guix-kreyren/guix/inferior.scm
Ludovic Courtès 9f371f23eb
inferior: 'cached-channel-instance' does not cache unauthenticated instances.
The comment saying that caching is fine even when AUTHENTICATE? is false
was true in commit 838ac881ec98cb71d4a4e4b20773573f99ecbf25, but it
became incorrect in 7cfd789150f448cf5256b88915bae4163cc9db03, which
no longer calls 'latest-channel-instances' on cache hits.

* guix/inferior.scm (cached-channel-instance): Do not create CACHED when
AUTHENTICATE? is false.
2021-12-01 17:51:33 +01:00

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018, 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
;;;
;;; 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 inferior)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:use-module ((guix diagnostics)
#:select (source-properties->location))
#:use-module ((guix utils)
#:select (%current-system
call-with-temporary-directory
version>? version-prefix?
cache-directory))
#:use-module ((guix store)
#:select (store-connection-socket
store-connection-major-version
store-connection-minor-version
store-lift
&store-protocol-error))
#:use-module ((guix derivations)
#:select (read-derivation-from-file))
#:use-module (guix gexp)
#:use-module (guix search-paths)
#:use-module (guix profiles)
#:use-module (guix channels)
#:use-module ((guix git) #:select (update-cached-checkout))
#:use-module (guix monads)
#:use-module (guix store)
#:use-module (guix derivations)
#:use-module (guix base32)
#:use-module (gcrypt hash)
#:autoload (guix cache) (maybe-remove-expired-cache-entries
file-expiration-time)
#:autoload (guix ui) (build-notifier)
#:autoload (guix build utils) (mkdir-p)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-71)
#:autoload (ice-9 ftw) (scandir)
#:use-module (ice-9 match)
#:use-module (ice-9 popen)
#:use-module (ice-9 vlist)
#:use-module (ice-9 binary-ports)
#:use-module ((rnrs bytevectors) #:select (string->utf8))
#:export (inferior?
open-inferior
port->inferior
close-inferior
inferior-eval
inferior-eval-with-store
inferior-object?
inferior-exception?
inferior-exception-arguments
inferior-exception-inferior
inferior-exception-stack
read-repl-response
inferior-packages
inferior-available-packages
lookup-inferior-packages
inferior-package?
inferior-package-name
inferior-package-version
inferior-package-synopsis
inferior-package-description
inferior-package-home-page
inferior-package-location
inferior-package-inputs
inferior-package-native-inputs
inferior-package-propagated-inputs
inferior-package-transitive-propagated-inputs
inferior-package-native-search-paths
inferior-package-transitive-native-search-paths
inferior-package-search-paths
inferior-package-replacement
inferior-package-provenance
inferior-package-derivation
inferior-package->manifest-entry
gexp->derivation-in-inferior
%inferior-cache-directory
cached-channel-instance
inferior-for-channels))
;;; Commentary:
;;;
;;; This module provides a way to spawn Guix "inferior" processes and to talk
;;; to them. It allows us, from one instance of Guix, to interact with
;;; another instance of Guix coming from a different commit.
;;;
;;; Code:
;; Inferior Guix process.
(define-record-type <inferior>
(inferior pid socket close version packages table)
inferior?
(pid inferior-pid)
(socket inferior-socket)
(close inferior-close-socket) ;procedure
(version inferior-version) ;REPL protocol version
(packages inferior-package-promise) ;promise of inferior packages
(table inferior-package-table)) ;promise of vhash
(define (write-inferior inferior port)
(match inferior
(($ <inferior> pid _ _ version)
(format port "#<inferior ~a ~a ~a>"
pid version
(number->string (object-address inferior) 16)))))
(set-record-type-printer! <inferior> write-inferior)
(define* (inferior-pipe directory command error-port)
"Return an input/output pipe on the Guix instance in DIRECTORY. This runs
'DIRECTORY/COMMAND repl' if it exists, or falls back to some other method if
it's an old Guix."
(let ((pipe (with-error-to-port error-port
(lambda ()
(open-pipe* OPEN_BOTH
(string-append directory "/" command)
"repl" "-t" "machine")))))
(if (eof-object? (peek-char pipe))
(begin
(close-pipe pipe)
;; Older versions of Guix didn't have a 'guix repl' command, so
;; emulate it.
