Merge lp:~michael.nelson/launchpad/delegate-to-buildfarmjob into lp:launchpad

[Michael Nelson]

Switch BuildFarmJob from an inherited mix-in to a delegated object in preparation for the build generalisation work.

This branch switches BuildFarmJob from an inherited mix-in to a delegated object, in preparation for the build generalisation work (where BuildFarmJob will become a concrete Storm class).

While at it, I used the opportunity to merge two interfaces specific to the build farm queue scheduling into existing interfaces (see bug 562252).

There is no demo url, this is just an implementation detail.

Test command:
bin/test -vvt test_translationtemplatesbuildjob -t test_buildqueue -t doc/buildfarmjob.txt

Pre-implementation:
This is part of the LEP https://dev.launchpad.net/LEP/GeneralBuildHistories which has been discussed with jml. The reason for the delegation rather than inheritance is that BuildFarmJob will become a concrete Storm class.

[Brad Crittenden (bac)]

Hi Michael,

This branch looks good.

Since _set_build_farm_job() is a method which is intended to be overridden please provide a docstring for it.

Also, our coding guidelines state the docstring must be a single line followed by a longer explanation if needed. It is quite Draconian and leads to some haiku-like challenges but please see if you can adhere to the rule.

review: Approve (code)

=== modified file 'lib/lp/buildmaster/doc/buildfarmjob.txt'
--- lib/lp/buildmaster/doc/buildfarmjob.txt	2010-01-14 09:55:06 +0000
+++ lib/lp/buildmaster/doc/buildfarmjob.txt	2010-04-21 11:53:24 +0000
@@ -1,20 +1,43 @@
-= BuildFarmJob =
+BuildFarmJob
+============
 
     >>> from lp.buildmaster.interfaces.buildfarmjob import IBuildFarmJob
-    >>> from lp.buildmaster.model.buildfarmjob import BuildFarmJob
+    >>> from lp.buildmaster.model.buildfarmjob import (
+    ...     BuildFarmJob, BuildFarmJobDerived)
 
 BuildFarmJob provides a basic implementation of IBuildFarmJob.  The
-specific build farm job classes should inherit from it.
+specific build farm job classes will automatically delegate to
+BuildFarmJob by inheriting BuildFarmJobDerived.
 
     >>> buildfarmjob = BuildFarmJob()
-    >>> verifyObject(IBuildFarmJob, buildfarmjob) 
+    >>> verifyObject(IBuildFarmJob, buildfarmjob)
     True
 
-As a class, it also provides ISpecificBuildFarmJobClass so that
-BuildQueue can find the instance of a specific build-farm job
-implementation associated with a given Job instance.
+The BuildFarmJob class does not (yet) do a lot itself, other than
+providing default implementations for its methods.
+
+    >>> print buildfarmjob.getLogFileName()
+    buildlog.txt
+
+    >>> buildfarmjob.getName()
+    Traceback (most recent call last):
+    ...
+    NotImplementedError
+
+
+BuildFarmJobDerived
+===================
+
+BuildFarmJobDerived exists to encapsulate the functionality required
+by classes delegating IBuildFarmJob.
 
     >>> from lp.buildmaster.interfaces.buildfarmjob import (
-    ...     ISpecificBuildFarmJobClass)
-    >>> verifyObject(ISpecificBuildFarmJobClass, BuildFarmJob)
+    ...     IBuildFarmJobDerived)
+    >>> verifyObject(IBuildFarmJobDerived, BuildFarmJobDerived())
     True
+
+This class also includes the getByJob() class method used to find the
+instance of a specific build-farm job implementation associated with a
+given Job instance which must be called in the context of a concrete
+derived class. See lp.buildmaster.tests.test_buildqueue for examples.
+
 
=== modified file 'lib/lp/buildmaster/interfaces/buildfarmbranchjob.py'
--- lib/lp/buildmaster/interfaces/buildfarmbranchjob.py	2010-03-17 05:58:22 +0000
+++ lib/lp/buildmaster/interfaces/buildfarmbranchjob.py	2010-04-21 11:53:24 +0000
@@ -8,11 +8,10 @@
     'IBuildFarmBranchJob'
     ]
 
-from lp.buildmaster.interfaces.buildfarmjob import IBuildFarmJob
 from lp.code.interfaces.branchjob import IBranchJob
 
 
-class IBuildFarmBranchJob(IBuildFarmJob, IBranchJob):
+class IBuildFarmBranchJob(IBranchJob):
     """An `IBuildFarmJob` that's also an `IBranchJob`.
 
