[PATCH v3 22/30] tests/docker: add --registry support to tooling

["Alex Bennée" <alex.bennee@linaro.org>]

This allows us to point the tools towards a registry from which they
can grab pre-built layers instead of doing everything from scratch
each time. To enable this we need to be using the DOCKER_BUILDKIT
engine.

[AJB: note registry.gitlab.com/stsquad/qemu is for my testing, the
final version will see DOCKER_REGISTRY default to registry.gitlab.com/qemu-project/qemu]

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v2
  - add a pull stage to pull images from the registry
  - enable BUILDKIT and BUILDKIT_INLINE_CACHE
  - don't invoke BUILDKIT on Travis
---
 tests/docker/Makefile.include |  3 +++
 tests/docker/docker.py        | 37 +++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/tests/docker/Makefile.include b/tests/docker/Makefile.include
index 6d6ced1e463..8139e8467d4 100644
--- a/tests/docker/Makefile.include
+++ b/tests/docker/Makefile.include
@@ -13,6 +13,7 @@ DOCKER_IMAGES := $(sort $(notdir $(basename $(wildcard $(DOCKER_FILES_DIR)/*.doc
 DOCKER_TARGETS := $(patsubst %,docker-image-%,$(DOCKER_IMAGES))
 # Use a global constant ccache directory to speed up repetitive builds
 DOCKER_CCACHE_DIR := $$HOME/.cache/qemu-docker-ccache
+DOCKER_REGISTRY := $(if $(REGISTRY),$(REGISTRY),registry.gitlab.com/stsquad/qemu)
 
 DOCKER_TESTS := $(notdir $(shell \
 	find $(SRC_PATH)/tests/docker/ -name 'test-*' -type f))
@@ -57,6 +58,7 @@ docker-image-%: $(DOCKER_FILES_DIR)/%.docker
 	$(call quiet-command,\
 		$(DOCKER_SCRIPT) build -t qemu/$* -f $< \
 		$(if $V,,--quiet) $(if $(NOCACHE),--no-cache) \
+		$(if $(DOCKER_REGISTRY),--registry $(DOCKER_REGISTRY)) \
 		$(if $(NOUSER),,--add-current-user) \
 		$(if $(EXTRA_FILES),--extra-files $(EXTRA_FILES))\
 		$(if $(EXECUTABLE),--include-executable=$(EXECUTABLE)),\
@@ -213,6 +215,7 @@ endif
 	@echo '                         Include extra files in image.'
 	@echo '    ENGINE=auto/docker/podman'
 	@echo '                         Specify which container engine to run.'
+	@echo '    REGISTRY=url         Cache builds from registry (default:$(DOCKER_REGISTRY))'
 
 # This rule if for directly running against an arbitrary docker target.
 # It is called by the expanded docker targets (e.g. make
diff --git a/tests/docker/docker.py b/tests/docker/docker.py
index cc6f76caa60..a31ac287150 100755
--- a/tests/docker/docker.py
+++ b/tests/docker/docker.py
@@ -221,6 +221,13 @@ class Docker(object):
     """ Running Docker commands """
     def __init__(self):
         self._command = _guess_engine_command()
+
+        if "docker" in self._command and "TRAVIS" not in os.environ:
+            os.environ["DOCKER_BUILDKIT"] = "1"
+            self._buildkit = True
+        else:
+            self._buildkit = False
+
         self._instance = None
         atexit.register(self._kill_instances)
         signal.signal(signal.SIGTERM, self._kill_instances)
@@ -289,10 +296,20 @@ class Docker(object):
         return labels.get("com.qemu.dockerfile-checksum", "")
 
     def build_image(self, tag, docker_dir, dockerfile,
-                    quiet=True, user=False, argv=None, extra_files_cksum=[]):
+                    quiet=True, user=False, argv=None, registry=None,
+                    extra_files_cksum=[]):
         if argv is None:
             argv = []
 
+        if registry is not None:
+            dockerfile = dockerfile.replace("FROM qemu/",
+                                            "FROM %s/qemu/" %
+                                            (registry))
+            # see if we can fetch a cache copy, may fail...
+            pull_args = ["pull", "%s/%s" % (registry, tag)]
+            self._do(pull_args, quiet=quiet)
+
+
         tmp_df = tempfile.NamedTemporaryFile(mode="w+t",
                                              encoding='utf-8',
                                              dir=docker_dir, suffix=".docker")
@@ -313,8 +330,17 @@ class Docker(object):
 
         tmp_df.flush()
 
-        self._do_check(["build", "-t", tag, "-f", tmp_df.name] + argv +
-                       [docker_dir],
+        build_args = ["build", "-t", tag, "-f", tmp_df.name]
+        if self._buildkit:
+            build_args += ["--build-arg", "BUILDKIT_INLINE_CACHE=1"]
+
+        if registry is not None:
+            cache = "%s/%s" % (registry, tag)
+            build_args += ["--cache-from", cache]
+        build_args += argv
+        build_args += [docker_dir]
+
+        self._do_check(build_args,
                        quiet=quiet)
 
     def update_image(self, tag, tarball, quiet=True):
@@ -403,6 +429,8 @@ class BuildCommand(SubCommand):
         parser.add_argument("--add-current-user", "-u", dest="user",
                             action="store_true",
                             help="Add the current user to image's passwd")
+        parser.add_argument("--registry", "-r",
+                            help="cache from docker registry")
         parser.add_argument("-t", dest="tag",
                             help="Image Tag")
         parser.add_argument("-f", dest="dockerfile",
@@ -458,7 +486,8 @@ class BuildCommand(SubCommand):
                      for k, v in os.environ.items()
                      if k.lower() in FILTERED_ENV_NAMES]
             dkr.build_image(tag, docker_dir, dockerfile,
-                            quiet=args.quiet, user=args.user, argv=argv,
+                            quiet=args.quiet, user=args.user,
+                            argv=argv, registry=args.registry,
                             extra_files_cksum=cksum)
 
             rmtree(docker_dir)
-- 
2.20.1