(with-error-to-port error-port
(lambda ()
(open-pipe* OPEN_BOTH "guile"
"-L" (string-append directory "/share/guile/site/"
(effective-version))
"-C" (string-append directory "/share/guile/site/"
(effective-version))
"-C" (string-append directory "/lib/guile/"
(effective-version) "/site-ccache")
"-c"
(object->string
`(begin
(primitive-load ,(search-path %load-path
"guix/repl.scm"))
((@ (guix repl) machine-repl))))))))
pipe)))
(define* (port->inferior pipe #:optional (close close-port))
"Given PIPE, an input/output port, return an inferior that talks over PIPE.
PIPE is closed with CLOSE when 'close-inferior' is called on the returned
inferior."
(setvbuf pipe 'line)
(match (read pipe)
(('repl-version 0 rest ...)
(letrec ((result (inferior 'pipe pipe close (cons 0 rest)
(delay (%inferior-packages result))
(delay (%inferior-package-table result)))))
;; For protocol (0 1) and later, send the protocol version we support.
(match rest
((n _ ...)
(when (>= n 1)
(send-inferior-request '(() repl-version 0 1 1) result)))
(_
#t))
(inferior-eval '(use-modules (guix)) result)
(inferior-eval '(use-modules (gnu)) result)
(inferior-eval '(use-modules (ice-9 match)) result)
(inferior-eval '(use-modules (srfi srfi-34)) result)
(inferior-eval '(define %package-table (make-hash-table))
result)
result))
(_
#f)))
(define* (open-inferior directory
#:key (command "bin/guix")
(error-port (%make-void-port "w")))
"Open the inferior Guix in DIRECTORY, running 'DIRECTORY/COMMAND repl' or
equivalent. Return #f if the inferior could not be launched."
(define pipe
(inferior-pipe directory command error-port))
(port->inferior pipe close-pipe))
(define (close-inferior inferior)
"Close INFERIOR."
(let ((close (inferior-close-socket inferior)))
(close (inferior-socket inferior))))
;; Non-self-quoting object of the inferior.
(define-record-type <inferior-object>
(inferior-object address appearance)
inferior-object?
(address inferior-object-address)
(appearance inferior-object-appearance))
(define (write-inferior-object object port)
(match object
(($ <inferior-object> _ appearance)
(format port "#<inferior-object ~a>" appearance))))
(set-record-type-printer! <inferior-object> write-inferior-object)
;; Reified exception thrown by an inferior.
(define-condition-type &inferior-exception &error
inferior-exception?
(arguments inferior-exception-arguments) ;key + arguments
(inferior inferior-exception-inferior) ;<inferior> | #f
(stack inferior-exception-stack)) ;list of (FILE COLUMN LINE)
(define* (read-repl-response port #:optional inferior)
"Read a (guix repl) response from PORT and return it as a Scheme object.
Raise '&inferior-exception' when an exception is read from PORT."
(define sexp->object
(match-lambda
(('value value)
value)
(('non-self-quoting address string)
(inferior-object address string))))
(match (read port)
(('values objects ...)
(apply values (map sexp->object objects)))
(('exception ('arguments key objects ...)
('stack frames ...))
;; Protocol (0 1 1) and later.
(raise (condition (&inferior-exception
(arguments (cons key (map sexp->object objects)))
(inferior inferior)
(stack frames)))))
(('exception key objects ...)
;; Protocol (0 0).
(raise (condition (&inferior-exception
(arguments (cons key (map sexp->object objects)))
(inferior inferior)
(stack '())))))))
(define (read-inferior-response inferior)
(read-repl-response (inferior-socket inferior)
inferior))
(define (send-inferior-request exp inferior)
(write exp (inferior-socket inferior))
(newline (inferior-socket inferior)))
(define (inferior-eval exp inferior)
"Evaluate EXP in INFERIOR."
(send-inferior-request exp inferior)
(read-inferior-response inferior))
;;;
;;; Inferior packages.