     Use this interface for `IBuildFarmJob` implementations that do not
 
=== modified file 'lib/lp/buildmaster/interfaces/buildfarmjob.py'
--- lib/lp/buildmaster/interfaces/buildfarmjob.py	2010-04-12 05:52:01 +0000
+++ lib/lp/buildmaster/interfaces/buildfarmjob.py	2010-04-21 11:53:24 +0000
@@ -9,8 +9,7 @@
 
 __all__ = [
     'IBuildFarmJob',
-    'IBuildFarmCandidateJobSelection',
-    'ISpecificBuildFarmJobClass',
+    'IBuildFarmJobDerived',
     'BuildFarmJobType',
     ]
 
@@ -57,16 +56,6 @@
 class IBuildFarmJob(Interface):
     """Operations that jobs for the build farm must implement."""
 
-    def generateSlaveBuildCookie():
-        """Produce a cookie for the slave as a token of the job it's doing.
-
-        The cookie need not be unique, but should be hard for a
-        compromised slave to guess.
-
-        :return: a hard-to-guess ASCII string that can be reproduced
-            accurately based on this job's properties.
-        """
-
     def score():
         """Calculate a job score appropriate for the job type in question."""
 
@@ -101,11 +90,10 @@
             "return None."))
 
 
-class ISpecificBuildFarmJobClass(Interface):
-    """Class interface provided by `IBuildFarmJob` classes.
+class IBuildFarmJobDerived(Interface):
+    """Common functionality required by classes delegating IBuildFarmJob.
 
-    Used by the `BuildQueue` to find the specific build-farm job objects
-    it needs to dispatch to builders.
+    An implementation of this class must setup the necessary delagation.
     """
 
     def getByJob(job):
@@ -115,15 +103,6 @@
         has an entry associated with `job`.
         """
 
-
-class IBuildFarmCandidateJobSelection(Interface):
-    """Operations for refining candidate job selection (optional).
-
-    Job type classes that do *not* need to refine candidate job selection may
-    be derived from `BuildFarmJob` which provides a base implementation of
-    this interface.
-    """
-
     def addCandidateSelectionCriteria(processor, virtualized):
         """Provide a sub-query to refine the candidate job selection.
 
@@ -159,3 +138,14 @@
         :return: True if the candidate job should be dispatched
             to a builder, False otherwise.
         """
+
+    def generateSlaveBuildCookie():
+        """Produce a cookie for the slave as a token of the job it's doing.
+
+        The cookie need not be unique, but should be hard for a
+        compromised slave to guess.
+
+        :return: a hard-to-guess ASCII string that can be reproduced
+            accurately based on this job's properties.
+        """
+
 
=== modified file 'lib/lp/buildmaster/model/buildfarmjob.py'
--- lib/lp/buildmaster/model/buildfarmjob.py	2010-04-12 05:52:01 +0000
+++ lib/lp/buildmaster/model/buildfarmjob.py	2010-04-21 11:53:24 +0000
@@ -2,48 +2,31 @@
 # GNU Affero General Public License version 3 (see the file LICENSE).
 
