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authorRicardo Wurmus <ricardo.wurmus@mdc-berlin.de>2017-01-03 16:20:15 +0100
committerRicardo Wurmus <rekado@elephly.net>2017-01-06 16:44:00 +0100
commit03476a23ff2d4175b7d3c808726178f764359bec (patch)
treeb26d889f05f7685501d58aac3aa313dccb53fade
parent3a3bf2f81977a1ff4a74957753340aab57f5a12d (diff)
guix: Add Docker image export.
* guix/docker.scm: New file. * Makefile.am (MODULES): Register it. * guix/scripts/archive.scm (show-help, %options, guix-archive): Add support for "--format". * doc/guix.texi (Invoking guix archive): Document it.
-rw-r--r--Makefile.am1
-rw-r--r--doc/guix.texi18
-rw-r--r--guix/docker.scm127
-rw-r--r--guix/scripts/archive.scm17
4 files changed, 161 insertions, 2 deletions
diff --git a/Makefile.am b/Makefile.am
index 1a66fff505..3e147df2e0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -160,6 +160,7 @@ MODULES = \
if HAVE_GUILE_JSON
MODULES += \
+ guix/docker.scm \
guix/import/github.scm \
guix/import/json.scm \
guix/import/crate.scm \
diff --git a/doc/guix.texi b/doc/guix.texi
index adc7fefcae..e52382e976 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -2394,7 +2394,7 @@ what you should use in this case (@pxref{Invoking guix copy}).
@cindex nar, archive format
@cindex normalized archive (nar)
-Archives are stored in the ``normalized archive'' or ``nar'' format, which is
+By default archives are stored in the ``normalized archive'' or ``nar'' format, which is
comparable in spirit to `tar', but with differences
that make it more appropriate for our purposes. First, rather than
recording all Unix metadata for each file, the nar format only mentions
@@ -2410,6 +2410,9 @@ verifies the signature and rejects the import in case of an invalid
signature or if the signing key is not authorized.
@c FIXME: Add xref to daemon doc about signatures.
+Optionally, archives can be exported as a Docker image in the tar
+archive format using @code{--format=docker}.
+
The main options are:
@table @code
@@ -2438,6 +2441,19 @@ Read a list of store file names from the standard input, one per line,
and write on the standard output the subset of these files missing from
the store.
+@item -f
+@item --format=@var{FMT}
+@cindex docker, export
+@cindex export format
+Specify the export format. Acceptable arguments are @code{nar} and
+@code{docker}. The default is the nar format. When the format is
+@code{docker}, recursively export the specified store directory as a
+Docker image in tar archive format, as specified in
+@uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
+version 1.2.0 of the Docker Image Specification}. Using
+@code{--format=docker} implies @code{--recursive}. The generated
+archive can be loaded by Docker using @command{docker load}.
+
@item --generate-key[=@var{parameters}]
@cindex signing, archives
Generate a new key pair for the daemon. This is a prerequisite before
diff --git a/guix/docker.scm b/guix/docker.scm
new file mode 100644
index 0000000000..dbe1e5351c
--- /dev/null
+++ b/guix/docker.scm
@@ -0,0 +1,127 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 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 docker)
+ #:use-module (guix hash)
+ #:use-module (guix store)
+ #:use-module (guix utils)
+ #:use-module ((guix build utils)
+ #:select (delete-file-recursively
+ with-directory-excursion))
+ #:use-module (json)
+ #:use-module (rnrs bytevectors)
+ #:use-module (ice-9 match)
+ #:export (build-docker-image))
+
+;; Generate a 256-bit identifier in hexadecimal encoding for the Docker image
+;; containing the closure at PATH.
+(define docker-id
+ (compose bytevector->base16-string sha256 string->utf8))
+
+(define (layer-diff-id layer)
+ "Generate a layer DiffID for the given LAYER archive."
+ (string-append "sha256:" (bytevector->base16-string (file-sha256 layer))))
+
+;; This is the semantic version of the JSON metadata schema according to
+;; https://github.com/docker/docker/blob/master/image/spec/v1.2.md
+;; It is NOT the version of the image specification.
+(define schema-version "1.0")
+
+(define (image-description id time)
+ "Generate a simple image description."
+ `((id . ,id)
+ (created . ,time)
+ (container_config . #nil)))
+
+(define (generate-tag path)
+ "Generate an image tag for the given PATH."
+ (match (string-split (basename path) #\-)
+ ((hash name . rest) (string-append name ":" hash))))
+
+(define (manifest path id)
+ "Generate a simple image manifest."
+ `(((Config . "config.json")
+ (RepoTags . (,(generate-tag path)))
+ (Layers . (,(string-append id "/layer.tar"))))))
+
+;; According to the specifications this is required for backwards
+;; compatibility. It duplicates information provided by the manifest.
