feat: expose partitions to the lifecycle service (#292)

Signed-off-by: Sergio Schvezov <[email protected]>
Co-authored-by: Alex Lowe <[email protected]>

craft_application/application.py

@@ -130,6 +130,7 @@ def __init__(
         # When build_secrets are enabled, this contains the secret info to pass to
         # managed instances.
         self._secrets: secrets.BuildSecrets | None = None
+        self._partitions: list[str] | None = None
         # Cached project object, allows only the first time we load the project
         # to specify things like the project directory.
         # This is set as a private attribute in order to discourage real application
@@ -219,6 +220,7 @@ def _configure_services(self, provider_name: str | None) -> None:
             cache_dir=self.cache_dir,
             work_dir=self._work_dir,
             build_plan=self._build_plan,
+            partitions=self._partitions,
         )
         self.services.set_kwargs(
             "provider",
@@ -288,6 +290,9 @@ def get_project(
         GrammarAwareProject.validate_grammar(yaml_data)
 
         build_on = host_arch
+
+        # Setup partitions, some projects require the yaml data, most will not
+        self._partitions = self._setup_partitions(yaml_data)
         yaml_data = self._transform_project_yaml(yaml_data, build_on, build_for)
         self.__project = self.app.ProjectClass.from_yaml_data(yaml_data, project_path)
 
@@ -608,18 +613,32 @@ def _transform_project_yaml(
     def _expand_environment(self, yaml_data: dict[str, Any]) -> None:
         """Perform expansion of project environment variables."""
         environment_vars = self._get_project_vars(yaml_data)
+        project_dirs = craft_parts.ProjectDirs(
+            work_dir=self._work_dir, partitions=self._partitions
+        )
+
         info = craft_parts.ProjectInfo(
             application_name=self.app.name,  # not used in environment expansion
             cache_dir=pathlib.Path(),  # not used in environment expansion
             project_name=yaml_data.get("name", ""),
-            project_dirs=craft_parts.ProjectDirs(work_dir=self._work_dir),
+            project_dirs=project_dirs,
             project_vars=environment_vars,
+            partitions=self._partitions,
         )
 
         self._set_global_environment(info)
 
         craft_parts.expand_environment(yaml_data, info=info)
 
+    def _setup_partitions(self, yaml_data: dict[str, Any]) -> list[str] | None:
+        """Return partitions to be used.
+
+        When returning you will also need to ensure that the feature is enabled
+        on Application instantiation craft_parts.Features(partitions_enabled=True)
+        """
+        _ = yaml_data
+        return None
+
     def _get_project_vars(self, yaml_data: dict[str, Any]) -> dict[str, str]:
         """Return a dict with project variables to be expanded."""
         pvars: dict[str, str] = {}

craft_application/services/lifecycle.py

@@ -134,12 +134,14 @@ def __init__(
         work_dir: Path | str,
         cache_dir: Path | str,
         build_plan: list[models.BuildInfo],
+        partitions: list[str] | None = None,
         **lifecycle_kwargs: Any,  # noqa: ANN401 - eventually used in an Any
     ) -> None:
         super().__init__(app, services, project=project)
         self._work_dir = work_dir
         self._cache_dir = cache_dir
         self._build_plan = build_plan
+        self._partitions = partitions
         self._manager_kwargs = lifecycle_kwargs
         self._lcm: LifecycleManager = None  # type: ignore[assignment]
 
@@ -190,6 +192,7 @@ def _init_lifecycle_manager(self) -> LifecycleManager:
                 project_vars_part_name=self._project.adopt_info,
                 project_vars=self._project_vars,
                 track_stage_packages=True,
+                partitions=self._partitions,
                 **self._manager_kwargs,
             )
         except PartsError as err:

tests/conftest.py

@@ -132,13 +132,25 @@ def full_build_plan(mocker) -> list[models.BuildInfo]:
     return build_plan
 