 __metaclass__ = type
-__all__ = ['BuildFarmJob']
-
+__all__ = [
+    'BuildFarmJob',
+    'BuildFarmJobDerived',
+    ]
+
+
+from lazr.delegates import delegates
 
 import hashlib
 
 from zope.component import getUtility
-from zope.interface import classProvides, implements
+from zope.interface import implements
 from zope.security.proxy import removeSecurityProxy
 
 from canonical.launchpad.webapp.interfaces import (
     DEFAULT_FLAVOR, IStoreSelector, MAIN_STORE)
+
 from lp.buildmaster.interfaces.buildfarmjob import (
-    IBuildFarmJob, IBuildFarmCandidateJobSelection,
-    ISpecificBuildFarmJobClass)
+    IBuildFarmJob, IBuildFarmJobDerived)
 from lp.buildmaster.interfaces.buildqueue import IBuildQueueSet
 
 
 class BuildFarmJob:
-    """Mix-in class for `IBuildFarmJob` implementations."""
+    """A base implementation for `IBuildFarmJob` classes."""
     implements(IBuildFarmJob)
-    classProvides(
-        IBuildFarmCandidateJobSelection, ISpecificBuildFarmJobClass)
-
-    def generateSlaveBuildCookie(self):
-        """See `IBuildFarmJob`."""
-        buildqueue = getUtility(IBuildQueueSet).getByJob(self.job)
-
-        if buildqueue.processor is None:
-            processor = '*'
-        else:
-            processor = repr(buildqueue.processor.id)
-
-        contents = ';'.join([
-            repr(removeSecurityProxy(self.job).id),
-            self.job.date_created.isoformat(),
-            repr(buildqueue.id),
-            buildqueue.job_type.name,
-            processor,
-            self.getName(),
-            ])
-
-        return hashlib.sha1(contents).hexdigest()
 
     def score(self):
         """See `IBuildFarmJob`."""
@@ -83,22 +66,66 @@
         """See `IBuildFarmJob`."""
         return None
 
-    @staticmethod
-    def addCandidateSelectionCriteria(processor, virtualized):
-        """See `IBuildFarmCandidateJobSelection`."""
-        return ('')
+
+class BuildFarmJobDerived:
+    """See `IBuildFarmJobDerived`."""
+    implements(IBuildFarmJobDerived)
+    delegates(IBuildFarmJob, context='_build_farm_job')
+
+    def __init__(self, *args, **kwargs):
+        """Ensure the instance to which we delegate is set on creation."""
+        self._set_build_farm_job()
+        super(BuildFarmJobDerived, self).__init__(*args, **kwargs)
+
+    def __storm_loaded__(self):
+        """Set the attribute for our IBuildFarmJob delegation.
+
+        This is needed here as __init__() is not called when a storm object
+        is loaded from the database.
+        """
+        self._set_build_farm_job()
+
+    def _set_build_farm_job(self):
+        """Set the build farm job to which we will delegate.
+
+        Sub-classes can override as required.
+        """
+        self._build_farm_job = BuildFarmJob()
 
     @classmethod
     def getByJob(cls, job):
-        """See `ISpecificBuildFarmJobClass`.
-        This base implementation should work for most build farm job
-        types, but some need to override it.
-        """
+        """See `IBuildFarmJobDerived`."""
         store = getUtility(IStoreSelector).get(MAIN_STORE, DEFAULT_FLAVOR)
         return store.find(cls, cls.job == job).one()
 
     @staticmethod
+    def addCandidateSelectionCriteria(processor, virtualized):
+        """See `IBuildFarmJobDerived`."""
+        return ('')
+
+    @staticmethod
     def postprocessCandidate(job, logger):
-        """See `IBuildFarmCandidateJobSelection`."""
+        """See `IBuildFarmJobDerived`."""
         return True
 
+    def generateSlaveBuildCookie(self):
+        """See `IBuildFarmJobDerived`."""
+        buildqueue = getUtility(IBuildQueueSet).getByJob(self.job)
+
+        if buildqueue.processor is None:
+            processor = '*'
+        else:
+            processor = repr(buildqueue.processor.id)
+
+        contents = ';'.join([
+            repr(removeSecurityProxy(self.job).id),
+            self.job.date_created.isoformat(),
+            repr(buildqueue.id),
+            buildqueue.job_type.name,
+            processor,
+            self.getName(),
+            ])
+
+        return hashlib.sha1(contents).hexdigest()
+
+
 
=== modified file 'lib/lp/buildmaster/model/packagebuildfarmjob.py'
--- lib/lp/buildmaster/model/packagebuildfarmjob.py	2010-03-25 14:38:25 +0000
+++ lib/lp/buildmaster/model/packagebuildfarmjob.py	2010-04-21 11:53:24 +0000
@@ -2,17 +2,32 @@
 # GNU Affero General Public License version 3 (see the file LICENSE).
 
