osbuild: allow additional an additional build-pipeline to be prepended

The best practice for creating a pipeline should be to include at least
one level of build-pipelines. This makes sure that the tools used to
generate the target image are well-defined.

In principle one could add several layers, though in pracite, one would
hope that the envinment used to build the buildroot does not affect the
final image (and as we anyway cannot recurr indefinitely, we fall back
to simply using the host system in this case).

This only makes sense, if the contents of the host system truly does not
affect the generated image, and as such we do not include any information
about the host when computing the hash that identifies a pipeline.

In fact, any image could be used in its place, as long as the required
tools are present. This commit takes advantage of that fact. Rather than
run a pipeline with the host as the build root, take a second pipeline
to generate the buildroot, but do not include this when computing the
pipeline id (so it is different from simply editing the original JSON).

This is necessary so we can use the same pipelines on significantly
different host systems (run with different --bulid-pipeline arguments).
In particular, it allows our test pipelines that generate f30 images
to be run unmodified on Travis (which runs Ubuntu).

Signed-off-by: Tom Gundersen <teg@jklm.no>

osbuild/__main__.py

@@ -14,6 +14,8 @@ def main():
     parser = argparse.ArgumentParser(description="Build operating system images")
     parser.add_argument("pipeline_path", metavar="PIPELINE",
                         help="json file containing the pipeline that should be built")
+    parser.add_argument("--build-pipeline", metavar="PIPELINE", type=os.path.abspath,
+                        help="json file containing the pipeline to create a build environment")
     parser.add_argument("--store", metavar="DIRECTORY", type=os.path.abspath,
                         default=".osbuild/store",
                         help="the directory where intermediary os trees are stored")
@@ -27,6 +29,11 @@ def main():
     with open(args.pipeline_path) as f:
         pipeline = osbuild.load(json.load(f))
 
+    if args.build_pipeline:
+        with open(args.build_pipeline) as f:
+            build = osbuild.load(json.load(f))
+        pipeline.prepend_build_pipeline(build)
+
     try:
         pipeline.run(args.output_dir, args.store, interactive=True, libdir=args.libdir)
     except KeyboardInterrupt:

osbuild/pipeline.py

@@ -151,6 +151,12 @@ class Pipeline:
     def set_assembler(self, name, options=None):
         self.assembler = Assembler(name, options or {})
 
+    def prepend_build_pipeline(self, build):
+        pipeline = self
+        while pipeline.build:
+            pipeline = pipeline.build
+        pipeline.build = build
+
     def description(self):
         description = {}
         if self.build:

test/__main__.py

@@ -31,6 +31,8 @@ def test_firewall(extract_dir):
 if __name__ == '__main__':
     parser = argparse.ArgumentParser(description='Run integration tests')
     parser.add_argument('--list', dest='list', action='store_true', help='list test cases')
+    parser.add_argument('--build-pipeline', dest='build_pipeline', metavar='PIPELINE',
+                        type=os.path.abspath, help='the build pipeline to run tests in')
     parser.add_argument('--case', dest='specific_case', metavar='TEST_CASE', help='run single test case')
     args = parser.parse_args()
 
@@ -41,6 +43,7 @@ if __name__ == '__main__':
     f30_boot = IntegrationTestCase(
         name="f30-boot",
         pipeline="f30-boot.json",
+        build_pipeline=args.build_pipeline,
         output_image="f30-boot.qcow2",
         test_cases=[test_is_system_running],
         type=IntegrationTestType.BOOT_WITH_QEMU
@@ -48,6 +51,7 @@ if __name__ == '__main__':
     timezone = IntegrationTestCase(
         name="timezone",
         pipeline="timezone.json",
+        build_pipeline=args.build_pipeline,
         output_image="timezone.tar.xz",
         test_cases=[test_timezone],
         type=IntegrationTestType.EXTRACT
@@ -55,6 +59,7 @@ if __name__ == '__main__':
     firewall = IntegrationTestCase(
         name="firewall",
         pipeline="firewall.json",
+        build_pipeline=args.build_pipeline,
         output_image="firewall.tar.xz",
         test_cases=[test_firewall],
         type=IntegrationTestType.EXTRACT

test/integration_tests/build.py

@@ -5,8 +5,10 @@ import sys
 from .config import *
 
 
-def run_osbuild(pipeline: str, check=True):
+def run_osbuild(pipeline: str, build_pipeline: str, check=True):
     cmd = OSBUILD + ["--store", OBJECTS, "-o", OUTPUT_DIR, pipeline]
+    if build_pipeline:
+        cmd += ["--build-pipeline", build_pipeline]
     logging.info(f"Running osbuild: {cmd}")
     osbuild = subprocess.run(cmd, capture_output=True)
     if osbuild.returncode != 0:
@@ -21,5 +23,5 @@ def run_osbuild(pipeline: str, check=True):
     return osbuild.returncode
 
 
-def build_testing_image(pipeline_full_path):
-    run_osbuild(pipeline_full_path)
+def build_testing_image(pipeline_full_path, build_pipeline_full_path):
+    run_osbuild(pipeline_full_path, build_pipeline_full_path)

test/integration_tests/test_case.py

@@ -16,12 +16,13 @@ class IntegrationTestType(Enum):
 class IntegrationTestCase:
     name: str
     pipeline: str
+    build_pipeline: str
     output_image: str
     test_cases: List[Callable[[Any], None]]
     type: IntegrationTestType
 
     def run(self):
-        run_osbuild(rel_path(f"pipelines/{self.pipeline}"))
+        run_osbuild(rel_path(f"pipelines/{self.pipeline}"), self.build_pipeline)
         if self.type == IntegrationTestType.BOOT_WITH_QEMU:
             self.run_and_test()
         else: