guix-play/guix/channels.scm
Ricardo Wurmus af12790bdd
guix: Add support for channel dependencies.
* guix/channels.scm (<channel-metadata>): New record.
(read-channel-metadata, channel-instance-dependencies): New procedures.
(latest-channel-instances): Include channel dependencies; add optional
argument PREVIOUS-CHANNELS.
(channel-instance-derivations): Build derivation for additional channels and
add it as dependency to the channel instance derivation.
* doc/guix.texi (Channels): Add subsection "Declaring Channel Dependencies".
* tests/channels.scm: New file.
* Makefile.am (SCM_TESTS): Add it.
2018-12-09 13:55:22 +01:00

413 lines
18 KiB
Scheme

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.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 channels)
#:use-module (guix git)
#:use-module (guix records)
#:use-module (guix gexp)
#:use-module (guix discovery)
#:use-module (guix monads)
#:use-module (guix profiles)
#:use-module (guix derivations)
#:use-module (guix store)
#:use-module (guix i18n)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-2)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-11)
#:autoload (guix self) (whole-package)
#:use-module (ice-9 match)
#:export (channel
channel?
channel-name
channel-url
channel-branch
channel-commit
channel-location
%default-channels
channel-instance?
channel-instance-channel
channel-instance-commit
channel-instance-checkout
latest-channel-instances
checkout->channel-instance
latest-channel-derivation
channel-instances->manifest
channel-instances->derivation))
;;; Commentary:
;;;
;;; This module implements "channels." A channel is usually a source of
;;; package definitions. There's a special channel, the 'guix' channel, that
;;; provides all of Guix, including its commands and its documentation.
;;; User-defined channels are expected to typically provide a bunch of .scm
;;; files meant to be added to the '%package-search-path'.
;;;
;;; This module provides tools to fetch and update channels from a Git
;;; repository and to build them.
;;;
;;; Code:
(define-record-type* <channel> channel make-channel
channel?
(name channel-name)
(url channel-url)
(branch channel-branch (default "master"))
(commit channel-commit (default #f))
(location channel-location
(default (current-source-location)) (innate)))
(define %default-channels
;; Default list of channels.
(list (channel
(name 'guix)
(branch "master")
(url "https://git.savannah.gnu.org/git/guix.git"))))
(define (guix-channel? channel)
"Return true if CHANNEL is the 'guix' channel."
(eq? 'guix (channel-name channel)))
(define-record-type <channel-instance>
(channel-instance channel commit checkout)
channel-instance?
(channel channel-instance-channel)
(commit channel-instance-commit)
(checkout channel-instance-checkout))
(define-record-type <channel-metadata>
(channel-metadata version dependencies)
channel-metadata?
(version channel-metadata-version)
(dependencies channel-metadata-dependencies))
(define (channel-reference channel)
"Return the \"reference\" for CHANNEL, an sexp suitable for
'latest-repository-commit'."
(match (channel-commit channel)
(#f `(branch . ,(channel-branch channel)))
(commit `(commit . ,(channel-commit channel)))))
(define (read-channel-metadata instance)
"Return a channel-metadata record read from the channel INSTANCE's
description file, or return #F if the channel instance does not include the
file."
(let* ((source (channel-instance-checkout instance))
(meta-file (string-append source "/.guix-channel")))
(and (file-exists? meta-file)
(and-let* ((raw (call-with-input-file meta-file read))
(version (and=> (assoc-ref raw 'version) first))
(dependencies (or (assoc-ref raw 'dependencies) '())))
(channel-metadata
version
(map (lambda (item)
(let ((get (lambda* (key #:optional default)
(or (and=> (assoc-ref item key) first) default))))
(and-let* ((name (get 'name))
(url (get 'url))
(branch (get 'branch "master")))
(channel
(name name)
(branch branch)
(url url)
(commit (get 'commit))))))
dependencies))))))
(define (channel-instance-dependencies instance)
"Return the list of channels that are declared as dependencies for the given
channel INSTANCE."
(match (read-channel-metadata instance)
(#f '())
(($ <channel-metadata> version dependencies)
dependencies)))
(define* (latest-channel-instances store channels #:optional (previous-channels '()))
"Return a list of channel instances corresponding to the latest checkouts of
CHANNELS and the channels on which they depend. PREVIOUS-CHANNELS is a list
of previously processed channels."
;; Only process channels that are unique, or that are more specific than a
;; previous channel specification.
(define (ignore? channel others)
(member channel others
(lambda (a b)
(and (eq? (channel-name a) (channel-name b))
(or (channel-commit b)
(not (or (channel-commit a)
(channel-commit b))))))))
;; Accumulate a list of instances. A list of processed channels is also
;; accumulated to decide on duplicate channel specifications.
(match (fold (lambda (channel acc)
(match acc
((#:channels previous-channels #:instances instances)
(if (ignore? channel previous-channels)
acc
(begin
(format (current-error-port)
(G_ "Updating channel '~a' from Git repository at '~a'...~%")
(channel-name channel)
(channel-url channel))
(let-values (((checkout commit)
(latest-repository-commit store (channel-url channel)
#:ref (channel-reference
channel))))
(let ((instance (channel-instance channel commit checkout)))
(let-values (((new-instances new-channels)
(latest-channel-instances
store
(channel-instance-dependencies instance)
previous-channels)))
`(#:channels
,(append (cons channel new-channels)
previous-channels)
#:instances
,(append (cons instance new-instances)
instances))))))))))
`(#:channels ,previous-channels #:instances ())
channels)
((#:channels channels #:instances instances)
(let ((instance-name (compose channel-name channel-instance-channel)))
;; Remove all earlier channel specifications if they are followed by a
;; more specific one.
(values (delete-duplicates instances
(lambda (a b)
(eq? (instance-name a) (instance-name b))))
channels)))))
(define* (checkout->channel-instance checkout
#:key commit
(url checkout) (name 'guix))
"Return a channel instance for CHECKOUT, which is assumed to be a checkout
of COMMIT at URL. Use NAME as the channel name."
(let* ((commit (or commit (make-string 40 #\0)))
(channel (channel (name name)
(commit commit)
(url url))))
(channel-instance channel commit checkout)))
(define %self-build-file
;; The file containing code to build Guix. This serves the same purpose as
;; a makefile, and, similarly, is intended to always keep this name.
"build-aux/build-self.scm")
(define %pull-version
;; This is the version of the 'guix pull' protocol. It specifies what's
;; expected from %SELF-BUILD-FILE. The initial version ("0") was when we'd
;; place a set of compiled Guile modules in ~/.config/guix/latest.
1)
(define (standard-module-derivation name source dependencies)
"Return a derivation that builds the Scheme modules in SOURCE and that
depend on DEPENDENCIES, a list of lowerable objects. The assumption is that
SOURCE contains package modules to be added to '%package-module-path'."
(define modules
(scheme-modules* source))
;; FIXME: We should load, say SOURCE/.guix-channel.scm, which would allow
;; channel publishers to specify things such as the sub-directory where .scm
;; files live, files to exclude from the channel, preferred substitute URLs,
;; etc.
(mlet* %store-monad ((compiled
(compiled-modules modules
#:name name
#:module-path (list source)
#:extensions dependencies)))
(gexp->derivation name
(with-extensions dependencies
(with-imported-modules '((guix build utils))
#~(begin
(use-modules (guix build utils))
(let ((go (string-append #$output "/lib/guile/"
(effective-version)
"/site-ccache"))
(scm (string-append #$output
"/share/guile/site/"
(effective-version))))
(mkdir-p (dirname go))
(symlink #$compiled go)
(mkdir-p (dirname scm))
(symlink #$source scm))))))))
(define* (build-from-source name source
#:key verbose? commit
(dependencies '()))
"Return a derivation to build Guix from SOURCE, using the self-build script
contained therein. Use COMMIT as the version string."
;; Running the self-build script makes it easier to update the build
;; procedure: the self-build script of the Guix-to-be-installed contains the
;; right dependencies, build procedure, etc., which the Guix-in-use may not
;; be know.
(define script
(string-append source "/" %self-build-file))
(if (file-exists? script)
(let ((build (save-module-excursion
(lambda ()
(primitive-load script)))))
;; BUILD must be a monadic procedure of at least one argument: the
;; source tree.
;;
;; Note: BUILD can return #f if it does not support %PULL-VERSION. In
;; the future we'll fall back to a previous version of the protocol
;; when that happens.
(build source #:verbose? verbose? #:version commit
#:pull-version %pull-version))
;; Build a set of modules that extend Guix using the standard method.
(standard-module-derivation name source dependencies)))
(define* (build-channel-instance instance #:optional (dependencies '()))
"Return, as a monadic value, the derivation for INSTANCE, a channel
instance. DEPENDENCIES is a list of extensions providing Guile modules that
INSTANCE depends on."