 __metaclass__ = type
-__all__ = ['PackageBuildFarmJob']
+__all__ = [
+    'PackageBuildFarmJob',
+    'PackageBuildFarmJobDerived',
+    ]
 
 
 from canonical.database.constants import UTC_NOW
 
 from lp.buildmaster.interfaces.buildbase import BuildStatus
-from lp.buildmaster.model.buildfarmjob import BuildFarmJob
+from lp.buildmaster.model.buildfarmjob import (
+    BuildFarmJob, BuildFarmJobDerived)
 
 
 class PackageBuildFarmJob(BuildFarmJob):
-    """Mix-in class for `IBuildFarmJob` implementations for package builds."""
+    """An implementation of `IBuildFarmJob` for package builds."""
+
+    def __init__(self, build):
+        """Store the build for this package build farm job.
+
+        XXX 2010-04-12 michael.nelson bug=536700
+        The build param will no longer be necessary once BuildFarmJob is
+        itself a concrete class. This class (PackageBuildFarmJob)
+        will also be renamed PackageBuild and turned into a concrete class.
+        """
+        super(PackageBuildFarmJob, self).__init__()
+        self.build = build
 
     def getTitle(self):
         """See `IBuildFarmJob`."""
@@ -32,3 +47,14 @@
     def jobAborted(self):
         """See `IBuildFarmJob`."""
         self.build.buildstate = BuildStatus.NEEDSBUILD
+
+
+class PackageBuildFarmJobDerived(BuildFarmJobDerived):
+    """Override the base delegate.
+
+    Ensure that we use a build farm job specific to packages.
+    """
+    def _set_build_farm_job(self):
+        self._build_farm_job = PackageBuildFarmJob(self.build)
+
+
 
=== modified file 'lib/lp/buildmaster/tests/test_buildqueue.py'
--- lib/lp/buildmaster/tests/test_buildqueue.py	2010-04-12 08:29:02 +0000
+++ lib/lp/buildmaster/tests/test_buildqueue.py	2010-04-21 11:53:24 +0000
@@ -8,7 +8,8 @@
 from pytz import utc
 from unittest import TestLoader
 
-from zope.component import getUtility
+from zope import component
+from zope.component import getGlobalSiteManager, getUtility
 from zope.interface.verify import verifyObject
 
 from canonical.launchpad.webapp.interfaces import (
@@ -17,10 +18,11 @@
 
 from lp.buildmaster.interfaces.buildbase import BuildStatus
 from lp.buildmaster.interfaces.builder import IBuilderSet
-from lp.buildmaster.interfaces.buildfarmjob import BuildFarmJobType
+from lp.buildmaster.interfaces.buildfarmjob import (
+    BuildFarmJobType, IBuildFarmJob)
 from lp.buildmaster.interfaces.buildqueue import IBuildQueueSet
 from lp.buildmaster.model.builder import specific_job_classes
-from lp.buildmaster.model.buildfarmjob import BuildFarmJob
+from lp.buildmaster.model.buildfarmjob import BuildFarmJobDerived
 from lp.buildmaster.model.buildqueue import BuildQueue, get_builder_data
 from lp.services.job.model.job import Job
 from lp.soyuz.interfaces.archive import ArchivePurpose
@@ -885,9 +887,7 @@
 
     def test_OtherTypeClasses(self):
         """Other job type classes are picked up as well."""
-        from zope import component
-        from lp.buildmaster.interfaces.buildfarmjob import IBuildFarmJob
-        class FakeBranchBuild(BuildFarmJob):
+        class FakeBranchBuild(BuildFarmJobDerived):
             pass
 
         _build, bq = find_job(self, 'gedit')
@@ -896,17 +896,24 @@
         self.assertTrue(
             specific_job_classes().get(BuildFarmJobType.BRANCHBUILD) is None)
 