;;;
(define-record-type <inferior-package>
(inferior-package inferior name version id)
inferior-package?
(inferior inferior-package-inferior)
(name inferior-package-name)
(version inferior-package-version)
(id inferior-package-id))
(define (write-inferior-package package port)
(match package
(($ <inferior-package> _ name version)
(format port "#<inferior-package ~a@~a ~a>"
name version
(number->string (object-address package) 16)))))
(set-record-type-printer! <inferior-package> write-inferior-package)
(define (%inferior-packages inferior)
"Compute the list of inferior packages from INFERIOR."
(let ((result (inferior-eval
'(fold-packages (lambda (package result)
(let ((id (object-address package)))
(hashv-set! %package-table id package)
(cons (list (package-name package)
(package-version package)
id)
result)))
'())
inferior)))
(map (match-lambda
((name version id)
(inferior-package inferior name version id)))
result)))
(define (inferior-packages inferior)
"Return the list of packages known to INFERIOR."
(force (inferior-package-promise inferior)))
(define (%inferior-package-table inferior)
"Compute a package lookup table for INFERIOR."
(fold (lambda (package table)
(vhash-cons (inferior-package-name package) package
table))
vlist-null
(inferior-packages inferior)))
(define (inferior-available-packages inferior)
"Return the list of name/version pairs corresponding to the set of packages
available in INFERIOR.
This is faster and less resource-intensive than calling 'inferior-packages'."
(if (inferior-eval '(defined? 'fold-available-packages)
inferior)
(inferior-eval '(fold-available-packages
(lambda* (name version result
#:key supported? deprecated?
#:allow-other-keys)
(if (and supported? (not deprecated?))
(acons name version result)
result))
'())
inferior)
;; As a last resort, if INFERIOR is old and lacks
;; 'fold-available-packages', fall back to 'inferior-packages'.
(map (lambda (package)
(cons (inferior-package-name package)
(inferior-package-version package)))
(inferior-packages inferior))))
(define* (lookup-inferior-packages inferior name #:optional version)
"Return the sorted list of inferior packages matching NAME in INFERIOR, with
highest version numbers first. If VERSION is true, return only packages with
a version number prefixed by VERSION."
;; This is the counterpart of 'find-packages-by-name'.
(sort (filter (lambda (package)
(or (not version)
(version-prefix? version
(inferior-package-version package))))
(vhash-fold* cons '() name
(force (inferior-package-table inferior))))
(lambda (p1 p2)
(version>? (inferior-package-version p1)
(inferior-package-version p2)))))
(define (inferior-package-field package getter)
"Return the field of PACKAGE, an inferior package, accessed with GETTER."
(let ((inferior (inferior-package-inferior package))
(id (inferior-package-id package)))
(inferior-eval `(,getter (hashv-ref %package-table ,id))
inferior)))
(define* (inferior-package-synopsis package #:key (translate? #t))
"Return the Texinfo synopsis of PACKAGE, an inferior package. When
TRANSLATE? is true, translate it to the current locale's language."
(inferior-package-field package
(if translate?
'(compose (@ (guix ui) P_) package-synopsis)
'package-synopsis)))
(define* (inferior-package-description package #:key (translate? #t))
"Return the Texinfo description of PACKAGE, an inferior package. When
TRANSLATE? is true, translate it to the current locale's language."
(inferior-package-field package
(if translate?
'(compose (@ (guix ui) P_) package-description)
'package-description)))
(define (inferior-package-home-page package)
"Return the home page of PACKAGE."
(inferior-package-field package 'package-home-page))
(define (inferior-package-location package)
"Return the source code location of PACKAGE, either #f or a <location>
record."
(source-properties->location
(inferior-package-field package
'(compose (lambda (loc)
(and loc
(location->source-properties
loc)))
package-location))))
(define (inferior-package-input-field package field)
"Return the input field FIELD (e.g., 'native-inputs') of PACKAGE, an
inferior package."
(define field*
`(compose (lambda (inputs)
(map (match-lambda
;; XXX: Origins are not handled.
((label (? package? package) rest ...)
