dirname root)))
(alist-cons 'gc-root root opts))
opts))))
(define (auto-detect-manifest opts)
"If OPTS do not specify packages or a manifest, load a \"guix.scm\" or
@ -308,28 +294,87 @@ (define %profile-cache-directory
(make-parameter (string-append (cache-directory #:ensure? #f)
"/profiles")))
(define (profile-cache-key file)
(define (profile-cache-primary-key)
"Return the \"primary key\" used when computing keys for the profile cache.
Return #f if no such key can be obtained and caching cannot be
performed--e.g., because the package cache is not authoritative."
(and (cache-is-authoritative?)
(match (current-channels)
(()
#f)
(((= channel-commit commits) ...)
(string-join commits)))))
(define (profile-file-cache-key file system)
"Return the cache key for the profile corresponding to FILE, a 'guix.scm' or
'manifest.scm' file, or #f if we lack channel information."
(match (current-channels)
(() #f)
(((= channel-commit commits) ...)
(match (profile-cache-primary-key)
(#f #f)
(primary-key
(let ((stat (stat file)))
(bytevector->base32-string
;; Since FILE is not canonicalized, only include the device/inode
;; numbers. XXX: In some rare cases involving Btrfs and NFS, this can
;; be insufficient: <https://lwn.net/Articles/866582/>.
(sha256 (string->utf8
(string-append (string-join commits) ":"
(string-append primary-key ":" system ":"
(number->string (stat:dev stat)) ":"
(number->string (stat:ino stat))))))))))
(define (profile-cached-gc-root file)
"Return the cached GC root for FILE, a 'guix.scm' or 'manifest.scm' file, or
#f if we lack information to cache it."
(match (profile-cache-key file)
(#f #f)
(key (string-append (%profile-cache-directory) "/" key))))
(define (profile-spec-cache-key specs system)
"Return the cache key corresponding to SPECS built for SYSTEM, where SPECS
is a list of package specs. Return #f if caching is not possible."
(match (profile-cache-primary-key)
(#f #f)
(primary-key
(bytevector->base32-string
(sha256 (string->utf8
(string-append primary-key ":" system ":"
(object->string specs))))))))
(define (profile-cached-gc-root opts)
"Return two values: the file name of a GC root for use as a profile cache
for the options in OPTS, and a timestamp which, if greater than the GC root's
mtime, indicates that the GC root is stale. If OPTS do not permit caching,
return #f and #f."
(define (key->file key)
(string-append (%profile-cache-directory) "/" key))
(let loop ((opts opts)
(system (%current-system))
(file #f)
(specs '()))
(match opts
(()
(if file
(values (and=> (profile-file-cache-key file system) key->file)
(stat:mtime (stat file)))
(values (and=> (profile-spec-cache-key specs system) key->file)
0)))
(((and spec ('package . _)) . rest)
(if (not file)
(loop rest system file (cons spec specs))
(values #f #f)))
((('load . ('package candidate)) . rest)
(if (and (not file) (null? specs))
(loop rest system candidate specs)
(values #f #f)))
((('manifest . candidate) . rest)
(if (and (not file) (null? specs))
(loop rest system candidate specs)
(values #f #f)))
((('expression . _) . _)
;; Arbitrary expressions might be non-deterministic or otherwise depend
;; on external state so do not cache when they're used.
(values #f #f))
((((? transformation-option-key?) . _) . _)
;; Transformation options are potentially "non-deterministic", or at
;; least depending on external state (with-source, with-commit, etc.),
;; so do not cache anything when they're used.
(values #f #f))
((('system . system) . rest)
(loop rest system file specs))
((_ . rest) (loop rest system file specs)))))
;;;

9
guix/transformations.scm
View file

@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016, 2017, 2018, 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016-2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2021 Marius Bakke <marius@gnu.org>
;;;
;;; This file is part of GNU Guix.
@ -56,6 +56,7 @@ (define-module (guix transformations)
tuned-package
show-transformation-options-help
transformation-option-key?
%transformation-options))
;;; Commentary:
@ -796,6 +797,12 @@ (define (transformation-procedure key)
(and (eq? k key) proc)))
%transformations))
(define (transformation-option-key? key)
"Return true if KEY is an option key (as returned while parsing options with
%TRANSFORMATION-OPTIONS) corresponding to a package transformation option.
For example, (transformation-option-key? 'with-input) => #t."
(->bool (transformation-procedure key)))
;;;
;;; Command-line handling.