-        # Pretend that our `FakeBranchBuild` class implements the
-        # `IBuildFarmJob` interface.
-        component.provideUtility(
-            FakeBranchBuild, IBuildFarmJob, 'BRANCHBUILD')
-
-        # Now we should see the `FakeBranchBuild` class "registered" in the
-        # `specific_job_classes` dictionary under the 'BRANCHBUILD' key.
-        self.assertEqual(
-            specific_job_classes()[BuildFarmJobType.BRANCHBUILD],
-            FakeBranchBuild)
-
+        try:
+            # Pretend that our `FakeBranchBuild` class implements the
+            # `IBuildFarmJob` interface.
+            component.provideUtility(
+                FakeBranchBuild, IBuildFarmJob, 'BRANCHBUILD')
+
+            # Now we should see the `FakeBranchBuild` class "registered"
+            # in the `specific_job_classes` dictionary under the
+            # 'BRANCHBUILD' key.
+            self.assertEqual(
+                specific_job_classes()[BuildFarmJobType.BRANCHBUILD],
+                FakeBranchBuild)
+        finally:
+            # Just de-register the utility so we don't affect other
+            # tests.
+            site_manager = getGlobalSiteManager()
+            site_manager.unregisterUtility(
+                FakeBranchBuild, IBuildFarmJob, 'BRANCHBUILD')
 
 class TestPlatformData(TestCaseWithFactory):
     """Tests covering the processor/virtualized properties."""
 
=== modified file 'lib/lp/code/configure.zcml'
--- lib/lp/code/configure.zcml	2010-04-20 06:42:29 +0000
+++ lib/lp/code/configure.zcml	2010-04-21 11:53:24 +0000
@@ -31,7 +31,7 @@
 
   <class class="lp.code.model.codereviewvote.CodeReviewVoteReference">
     <allow interface="lp.code.interfaces.codereviewvote.ICodeReviewVoteReferencePublic"/>
-    <require 
+    <require
         permission="launchpad.Edit"
         interface="lp.code.interfaces.codereviewvote.ICodeReviewVoteReferenceEdit"/>
   </class>
@@ -988,6 +988,7 @@
   <class
      class="lp.code.model.sourcepackagerecipebuild.SourcePackageRecipeBuildJob">
     <allow interface="lp.code.interfaces.sourcepackagerecipebuild.ISourcePackageRecipeBuildJob"/>
+    <allow interface="lp.buildmaster.interfaces.buildfarmjob.IBuildFarmJobDerived"/>
   </class>
 
   <securedutility
 
=== modified file 'lib/lp/code/model/sourcepackagerecipebuild.py'
--- lib/lp/code/model/sourcepackagerecipebuild.py	2010-04-19 03:36:27 +0000
+++ lib/lp/code/model/sourcepackagerecipebuild.py	2010-04-21 11:53:24 +0000
@@ -27,7 +27,8 @@
 from lp.buildmaster.interfaces.buildfarmjob import BuildFarmJobType
 from lp.buildmaster.model.buildbase import BuildBase
 from lp.buildmaster.model.buildqueue import BuildQueue
-from lp.buildmaster.model.packagebuildfarmjob import PackageBuildFarmJob
+from lp.buildmaster.model.packagebuildfarmjob import (
+    PackageBuildFarmJobDerived)
 from lp.code.interfaces.sourcepackagerecipebuild import (
     ISourcePackageRecipeBuildJob, ISourcePackageRecipeBuildJobSource,
     ISourcePackageRecipeBuild, ISourcePackageRecipeBuildSource)
@@ -198,7 +199,7 @@
         return
 
 
-class SourcePackageRecipeBuildJob(PackageBuildFarmJob, Storm):
+class SourcePackageRecipeBuildJob(PackageBuildFarmJobDerived, Storm):
     classProvides(ISourcePackageRecipeBuildJobSource)
     implements(ISourcePackageRecipeBuildJob)
 