(let ((id (object-address package)))
(hashv-set! %package-table id package)
`(,label (package ,id
,(package-name package)
,(package-version package))
,@rest)))
(x
x))
inputs))
,field))
(define inputs
(inferior-package-field package field*))
(define inferior
(inferior-package-inferior package))
(map (match-lambda
((label ('package id name version) . rest)
;; XXX: eq?-ness of inferior packages is not preserved here.
`(,label ,(inferior-package inferior name version id)
,@rest))
(x x))
inputs))
(define inferior-package-inputs
(cut inferior-package-input-field <> 'package-inputs))
(define inferior-package-native-inputs
(cut inferior-package-input-field <> 'package-native-inputs))
(define inferior-package-propagated-inputs
(cut inferior-package-input-field <> 'package-propagated-inputs))
(define inferior-package-transitive-propagated-inputs
(cut inferior-package-input-field <> 'package-transitive-propagated-inputs))
(define (%inferior-package-search-paths package field)
"Return the list of search path specifications of PACKAGE, an inferior
package."
(define paths
(inferior-package-field package
`(compose (lambda (paths)
(map (@ (guix search-paths)
search-path-specification->sexp)
paths))
,field)))
(map sexp->search-path-specification paths))
(define inferior-package-native-search-paths
(cut %inferior-package-search-paths <> 'package-native-search-paths))
(define inferior-package-search-paths
(cut %inferior-package-search-paths <> 'package-search-paths))
(define inferior-package-transitive-native-search-paths
(cut %inferior-package-search-paths <> 'package-transitive-native-search-paths))
(define (inferior-package-replacement package)
"Return the replacement for PACKAGE. This will either be an inferior
package, or #f."
(match (inferior-package-field
package
'(compose (match-lambda
((? package? package)
(let ((id (object-address package)))
(hashv-set! %package-table id package)
(list id
(package-name package)
(package-version package))))
(#f #f))
package-replacement))
(#f #f)
((id name version)
(inferior-package (inferior-package-inferior package)
name
version
id))))
(define (inferior-package-provenance package)
"Return a \"provenance sexp\" for PACKAGE, an inferior package. The result
is similar to the sexp returned by 'package-provenance' for regular packages."
(inferior-package-field package
'(let* ((describe
(false-if-exception
(resolve-interface '(guix describe))))
(provenance
(false-if-exception
(module-ref describe
'package-provenance))))
(or provenance (const #f)))))
(define (proxy client backend) ;adapted from (guix ssh)
"Proxy communication between CLIENT and BACKEND until CLIENT closes the
connection, at which point CLIENT is closed (both CLIENT and BACKEND must be
input/output ports.)"
;; Use buffered ports so that 'get-bytevector-some' returns up to the
;; whole buffer like read(2) would--see <https://bugs.gnu.org/30066>.
(setvbuf client 'block 65536)
(setvbuf backend 'block 65536)
(let loop ()
(match (select (list client backend) '() '())
((reads () ())
(when (memq client reads)
(match (get-bytevector-some client)
((? eof-object?)
(close-port client))
(bv
(put-bytevector backend bv)
(force-output backend))))
(when (memq backend reads)
(match (get-bytevector-some backend)
(bv
(put-bytevector client bv)
(force-output client))))
(unless (port-closed? client)
(loop))))))
(define (inferior-eval-with-store inferior store code)
"Evaluate CODE in INFERIOR, passing it STORE as its argument. CODE must
thus be the code of a one-argument procedure that accepts a store."
;; Create a named socket in /tmp and let INFERIOR connect to it and use it
;; as its store. This ensures the inferior uses the same store, with the
;; same options, the same per-session GC roots, etc.
;; FIXME: This strategy doesn't work for remote inferiors (SSH).
(call-with-temporary-directory
(lambda (directory)
(chmod directory #o700)
(let* ((name (string-append directory "/inferior"))
(socket (socket AF_UNIX SOCK_STREAM 0))
(major (store-connection-major-version store))
(minor (store-connection-minor-version store))
(proto (logior major minor)))
(bind socket AF_UNIX name)
(listen socket 1024)
(send-inferior-request
`(let ((proc ,code)
(socket (socket AF_UNIX SOCK_STREAM 0))
(error? (if (defined? 'store-protocol-error?)
store-protocol-error?
nix-protocol-error?))
