Allow specifying a specific module build to reuse components from

This resolves #1296.

README.rst

@@ -128,6 +128,8 @@ Options:
   rebuilt). For the available options, please look at the "Rebuild Strategies" section below.
 - ``require_overrides`` - the requires to override the modulemd with. The overrides must be to
   existing requires on the modulemd. The expected format is ``{'platform': ['f28', 'f29']}``.
+- ``reuse_components_from`` - the ID or NSVC of the module build to reuse components from. If it's
+  not set, MBS will try to find a compatible module build to reuse components from.
 - ``scratch`` - a boolean indicating if a scratch module build should be performed.
   Only allowed to be ``True`` if the MBS setting ``MODULES_ALLOW_SCRATCH`` is ``True``.
 - ``srpms`` - an optional list of Koji upload URLs of SRPMs to include in a module scratch build.
@@ -357,6 +359,7 @@ parameters::
           "modulemd": "...."
           "name": "testmodule",
           "owner": "mprahl",
+          "reused_module_id": 121,
           "scmurl": "https://src.fedoraproject.org/modules/testmodule.git?#86d9cfe53d20118d863ae051641fc3784d91d981",
           "state": 5,
           "state_name": "ready",
@@ -479,6 +482,7 @@ parameters include:
 - ``new_repo_task_id``
 - ``owner``
 - ``rebuild_strategy``
+- ``reuse_components_from`` - the compatible module that was used for component reuse
 - ``scmurl``
 - ``state`` - Can be the state name or the state ID e.g. ``state=done``. This
   parameter can be given multiple times, in which case or-ing will be used.

docs/REBUILD_STRATEGIES.rst

@@ -75,6 +75,9 @@ module with the following requirements:
 Additionally, if the rebuild strategy for the module being built is ``changed-and-after``, then the
 module to reuse components from will have a rebuild strategy of ``changed-and-after`` or ``all``.
 
+If the user wants to specify the compatible module, they can use the ``reuse_components_from``
+parameter.
+
 
 How the Rebuild Strategies Work
 ===============================

module_build_service/models.py

@@ -877,6 +877,7 @@ class ModuleBuild(MBSBase):
             "build_context": self.build_context,
             "modulemd": self.modulemd,
             "ref_build_context": self.ref_build_context,
+            "reused_module_id": self.reused_module_id,
             "runtime_context": self.runtime_context,
             "state_trace": [
                 {

module_build_service/utils/submit.py

@@ -1014,6 +1014,7 @@ def submit_module_build(username, mmd, params):
                 scmurl=params.get("scmurl"),
                 username=username,
                 rebuild_strategy=params.get("rebuild_strategy"),
+                reused_module_id=params.get("reuse_components_from"),
                 scratch=params.get("scratch"),
                 srpms=params.get("srpms"),
             )

module_build_service/views.py

@@ -305,6 +305,7 @@ class BaseHandler(object):
         "module_name",
         "owner",
         "rebuild_strategy",
+        "reuse_components_from",
         "require_overrides",
         "scmurl",
         "scratch",
@@ -382,6 +383,40 @@ class BaseHandler(object):
         self._validate_dep_overrides_format("buildrequire_overrides")
         self._validate_dep_overrides_format("require_overrides")
 
+        if "reuse_components_from" in self.data:
+            if "rebuild_strategy" in self.data and self.data["rebuild_strategy"] == "all":
+                raise ValidationError(
+                    'You cannot specify the parameter "reuse_components_from" when the '
+                    '"rebuild_strategy" parameter is set to "all"'
+                )
+
+            invalid_identifier_msg = (
+                'The parameter "reuse_components_from" contains an invalid module identifier')
+
+            if isinstance(self.data["reuse_components_from"], int):
+                reuse_module = models.ModuleBuild.get_by_id(
+                    db.session, self.data["reuse_components_from"])
+            elif isinstance(self.data["reuse_components_from"], string_types):
+                try:
+                    n, s, v, c = self.data["reuse_components_from"].split(":")
+                except ValueError:
+                    raise ValidationError(invalid_identifier_msg)
+                reuse_module = models.ModuleBuild.get_build_from_nsvc(db.session, n, s, v, c)
+            else:
+                raise ValidationError(invalid_identifier_msg)
+
+            if not reuse_module:
+                raise ValidationError(
+                    'The module in the parameter "reuse_components_from" could not be found')
+
+            if reuse_module.state != models.BUILD_STATES["ready"]:
+                raise ValidationError(
+                    'The module in the parameter "reuse_components_from" must be in the ready state'
+                )
+
+            # Normalize the value so that it simplifies any code that uses this value
+            self.data["reuse_components_from"] = reuse_module.id
+
 
 class SCMHandler(BaseHandler):
     def validate(self, skip_branch=False, skip_optional_params=False):