 
+@pytest.fixture()
+def enable_partitions() -> Iterator[craft_parts.Features]:
+    """Enable the partitions feature in craft_parts for the relevant test."""
+    enable_overlay = craft_parts.Features().enable_overlay
+
+    craft_parts.Features.reset()
+    yield craft_parts.Features(enable_overlay=enable_overlay, enable_partitions=True)
+    craft_parts.Features.reset()
+
+
 @pytest.fixture()
 def enable_overlay() -> Iterator[craft_parts.Features]:
     """Enable the overlay feature in craft_parts for the relevant test."""
     if not os.getenv("CI") and not shutil.which("fuse-overlayfs"):
         pytest.skip("fuse-overlayfs not installed, skipping overlay tests.")
+
+    enable_partitions = craft_parts.Features().enable_partitions
     craft_parts.Features.reset()
-    yield craft_parts.Features(enable_overlay=True)
+    yield craft_parts.Features(enable_overlay=True, enable_partitions=enable_partitions)
     craft_parts.Features.reset()
 
 

tests/unit/services/test_lifecycle.py

@@ -306,6 +306,26 @@ def test_init_with_feature_package_repositories(
     assert service._lcm._project_info.package_repositories == package_repositories
 
 
+@pytest.mark.usefixtures("enable_partitions")
+def test_init_with_partitions(
+    app_metadata, fake_project, fake_services, tmp_path, fake_build_plan
+):
+    service = lifecycle.LifecycleService(
+        app_metadata,
+        fake_services,
+        project=fake_project,
+        work_dir=tmp_path,
+        cache_dir=tmp_path,
+        platform=None,
+        build_plan=fake_build_plan,
+        partitions=["default", "mypartition"],
+    )
+    assert service._lcm is None
+    service.setup()
+    assert service._lcm is not None
+    assert service._lcm._project_info.partitions == ["default", "mypartition"]
+
+
 def test_prime_dir(lifecycle_service, tmp_path):
     prime_dir = lifecycle_service.prime_dir
 

tests/unit/test_application.py

@@ -1178,3 +1178,64 @@ def test_process_grammar_no_match(grammar_app, mocker):
     project = grammar_app.get_project()
     # "source" is empty because "i386" doesn't match any of the grammar statements.
     assert project.parts["mypart"]["source"] is None
+
+
+class FakePartitionsApplication(FakeApplication):
+    """A partition using FakeApplication."""
+
+    @override
+    def _setup_partitions(self, yaml_data) -> list[str]:
+        _ = yaml_data
+        return ["default", "mypartition"]
+
+
+@pytest.fixture()
+def environment_partitions_project(monkeypatch, tmp_path):
+    project_dir = tmp_path / "project"
+    project_dir.mkdir()
+    project_path = project_dir / "testcraft.yaml"
+    project_path.write_text(
+        dedent(
+            """
+        name: myproject
+        version: 1.2.3
+        parts:
+          mypart:
+            plugin: nil
+            source-tag: v$CRAFT_PROJECT_VERSION
+            override-stage: |
+              touch $CRAFT_STAGE/default
+              touch $CRAFT_MYPARTITION_STAGE/partition
+            override-prime: |
+              touch $CRAFT_PRIME/default
+              touch $CRAFT_MYPARTITION_PRIME/partition
+        """
+        )
+    )
+    monkeypatch.chdir(project_dir)
+
+    return project_path
+
+
+@pytest.mark.usefixtures("enable_partitions")
+@pytest.mark.usefixtures("environment_partitions_project")
+def test_partition_application_expand_environment(app_metadata, fake_services):
+    app = FakePartitionsApplication(app_metadata, fake_services)
+    project = app.get_project(build_for=get_host_architecture())
+
+    assert craft_parts.Features().enable_partitions is True
+    # Make sure the project is loaded correctly (from the cwd)
+    assert project is not None
+    assert project.parts["mypart"]["source-tag"] == "v1.2.3"
+    assert project.parts["mypart"]["override-stage"] == dedent(
+        f"""\
+        touch {app.project_dir}/stage/default
+        touch {app.project_dir}/partitions/mypartition/stage/partition
+    """
+    )
+    assert project.parts["mypart"]["override-prime"] == dedent(
+        f"""\
+        touch {app.project_dir}/prime/default
+        touch {app.project_dir}/partitions/mypartition/prime/partition
+    """
+    )