(build-from-source (symbol->string
(channel-name (channel-instance-channel instance)))
(channel-instance-checkout instance)
#:commit (channel-instance-commit instance)
#:dependencies dependencies))
(define (channel-instance-derivations instances)
"Return the list of derivations to build INSTANCES, in the same order as
INSTANCES."
(define core-instance
;; The 'guix' channel is treated specially: it's an implicit dependency of
;; all the other channels.
(find (lambda (instance)
(guix-channel? (channel-instance-channel instance)))
instances))
(define dependencies
;; Dependencies of CORE-INSTANCE.
;; FIXME: It would be best not to hard-wire this information here and
;; instead query it to CORE-INSTANCE.
(list (module-ref (resolve-interface '(gnu packages gnupg))
'guile-gcrypt)
(module-ref (resolve-interface '(gnu packages guile))
'guile-git)
(module-ref (resolve-interface '(gnu packages guile))
'guile-bytestructures)))
(mlet %store-monad ((core (build-channel-instance core-instance)))
(mapm %store-monad
(lambda (instance)
(if (eq? instance core-instance)
(return core)
(match (channel-instance-dependencies instance)
(()
(build-channel-instance instance
(cons core dependencies)))
(channels
(mlet %store-monad ((dependencies-derivation
(latest-channel-derivation
;; %default-channels is used here to
;; ensure that the core channel is
;; available for channels declared as
;; dependencies.
(append channels %default-channels))))
(build-channel-instance instance
(cons dependencies-derivation
(cons core dependencies))))))))
instances)))
(define (whole-package-for-legacy name modules)
"Return a full-blown Guix package for MODULES, a derivation that builds Guix
modules in the old ~/.config/guix/latest style."
(define packages
(resolve-interface '(gnu packages guile)))
(letrec-syntax ((list (syntax-rules (->)
((_)
'())
((_ (module -> variable) rest ...)
(cons (module-ref (resolve-interface
'(gnu packages module))
'variable)
(list rest ...)))
((_ variable rest ...)
(cons (module-ref packages 'variable)
(list rest ...))))))
(whole-package name modules
;; In the "old style", %SELF-BUILD-FILE would simply return a
;; derivation that builds modules. We have to infer what the
;; dependencies of these modules were.
(list guile-json guile-git guile-bytestructures
(ssh -> guile-ssh) (tls -> gnutls)))))
(define (old-style-guix? drv)
"Return true if DRV corresponds to a ~/.config/guix/latest style of
derivation."
;; Here we rely on a gross historical fact: that derivations produced by the
;; "old style" (before commit 8a0d9bc8a3f153159d9e239a151c0fa98f1e12d8,
;; dated May 30, 2018) did not depend on "guix-command.drv".
(not (find (lambda (input)
(string-suffix? "-guix-command.drv"
(derivation-input-path input)))
(derivation-inputs drv))))
(define (channel-instances->manifest instances)
"Return a profile manifest with entries for all of INSTANCES, a list of
channel instances."
(define instance->entry
(match-lambda
((instance drv)
(let ((commit (channel-instance-commit instance))
(channel (channel-instance-channel instance)))
(with-monad %store-monad
(return (manifest-entry
(name (symbol->string (channel-name channel)))
(version (string-take commit 7))
(item (if (guix-channel? channel)
(if (old-style-guix? drv)
(whole-package-for-legacy
(string-append name "-" version)
drv)
drv)
drv))
(properties
`((source (repository
(version 0)
(url ,(channel-url channel))
(branch ,(channel-branch channel))
(commit ,commit))))))))))))
(mlet* %store-monad ((derivations (channel-instance-derivations instances))
(entries (mapm %store-monad instance->entry
(zip instances derivations))))
(return (manifest entries))))
(define (channel-instances->derivation instances)
"Return the derivation of the profile containing INSTANCES, a list of
channel instances."
(mlet %store-monad ((manifest (channel-instances->manifest instances)))
(profile-derivation manifest)))
(define latest-channel-instances*
(store-lift latest-channel-instances))
(define* (latest-channel-derivation #:optional (channels %default-channels))
"Return as a monadic value the derivation that builds the profile for the
latest instances of CHANNELS."
(mlet %store-monad ((instances (latest-channel-instances* channels)))
(channel-instances->derivation instances)))