channels: Add optional directory to channel metadata.

* guix/channels.scm (<channel-metadata>): Add directory slot.  Update users.
(read-channel-metadata-from-source): New function.
(standard-module-derivation): Use it.
* doc/guix.texi (Package Modules in a Subdirectory): New subsection.
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Jan Nieuwenhuizen 2019-07-13 16:31:50 +02:00
parent bee9f97e0a
commit 53f2164272
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2 changed files with 61 additions and 37 deletions

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@ -3921,6 +3921,19 @@ For the sake of reliability and maintainability, you should avoid dependencies
on channels that you don't control, and you should aim to keep the number of
dependencies to a minimum.
@cindex subdirectory, channels
@subsection Package Modules in a Sub-directory
As a channel author, you may want to keep your channel modules in a
sub-directory. If your modules are in the sub-directory @file{guix}, you must
add a meta-data file @file{.guix-channel} that contains:
@lisp
(channel
(version 0)
(directory "guix"))
@end lisp
@subsection Replicating Guix
@cindex pinning, channels

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@ -1,6 +1,7 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018, 2019 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
;;; Copyright © 2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@ -107,9 +108,10 @@ (define-record-type <channel-instance>
(checkout channel-instance-checkout))
(define-record-type <channel-metadata>
(channel-metadata version dependencies)
(channel-metadata version directory dependencies)
channel-metadata?
(version channel-metadata-version)
(directory channel-metadata-directory)
(dependencies channel-metadata-dependencies))
(define (channel-reference channel)
@ -119,18 +121,18 @@ (define (channel-reference 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")))
(define (read-channel-metadata-from-source source)
"Return a channel-metadata record read from channel's SOURCE/.guix-channel
description file, or return #F if SOURCE/.guix-channel does not exist."
(let ((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) '())))
(let* ((raw (call-with-input-file meta-file read))
(version (and=> (assoc-ref raw 'version) first))
(directory (and=> (assoc-ref raw 'directory) first))
(dependencies (or (assoc-ref raw 'dependencies) '())))
(channel-metadata
version
directory
(map (lambda (item)
(let ((get (lambda* (key #:optional default)
(or (and=> (assoc-ref item key) first) default))))
@ -144,12 +146,18 @@ (define (read-channel-metadata instance)
(commit (get 'commit))))))
dependencies))))))
(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."
(read-channel-metadata-from-source (channel-instance-checkout instance)))
(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)
(($ <channel-metadata> version directory dependencies)
dependencies)))
(define* (latest-channel-instances store channels #:optional (previous-channels '()))
@ -230,36 +238,39 @@ (define (standard-module-derivation name source core dependencies)
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'."
;; 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.
(define build
;; This is code that we'll run in CORE, a Guix instance, with its own
;; modules and so on. That way, we make sure these modules are built for
;; the right Guile version, with the right dependencies, and that they get
;; to see the right (gnu packages …) modules.
(with-extensions dependencies
#~(begin
(use-modules (guix build compile)
(guix build utils)
(srfi srfi-26))
(let* ((metadata (read-channel-metadata-from-source source))
(directory (and=> metadata channel-metadata-directory)))
(define go
(string-append #$output "/lib/guile/" (effective-version)
"/site-ccache"))
(define scm
(string-append #$output "/share/guile/site/"
(effective-version)))
(define build
;; This is code that we'll run in CORE, a Guix instance, with its own
;; modules and so on. That way, we make sure these modules are built for
;; the right Guile version, with the right dependencies, and that they get
;; to see the right (gnu packages …) modules.
(with-extensions dependencies
#~(begin
(use-modules (guix build compile)
(guix build utils)
(srfi srfi-26))
(compile-files #$source go
(find-files #$source "\\.scm$"))
(mkdir-p (dirname scm))
(symlink #$source scm)
scm)))
(define go
(string-append #$output "/lib/guile/" (effective-version)
"/site-ccache"))
(define scm
(string-append #$output "/share/guile/site/"
(effective-version)))
(gexp->derivation-in-inferior name build core))
(let* ((subdir (if #$directory
(string-append "/" #$directory)
""))
(source (string-append #$source subdir)))
(compile-files source go (find-files source "\\.scm$"))
(mkdir-p (dirname scm))
(symlink (string-append #$source subdir) scm))
scm)))
(gexp->derivation-in-inferior name build core)))
(define* (build-from-source name source
#:key core verbose? commit