From 03476a23ff2d4175b7d3c808726178f764359bec Mon Sep 17 00:00:00 2001 From: Ricardo Wurmus Date: Tue, 3 Jan 2017 16:20:15 +0100 Subject: 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. --- guix/docker.scm | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 guix/docker.scm (limited to 'guix/docker.scm') 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 +;;; +;;; 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 . + +(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))) -- cgit v1.2.3