docker.py: fix fetching of FROM layers

This worked on a system that was already bootstrapped because the
stage 2 images already existed even if they wouldn't be used. What we
should have pulled down was the FROM line containers first because
building on gitlab doesn't have the advantage of using our build
system to build the pre-requisite bits.

We still pull the image we want to build just in case we can use the
cached data.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200713200415.26214-4-alex.bennee@linaro.org>

diff --git a/tests/docker/docker.py b/tests/docker/docker.py
index 2d67bbd15a5b403b229dc5f764851441b2f18609..c9f20d8d093bed4bd96edc8e1f1d83ab21a77d6d 100755 (executable)
--- a/tests/docker/docker.py
+++ b/tests/docker/docker.py
@@ -306,14 +306,18 @@ class Docker(object):
         checksum = _text_checksum(_dockerfile_preprocess(dockerfile))
 
         if registry is not None:
-            # see if we can fetch a cache copy, may fail...
-            pull_args = ["pull", "%s/%s" % (registry, tag)]
-            if self._do(pull_args, quiet=quiet) == 0:
+            sources = re.findall("FROM qemu\/(.*)", dockerfile)
+            # Fetch any cache layers we can, may fail
+            for s in sources:
+                pull_args = ["pull", "%s/qemu/%s" % (registry, s)]
+                if self._do(pull_args, quiet=quiet) != 0:
+                    registry = None
+                    break
+            # Make substitutions
+            if registry is not None:
                 dockerfile = dockerfile.replace("FROM qemu/",
                                                 "FROM %s/qemu/" %
                                                 (registry))
-            else:
-                registry = None
 
         tmp_df = tempfile.NamedTemporaryFile(mode="w+t",
                                              encoding='utf-8',
@@ -339,6 +343,8 @@ class Docker(object):
             build_args += ["--build-arg", "BUILDKIT_INLINE_CACHE=1"]
 
         if registry is not None:
+            pull_args = ["pull", "%s/%s" % (registry, tag)]
+            self._do(pull_args, quiet=quiet)
             cache = "%s/%s" % (registry, tag)
             build_args += ["--cache-from", cache]
         build_args += argv