@@ -217,15 +218,15 @@
     virtualized = True
 
     def __init__(self, build, job):
-        super(SourcePackageRecipeBuildJob, self).__init__()
         self.build = build
         self.job = job
+        super(SourcePackageRecipeBuildJob, self).__init__()
 
     @classmethod
     def new(cls, build, job):
         """See `ISourcePackageRecipeBuildJobSource`."""
         specific_job = cls(build, job)
-        store = IMasterStore(SourcePackageRecipeBuildJob)
+        store = IMasterStore(cls)
         store.add(specific_job)
         return specific_job
 
 
=== modified file 'lib/lp/soyuz/configure.zcml'
--- lib/lp/soyuz/configure.zcml	2010-04-12 11:37:48 +0000
+++ lib/lp/soyuz/configure.zcml	2010-04-21 11:53:24 +0000
@@ -848,6 +848,8 @@
         class="lp.soyuz.model.buildpackagejob.BuildPackageJob">
         <allow
             interface="lp.soyuz.interfaces.buildpackagejob.IBuildPackageJob"/>
+        <allow
+            interface="lp.buildmaster.interfaces.buildfarmjob.IBuildFarmJobDerived"/>
     </class>
     <!--
         The registration below is used to discover all build farm job classes
 
=== modified file 'lib/lp/soyuz/model/binarypackagebuild.py'
--- lib/lp/soyuz/model/binarypackagebuild.py	2010-04-09 15:46:09 +0000
+++ lib/lp/soyuz/model/binarypackagebuild.py	2010-04-21 11:53:24 +0000
@@ -313,9 +313,7 @@
         store = Store.of(self)
         job = Job()
         store.add(job)
-        specific_job = BuildPackageJob()
-        specific_job.build = self.id
-        specific_job.job = job.id
+        specific_job = BuildPackageJob(build=self, job=job)
         store.add(specific_job)
         return specific_job
 
 
=== modified file 'lib/lp/soyuz/model/buildpackagejob.py'
--- lib/lp/soyuz/model/buildpackagejob.py	2010-04-12 11:37:48 +0000
+++ lib/lp/soyuz/model/buildpackagejob.py	2010-04-21 11:53:24 +0000
@@ -12,13 +12,14 @@
 
 from storm.locals import Int, Reference, Storm
 
+from zope.component import getUtility
 from zope.interface import implements
-from zope.component import getUtility
 
 from canonical.database.sqlbase import sqlvalues
 
 from lp.buildmaster.interfaces.buildbase import BuildStatus
-from lp.buildmaster.model.packagebuildfarmjob import PackageBuildFarmJob
+from lp.buildmaster.model.packagebuildfarmjob import (
+    PackageBuildFarmJobDerived)
 from lp.registry.interfaces.sourcepackage import SourcePackageUrgency
 from lp.registry.interfaces.pocket import PackagePublishingPocket
 from lp.soyuz.interfaces.archive import ArchivePurpose
@@ -27,7 +28,7 @@
 from lp.soyuz.interfaces.publishing import PackagePublishingStatus
 
 
-class BuildPackageJob(PackageBuildFarmJob, Storm):
+class BuildPackageJob(PackageBuildFarmJobDerived, Storm):
     """See `IBuildPackageJob`."""
     implements(IBuildPackageJob)
 
@@ -40,6 +41,11 @@
     build_id = Int(name='build', allow_none=False)
     build = Reference(build_id, 'BinaryPackageBuild.id')
 
+    def __init__(self, build, job):
+        """ Setup the IBuildFarmJob delegation when new items are created."""
+        self.build, self.job = build, job
+        super(BuildPackageJob, self).__init__()
+
     def score(self):
         """See `IBuildPackageJob`."""
         score_pocketname = {
@@ -166,7 +172,7 @@
 
     @staticmethod
     def addCandidateSelectionCriteria(processor, virtualized):
-        """See `IBuildFarmCandidateJobSelection`."""
+        """See `IBuildFarmJob`."""
         # Avoiding circular import.
         from lp.buildmaster.model.builder import Builder
 
