[bug#30572] [PATCH 5/7] docker: Allow the addition of extra files into the image.

[Chris Marusich <cmmarusich@gmail.com>]

* guix/docker.scm (build-docker-image): Add #:extra-items-dir keyword
  argument.
---
 guix/docker.scm | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/guix/docker.scm b/guix/docker.scm
index 693b4426f..1b9b36a3b 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -107,7 +107,8 @@ return \"a\"."
                              (symlinks '())
                              (system (utsname:machine (uname)))
                              (creation-time (current-time time-utc))
-                             (tmpdir "/tmp"))
+                             (tmpdir "/tmp")
+                             extra-items-dir)
   "Write to IMAGE a Docker image archive from the given store PATH.  The image
 contains the closure of PATH, as specified in CLOSURE (a file produced by
 #:references-graphs).  SYMLINKS must be a list of (SOURCE -> TARGET) tuples
@@ -121,7 +122,12 @@ CREATION-TIME, a SRFI-19 time-utc object, as the creation time in metadata.
 TMPDIR is the name of the temporary working directory to use.  This can be
 useful if you need to use a specific temporary directory, for example because
 the default temporary directory lies on a file system with insufficient
-space."
+space.
+
+EXTRA-ITEMS-DIR is the name of a directory containing extra files to add to
+the image; the entire directory tree rooted at EXTRA-ITEMS-DIR will be copied
+into the root directory of the image, so a file EXTRA-ITEMS-DIR/foo will wind
+up at /foo in the final Docker image."
   (let ((directory (string-append tmpdir "/docker-image")) ;temporary working directory
         (closure (canonicalize-path closure))
         (id (docker-id path))
@@ -165,9 +171,14 @@ space."
                                   (append %tar-determinism-options
                                           items
                                           (map symlink-source symlinks))))
-                    (for-each delete-file-recursively
-                              (map (compose topmost-component symlink-source)
-                                   symlinks)))))
+                    (begin
+                      (for-each delete-file-recursively
+                                (map (compose topmost-component symlink-source)
+                                     symlinks))
+                      (zero? (apply system* "tar" "-C" extra-items-dir
+                                    "-rf" "layer.tar"
+                                    (append %tar-determinism-options
+                                            '("."))))))))
 
            (with-output-to-file "config.json"
              (lambda ()
-- 
2.15.1