tests/test_views/test_views.py

@@ -31,6 +31,7 @@ from os import path, mkdir
 from os.path import basename, dirname, splitext
 from requests.utils import quote
 import hashlib
+import koji
 import pytest
 import re
 import sqlalchemy
@@ -39,7 +40,7 @@ from tests import app, init_data, clean_database, reuse_component_init_data, sta
 from tests import read_staged_data
 from tests.test_scm import base_dir as scm_base_dir
 from module_build_service.errors import UnprocessableEntity
-from module_build_service.models import ModuleBuild
+from module_build_service.models import ModuleBuild, BUILD_STATES
 from module_build_service import db, version
 import module_build_service.config as mbs_config
 import module_build_service.scheduler.handlers.modules
@@ -207,6 +208,7 @@ class TestViews:
         assert data["name"] == "nginx"
         assert data["owner"] == "Moe Szyslak"
         assert data["rebuild_strategy"] == "changed-and-after"
+        assert data["reused_module_id"] is None
         assert data["scmurl"] == \
             "git://pkgs.domain.local/modules/nginx?#ba95886c7a443b36a9ce31abda1f9bef22f2f8c9"
         assert data["scratch"] is False
@@ -2592,3 +2594,112 @@ class TestViews:
             mock_get.assert_called_once_with(expected_url, timeout=15)
         else:
             mock_get.assert_not_called()
+
+    @pytest.mark.parametrize("reuse_components_from", (7, "testmodule:4.3.43:7:00000000"))
+    @patch("module_build_service.auth.get_user", return_value=user)
+    @patch("module_build_service.scm.SCM")
+    def test_submit_build_reuse_components_from(
+        self, mocked_scm, mocked_get_user, reuse_components_from,
+    ):
+        """Test a build submission using the reuse_components_from parameter."""
+        module_to_reuse = db.session.query(ModuleBuild).get(7)
+        module_to_reuse.state = BUILD_STATES["ready"]
+        for c in module_to_reuse.component_builds:
+            c.state = koji.BUILD_STATES["COMPLETE"]
+        db.session.commit()
+
+        FakeSCM(
+            mocked_scm, "testmodule", "testmodule.yaml", "620ec77321b2ea7b0d67d82992dda3e1d67055b4")
+        rv = self.client.post(
+            "/module-build-service/1/module-builds/",
+            data=json.dumps({
+                "branch": "master",
+                "reuse_components_from": reuse_components_from,
+                "scmurl": (
+                    "https://src.stg.fedoraproject.org/modules/testmodule.git?"
+                    "#68931c90de214d9d13feefbd35246a81b6cb8d49"
+                ),
+            }),
+        )
+        data = json.loads(rv.data)
+        assert data["reused_module_id"] == 7
+
+    @pytest.mark.parametrize(
+        "reuse_components_from, expected_error",
+        (
+            (
+                "testmodule:4.3.43:7",
+                'The parameter "reuse_components_from" contains an invalid module identifier',
+            ),
+            (
+                {},
+                'The parameter "reuse_components_from" contains an invalid module identifier',
+            ),
+            (
+                912312312,
+                'The module in the parameter "reuse_components_from" could not be found',
+            ),
+            (
+                7,
+                'The module in the parameter "reuse_components_from" must be in the ready state',
+            )
+        )
+    )
+    @patch("module_build_service.auth.get_user", return_value=user)
+    @patch("module_build_service.scm.SCM")
+    def test_submit_build_reuse_components_from_errors(
+        self, mocked_scm, mocked_get_user, reuse_components_from, expected_error,
+    ):
+        """
+        Test a build submission using an invalid value for the reuse_components_from parameter.
+        """
+        FakeSCM(
+            mocked_scm, "testmodule", "testmodule.yaml", "620ec77321b2ea7b0d67d82992dda3e1d67055b4")
+        rv = self.client.post(
+            "/module-build-service/1/module-builds/",
+            data=json.dumps({
+                "branch": "master",
+                "reuse_components_from": reuse_components_from,
+                "scmurl": (
+                    "https://src.stg.fedoraproject.org/modules/testmodule.git?"
+                    "#68931c90de214d9d13feefbd35246a81b6cb8d49"
+                ),
+            }),
+        )
+        data = json.loads(rv.data)
+        assert rv.status_code == 400
+        assert data["message"] == expected_error
+
+    @patch("module_build_service.auth.get_user", return_value=user)
+    @patch("module_build_service.scm.SCM")
+    @patch(
+        "module_build_service.config.Config.rebuild_strategy_allow_override",
+        new_callable=PropertyMock,
+        return_value=True,
+    )
+    def test_submit_build_reuse_components_rebuild_strategy_all(
+        self, mock_rsao, mocked_scm, mocked_get_user,
+    ):
+        """
+        Test a build submission using reuse_components_from and the rebuild_strategy of all.
+        """
+        FakeSCM(
+            mocked_scm, "testmodule", "testmodule.yaml", "620ec77321b2ea7b0d67d82992dda3e1d67055b4")
+        rv = self.client.post(
+            "/module-build-service/1/module-builds/",
+            data=json.dumps({
+                "branch": "master",
+                "rebuild_strategy": "all",
+                "reuse_components_from": 7,
+                "scmurl": (
+                    "https://src.stg.fedoraproject.org/modules/testmodule.git?"
+                    "#68931c90de214d9d13feefbd35246a81b6cb8d49"
+                ),
+            }),
+        )
+        data = json.loads(rv.data)
+        assert rv.status_code == 400
+        assert data["message"] == (
+            'You cannot specify the parameter "reuse_components_from" when the "rebuild_strategy" '
+            'parameter is set to "all"'
+        )