@@ -236,7 +242,7 @@
 
     @staticmethod
     def postprocessCandidate(job, logger):
-        """See `IBuildFarmCandidateJobSelection`."""
+        """See `IBuildFarmJob`."""
         # Mark build records targeted to old source versions as SUPERSEDED
         # and build records target to SECURITY pocket as FAILEDTOBUILD.
         # Builds in those situation should not be built because they will
 
=== modified file 'lib/lp/soyuz/tests/test_buildpackagejob.py'
--- lib/lp/soyuz/tests/test_buildpackagejob.py	2010-04-12 08:29:02 +0000
+++ lib/lp/soyuz/tests/test_buildpackagejob.py	2010-04-21 11:53:24 +0000
@@ -13,7 +13,10 @@
 
 from lp.buildmaster.interfaces.buildbase import BuildStatus
 from lp.buildmaster.interfaces.builder import IBuilderSet
+from lp.buildmaster.interfaces.buildfarmjob import (
+    IBuildFarmJob, IBuildFarmJobDerived)
 from lp.soyuz.interfaces.archive import ArchivePurpose
+from lp.soyuz.interfaces.buildpackagejob import IBuildPackageJob
 from lp.soyuz.interfaces.publishing import PackagePublishingStatus
 from lp.soyuz.model.binarypackagebuild import BinaryPackageBuild
 from lp.soyuz.model.processor import ProcessorFamilySet
@@ -225,3 +228,13 @@
         # Test that BuildPackageJob returns the title of the build.
         build, bq = find_job(self, 'gcc', '386')
         self.assertEqual(bq.specific_job.getTitle(), build.title)
+
+    def test_providesInterfaces(self):
+        # Ensure that a BuildPackageJob generates an appropriate cookie.
+        build, bq = find_job(self, 'gcc', '386')
+        build_farm_job = bq.specific_job
+        self.assertProvides(build_farm_job, IBuildPackageJob)
+        self.assertProvides(build_farm_job, IBuildFarmJob)
+        self.assertProvides(build_farm_job, IBuildFarmJobDerived)
+
+
 
=== modified file 'lib/lp/translations/configure.zcml'
--- lib/lp/translations/configure.zcml	2010-02-17 11:19:42 +0000
+++ lib/lp/translations/configure.zcml	2010-04-21 11:53:24 +0000
@@ -579,6 +579,8 @@
             interface="lp.code.interfaces.branchjob.IBranchJob"/>
         <allow
             interface="lp.buildmaster.interfaces.buildfarmjob.IBuildFarmJob"/>
+        <allow
+            interface="lp.buildmaster.interfaces.buildfarmjob.IBuildFarmJobDerived"/>
     </class>
     <securedutility
         component="lp.translations.model.translationtemplatesbuildjob.TranslationTemplatesBuildJob"
 
=== modified file 'lib/lp/translations/model/translationtemplatesbuildjob.py'
--- lib/lp/translations/model/translationtemplatesbuildjob.py	2010-03-18 12:25:36 +0000
+++ lib/lp/translations/model/translationtemplatesbuildjob.py	2010-04-21 11:53:24 +0000
@@ -18,10 +18,9 @@
 from canonical.launchpad.webapp.interfaces import (
     DEFAULT_FLAVOR, IStoreSelector, MAIN_STORE, MASTER_FLAVOR)
 
-from lp.buildmaster.interfaces.buildfarmjob import (
-    BuildFarmJobType, ISpecificBuildFarmJobClass)
-from lp.buildmaster.model.buildfarmjob import BuildFarmJob
+from lp.buildmaster.interfaces.buildfarmjob import BuildFarmJobType
 from lp.buildmaster.interfaces.buildqueue import IBuildQueueSet
+from lp.buildmaster.model.buildfarmjob import BuildFarmJobDerived
 from lp.buildmaster.model.buildqueue import BuildQueue
 from lp.code.interfaces.branchjob import IRosettaUploadJobSource
 from lp.buildmaster.interfaces.buildfarmbranchjob import IBuildFarmBranchJob
@@ -31,17 +30,15 @@
 from lp.translations.pottery.detect_intltool import is_intltool_structure
 
 
-class TranslationTemplatesBuildJob(BranchJobDerived, BuildFarmJob):
+class TranslationTemplatesBuildJob(BuildFarmJobDerived, BranchJobDerived):
     """An `IBuildFarmJob` implementation that generates templates.
 
