pack: 'docker' backend records the profile's search paths.

* guix/docker.scm (config): Add #:environment parameter and honor it.
(build-docker-image): Likewise, and pass it to 'config'.
* guix/scripts/pack.scm (docker-image): Import (guix profiles) and (guix
search-paths).  Call 'profile-search-paths' and pass #:environment to
'build-docker-image'.
* gnu/tests/docker.scm (run-docker-test)["Load docker image and run it"]:
Add example that expects (json) to be available.
* gnu/tests/docker.scm (build-tarball&run-docker-test): Replace
%BOOTSTRAP-GUILE by GUILE-2.2 and GUILE-JSON in the environment.

1 files changed, 13 insertions, 4 deletions

diff --git a/guix/docker.scm b/guix/docker.scm
index 7fe83d9797..b1bd226fa1 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -73,7 +73,7 @@
   `((,(generate-tag path) . ((latest . ,id)))))
 
 ;; See https://github.com/opencontainers/image-spec/blob/master/config.md
-(define* (config layer time arch #:key entry-point)
+(define* (config layer time arch #:key entry-point (environment '()))
   "Generate a minimal image configuration for the given LAYER file."
   ;; "architecture" must be values matching "platform.arch" in the
   ;; runtime-spec at
@@ -81,9 +81,13 @@
   `((architecture . ,arch)
     (comment . "Generated by GNU Guix")
     (created . ,time)
-    (config . ,(if entry-point
-                   `((entrypoint . ,entry-point))
-                   #nil))
+    (config . ,`((env . ,(map (match-lambda
+                                ((name . value)
+                                 (string-append name "=" value)))
+                              environment))
+                 ,@(if entry-point
+                       `((entrypoint . ,entry-point))
+                       '())))
     (container_config . #nil)
     (os . "linux")
     (rootfs . ((type . "layers")
@@ -113,6 +117,7 @@ return \"a\"."
                              (system (utsname:machine (uname)))
                              database
                              entry-point
+                             (environment '())
                              compressor
                              (creation-time (current-time time-utc)))
   "Write to IMAGE a Docker image archive containing the given PATHS.  PREFIX
@@ -124,6 +129,9 @@ When DATABASE is true, copy it to /var/guix/db in the image and create
 When ENTRY-POINT is true, it must be a list of strings; it is stored as the
 entry point in the Docker image JSON structure.
 
+ENVIRONMENT must be a list of name/value pairs.  It specifies the environment
+variables that must be defined in the resulting image.
+
 SYMLINKS must be a list of (SOURCE -> TARGET) tuples describing symlinks to be
 created in the image, where each TARGET is relative to PREFIX.
 TRANSFORMATIONS must be a list of (OLD -> NEW) tuples describing how to
@@ -234,6 +242,7 @@ SRFI-19 time-utc object, as the creation time in metadata."
         (lambda ()
           (scm->json (config (string-append id "/layer.tar")
                              time arch
+                             #:environment environment
                              #:entry-point entry-point))))
       (with-output-to-file "manifest.json"
         (lambda ()