+(define (repositories path id)
+ "Generate a repositories file referencing PATH and the image ID."
+ `((,(generate-tag path) . ((latest . ,id)))))
+
+;; See https://github.com/opencontainers/image-spec/blob/master/config.md
+(define (config layer time arch)
+ "Generate a minimal image configuration for the given LAYER file."
+ ;; "architecture" must be values matching "platform.arch" in the
+ ;; runtime-spec at
+ ;; https://github.com/opencontainers/runtime-spec/blob/v1.0.0-rc2/config.md#platform
+ `((architecture . ,arch)
+ (comment . "Generated by GNU Guix")
+ (created . ,time)
+ (config . #nil)
+ (container_config . #nil)
+ (os . "linux")
+ (rootfs . ((type . "layers")
+ (diff_ids . (,(layer-diff-id layer)))))))
+
+(define* (build-docker-image path #:key system)
+ "Generate a Docker image archive from the given store PATH. The image
+contains the closure of the given store item."
+ (let ((id (docker-id path))
+ (time (strftime "%FT%TZ" (localtime (current-time))))
+ (name (string-append (getcwd)
+ "/docker-image-" (basename path) ".tar"))
+ (arch (match system
+ ("x86_64-linux" "amd64")
+ ("i686-linux" "386")
+ ("armhf-linux" "arm")
+ ("mips64el-linux" "mips64le"))))
+ (and (call-with-temporary-directory
+ (lambda (directory)
+ (with-directory-excursion directory
+ ;; Add symlink from /bin to /gnu/store/.../bin
+ (symlink (string-append path "/bin") "bin")
+
+ (mkdir id)
+ (with-directory-excursion id
+ (with-output-to-file "VERSION"
+ (lambda () (display schema-version)))
+ (with-output-to-file "json"
+ (lambda () (scm->json (image-description id time))))
+
+ ;; Wrap it up
+ (let ((items (with-store store
+ (requisites store (list path)))))
+ (and (zero? (apply system* "tar" "-cf" "layer.tar"
+ (cons "../bin" items)))
+ (delete-file "../bin"))))
+
+ (with-output-to-file "config.json"
+ (lambda ()
+ (scm->json (config (string-append id "/layer.tar")
+ time arch))))
+ (with-output-to-file "manifest.json"
+ (lambda ()
+ (scm->json (manifest path id))))
+ (with-output-to-file "repositories"
+ (lambda ()
+ (scm->json (repositories path id)))))
+ (and (zero? (system* "tar" "-C" directory "-cf" name "."))
+ (begin (delete-file-recursively directory) #t))))
+ name)))
diff --git a/guix/scripts/archive.scm b/guix/scripts/archive.scm
index 7e432351ed..6eba9e0008 100644
--- a/guix/scripts/archive.scm
+++ b/guix/scripts/archive.scm
@@ -1,5 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2017 Ricardo Wurmus <rekado@elephly.net>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -30,6 +31,7 @@
#:use-module (guix ui)
#:use-module (guix pki)
#:use-module (guix pk-crypto)
+ #:use-module (guix docker)
#:use-module (guix scripts)
#:use-module (guix scripts build)
#:use-module (gnu packages)
@@ -63,6 +65,8 @@ Export/import one or more packages from/to the store.\n"))
(display (_ "
--export export the specified files/packages to stdout"))
(display (_ "
+ --format=FMT export files/packages in the specified format FMT"))
+ (display (_ "
-r, --recursive combined with '--export', include dependencies"))
(display (_ "
--import import from the archive passed on stdin"))
@@ -117,6 +121,9 @@ Export/import one or more packages from/to the store.\n"))
(option '("export") #f #f
(lambda (opt name arg result)
(alist-cons 'export #t result)))
+ (option '(#\f "format") #t #f
+ (lambda (opt name arg result . rest)
+ (alist-cons 'format arg result)))
(option '(#\r "recursive") #f #f
(lambda (opt name arg result)
(alist-cons 'export-recursive? #t result)))
@@ -331,7 +338,15 @@ the input port."
(else
(with-store store
(cond ((assoc-ref opts 'export)
- (export-from-store store opts))
+ (cond ((equal? (assoc-ref opts 'format) "docker")
+ (match (car opts)
+ (('argument . (? store-path? item))
+ (format #t "~a\n"
+ (build-docker-image
+ item
+ #:system (assoc-ref opts 'system))))
+ (_ (leave (_ "argument must be a direct store path~%")))))
+ (_ (export-from-store store opts))))
((assoc-ref opts 'import)
(import-paths store (current-input-port)))
((assoc-ref opts 'missing)