     Implementation-wise, this is actually a `BranchJob`.
     """
     implements(IBuildFarmBranchJob)
-
     class_job_type = BranchJobType.TRANSLATION_TEMPLATES_BUILD
 
-    classProvides(
-        ISpecificBuildFarmJobClass, ITranslationTemplatesBuildJobSource)
+    classProvides(ITranslationTemplatesBuildJobSource)
 
     duration_estimate = timedelta(seconds=10)
 
@@ -110,7 +107,6 @@
             branch, BranchJobType.TRANSLATION_TEMPLATES_BUILD, metadata)
         store.add(branch_job)
         specific_job = TranslationTemplatesBuildJob(branch_job)
-
         duration_estimate = cls.duration_estimate
         build_queue_entry = BuildQueue(
             estimated_duration=duration_estimate,
@@ -133,7 +129,10 @@
 
     @classmethod
     def getByJob(cls, job):
-        """See `ISpecificBuildFarmJobClass`."""
+        """See `IBuildFarmJobDerived`.
+
+        Overridden here to search via a BranchJob, rather than a Job.
+        """
         store = getUtility(IStoreSelector).get(MAIN_STORE, DEFAULT_FLAVOR)
         branch_job = store.find(BranchJob, BranchJob.job == job).one()
         if branch_job is None:
 
=== modified file 'lib/lp/translations/tests/test_translationtemplatesbuildjob.py'
--- lib/lp/translations/tests/test_translationtemplatesbuildjob.py	2010-03-06 00:21:57 +0000
+++ lib/lp/translations/tests/test_translationtemplatesbuildjob.py	2010-04-21 11:53:24 +0000
@@ -19,7 +19,7 @@
 from lp.testing import TestCaseWithFactory
 
 from lp.buildmaster.interfaces.buildfarmjob import (
-    IBuildFarmJob, ISpecificBuildFarmJobClass)
+    IBuildFarmJob, IBuildFarmJobDerived)
 from lp.buildmaster.interfaces.buildfarmjobbehavior import (
     IBuildFarmJobBehavior)
 from lp.buildmaster.interfaces.buildqueue import IBuildQueueSet
@@ -54,14 +54,12 @@
         self.specific_job = self.jobset.create(self.branch)
 
     def test_new_TranslationTemplatesBuildJob(self):
-        # TranslationTemplateBuildJob implements IBuildFarmJob and
-        # IBranchJob.
+        # TranslationTemplateBuildJob implements IBuildFarmJob,
+        # IBuildFarmJobDerived, and IBranchJob.
         verifyObject(IBranchJob, self.specific_job)
+        verifyObject(IBuildFarmJobDerived, self.specific_job)
         verifyObject(IBuildFarmJob, self.specific_job)
 
-        # The class also implements ISpecificBuildFarmJobClass.
-        verifyObject(ISpecificBuildFarmJobClass, TranslationTemplatesBuildJob)
-
         # Each of these jobs knows the branch it will operate on.
         self.assertEqual(self.branch, self.specific_job.branch)
 
@@ -91,7 +89,7 @@
         self.assertNotEqual(self.specific_job.getName(), other_job.getName())
 
     def test_getTitle(self):
-        other_job = self.jobset.create(self.branch)
+        self.jobset.create(self.branch)
         self.assertEqual(
             '%s translation templates build' % self.branch.bzr_identity,
             self.specific_job.getTitle())
@@ -191,7 +189,7 @@
         # branch, generatesTemplates returns False.
         branch = self._makeTranslationBranch()
         self.assertFalse(self.jobsource.generatesTemplates(branch))
-    
+
     def test_branch_not_used(self):
         # We don't generate templates branches not attached to series.
         branch = self._makeTranslationBranch(fake_pottery_compatible=True)