(error-message (if (defined? 'store-protocol-error-message)
store-protocol-error-message
nix-protocol-error-message)))
(connect socket AF_UNIX ,name)
;; 'port->connection' appeared in June 2018 and we can hardly
;; emulate it on older versions. Thus fall back to
;; 'open-connection', at the risk of talking to the wrong daemon or
;; having our build result reclaimed (XXX).
(let ((store (if (defined? 'port->connection)
(port->connection socket #:version ,proto)
(open-connection))))
(dynamic-wind
(const #t)
(lambda ()
;; Serialize '&store-protocol-error' conditions. The
;; exception serialization mechanism that
;; 'read-repl-response' expects is unsuitable for SRFI-35
;; error conditions, hence this special case.
(guard (c ((error? c)
`(store-protocol-error ,(error-message c))))
`(result ,(proc store))))
(lambda ()
(close-connection store)
(close-port socket)))))
inferior)
(match (accept socket)
((client . address)
(proxy client (store-connection-socket store))))
(close-port socket)
(match (read-inferior-response inferior)
(('store-protocol-error message)
(raise (condition
(&store-protocol-error (message message)
(status 1)))))
(('result result)
result))))))
(define* (inferior-package-derivation store package
#:optional
(system (%current-system))
#:key target)
"Return the derivation for PACKAGE, an inferior package, built for SYSTEM
and cross-built for TARGET if TARGET is true. The inferior corresponding to
PACKAGE must be live."
(define proc
`(lambda (store)
(let* ((package (hashv-ref %package-table
,(inferior-package-id package)))
(drv ,(if target
`(package-cross-derivation store package
,target
,system)
`(package-derivation store package
,system))))
(derivation-file-name drv))))
(and=> (inferior-eval-with-store (inferior-package-inferior package) store
proc)
read-derivation-from-file))
(define inferior-package->derivation
(store-lift inferior-package-derivation))
(define-gexp-compiler (package-compiler (package <inferior-package>) system
target)
;; Compile PACKAGE for SYSTEM, optionally cross-building for TARGET.
(inferior-package->derivation package system #:target target))
(define* (gexp->derivation-in-inferior name exp guix
#:key silent-failure?
#:allow-other-keys
#:rest rest)
"Return a derivation that evaluates EXP with GUIX, an instance of Guix as
returned for example by 'channel-instances->derivation'. Other arguments are
passed as-is to 'gexp->derivation'.
When SILENT-FAILURE? is true, create an empty output directory instead of
failing when GUIX is too old and lacks the 'guix repl' command."
(define script
;; EXP wrapped with a proper (set! %load-path …) prologue.
(scheme-file "inferior-script.scm" exp))
(define trampoline
;; This is a crude way to run EXP on GUIX. TODO: use 'raw-derivation' and
;; make 'guix repl' the "builder"; this will require "opening up" the
;; mechanisms behind 'gexp->derivation', and adding '-l' to 'guix repl'.
#~(begin
(use-modules (ice-9 popen))
(let ((pipe (open-pipe* OPEN_WRITE
#+(file-append guix "/bin/guix")
"repl" "-t" "machine")))
;; XXX: EXP presumably refers to #$output but that reference is lost
;; so explicitly reference it here.
#$output
(write `(primitive-load #$script) pipe)
(unless (zero? (close-pipe pipe))
(if #$silent-failure?
(mkdir #$output)
(error "inferior failed" #+guix))))))
(define (drop-extra-keyword lst)
(let loop ((lst lst)
(result '()))
(match lst
(()
(reverse result))
((#:silent-failure? _ . rest)
(loop rest result))
((kw value . tail)
(loop tail (cons* value kw result))))))
(apply gexp->derivation name trampoline
(drop-extra-keyword rest)))
;;;
;;; Manifest entries.
;;;
(define* (inferior-package->manifest-entry package
#:optional (output "out")
#:key (properties '()))
"Return a manifest entry for the OUTPUT of package PACKAGE."
(define cache
(make-hash-table))
(define-syntax-rule (memoized package output exp)
;; Memoize the entry returned by EXP for PACKAGE/OUTPUT. This is
;; important as the same package may be traversed many times through
;; propagated inputs, and querying the inferior is costly. Use
;; 'hash'/'equal?', which is okay since <inferior-package> is simple.
(let ((compute (lambda () exp))
(key (cons package output)))
(or (hash-ref cache key)
(let ((result (compute)))
(hash-set! cache key result)
result))))
(let loop ((package package)
(output output)
(parent (delay #f)))
(memoized package output
;; For each dependency, keep a promise pointing to its "parent" entry.
(letrec* ((deps (map (match-lambda
((label package)
(loop package "out" (delay entry)))
((label package output)
(loop package output (delay entry))))
(inferior-package-propagated-inputs package)))
(entry (manifest-entry
(name (inferior-package-name package))
(version (inferior-package-version package))
(output output)
(item package)
(dependencies (delete-duplicates deps))
(search-paths
(inferior-package-transitive-native-search-paths package))
(parent parent)
(properties properties))))
entry))))
;;;
;;; Cached inferiors.
;;;
(define %inferior-cache-directory
;; Directory for cached inferiors (GC roots).
(make-parameter (string-append (cache-directory #:ensure? #f)
"/inferiors")))
(define (channel-full-commit channel)
"Return the commit designated by CHANNEL as quickly as possible. If
CHANNEL's 'commit' field is a full SHA1, return it as-is; if it's a SHA1
prefix, resolve it; and if 'commit' is unset, fetch CHANNEL's branch tip."
(let ((commit (channel-commit channel))
(branch (channel-branch channel)))
(if (and commit (= (string-length commit) 40))
commit
(let* ((ref (if commit `(commit . ,commit) `(branch . ,branch)))
(cache commit relation
(update-cached-checkout (channel-url channel)
#:ref ref
#:check-out? #f)))
commit))))
(define* (cached-channel-instance store
channels
#:key
(authenticate? #t)
(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. AUTHENTICATE?
determines whether CHANNELS are authenticated."
(define commits
;; Since computing the instances of CHANNELS is I/O-intensive, use a
;; cheaper way to get the commit list of CHANNELS. This limits overhead
;; to the minimum in case of a cache hit.
(map channel-full-commit channels))
(define key
(bytevector->base32-string
(sha256
(string->utf8 (string-concatenate commits)))))
(define cached
(string-append cache-directory "/" key))
(define (base32-encoded-sha256? str)
(= (string-length str) 52))
(define (cache-entries directory)
(map (lambda (file)
(string-append directory "/" file))
(scandir directory base32-encoded-sha256?)))
(define (symlink/safe old new)
(catch 'system-error
(lambda ()
(symlink old new))
(lambda args
(unless (= EEXIST (system-error-errno args))
(apply throw args)))))
(define symlink*
(lift2 symlink/safe %store-monad))
(define add-indirect-root*
(store-lift add-indirect-root))
(define add-temp-root*
(store-lift add-temp-root))
(mkdir-p cache-directory)
(maybe-remove-expired-cache-entries cache-directory
cache-entries
#:entry-expiration
(file-expiration-time ttl))
(if (file-exists? cached)
cached
(run-with-store store
(mlet* %store-monad ((instances
-> (latest-channel-instances store channels
#:authenticate?
authenticate?))
(profile
(channel-instances->derivation instances)))
(mbegin %store-monad
;; It's up to the caller to install a build handler to report
;; what's going to be built.
(built-derivations (list profile))
;; Cache if and only if AUTHENTICATE? is true.
(if authenticate?
(mbegin %store-monad
(symlink* (derivation->output-path profile) cached)
(add-indirect-root* cached)
(return cached))
(mbegin %store-monad
(add-temp-root* profile)
(return profile))))))))
(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
(with-store store
;; XXX: Install a build notifier out of convenience, so users know
;; what's going on. However, we cannot be sure that its options, such
;; as #:use-substitutes?, correspond to the daemon's default settings.
(with-build-handler (build-notifier)
(cached-channel-instance store
channels
#:cache-directory cache-directory
#:ttl ttl))))
(open-inferior cached))
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