Move serving_dirs to UserStorySet, delete Page.archive_path (instead using...

Move serving_dirs to UserStorySet, delete Page.archive_path (instead using PageSet.WprFilePathForUserStory).
Update user_story_runner to no longer gate archive-specific logic with instanceof PageSet check.

BUG=439512

Review URL: https://codereview.chromium.org/725133005

Cr-Commit-Position: refs/heads/master@{#308134}

tools/telemetry/telemetry/page/__init__.py

@@ -25,8 +25,12 @@ def _UpdateCredentials(credentials_path):
 class Page(user_story.UserStory):
   def __init__(self, url, page_set=None, base_dir=None, name='',
                credentials_path=None, labels=None, startup_url=''):
-    super(Page, self).__init__(shared_page_state.SharedPageState, name, labels)
     self._url = url
+
+    super(Page, self).__init__(
+        shared_page_state.SharedPageState, name=name, labels=labels,
+        is_local=self._scheme in ['file', 'chrome', 'about'])
+
     self._page_set = page_set
     # Default value of base_dir is the directory of the file that defines the
     # class of this page instance.
@@ -153,11 +157,6 @@ class Page(user_story.UserStory):
     """Returns True iff this URL points to a file."""
     return self._scheme == 'file'
 
-  @property
-  def is_local(self):
-    """Returns True iff this URL is local. This includes chrome:// URLs."""
-    return self._scheme in ['file', 'chrome', 'about']
-
   @property
   def file_path(self):
     """Returns the path of the file, stripping the scheme and query string."""
@@ -200,7 +199,3 @@ class Page(user_story.UserStory):
     all_urls = [p.url.rstrip('/') for p in self.page_set if p.is_file]
     common_prefix = os.path.dirname(os.path.commonprefix(all_urls))
     return self.url[len(common_prefix):].strip('/')
-
-  @property
-  def archive_path(self):
-    return self.page_set.WprFilePathForUserStory(self)

tools/telemetry/telemetry/page/page_set.py

@@ -23,8 +23,6 @@ class PageSet(user_story_set.UserStorySet):
   def __init__(self, file_path=None, archive_data_file='', user_agent_type=None,
                make_javascript_deterministic=True, serving_dirs=None,
                bucket=None):
-    super(PageSet, self).__init__(
-        archive_data_file=archive_data_file, cloud_storage_bucket=bucket)
     # The default value of file_path is location of the file that define this
     # page set instance's class.
     # TODO(chrishenry): Move this logic to user_story_set. Consider passing
@@ -35,14 +33,15 @@ class PageSet(user_story_set.UserStorySet):
       # Turn pyc file into py files if we can
       if file_path.endswith('.pyc') and os.path.exists(file_path[:-1]):
         file_path = file_path[:-1]
-
     self.file_path = file_path
+
+    super(PageSet, self).__init__(
+        archive_data_file=archive_data_file, cloud_storage_bucket=bucket,
+        serving_dirs=serving_dirs)
+
     # These attributes can be set dynamically by the page set.
     self.user_agent_type = user_agent_type
     self.make_javascript_deterministic = make_javascript_deterministic
-    # Convert any relative serving_dirs to absolute paths.
-    self._serving_dirs = set(os.path.realpath(os.path.join(self.base_dir, d))
-                             for d in serving_dirs or [])
 
   @property
   def pages(self):
@@ -70,10 +69,6 @@ class PageSet(user_story_set.UserStorySet):
     else:
       return self.file_path
 
-  @property
-  def serving_dirs(self):
-    return self._serving_dirs
-
   def ReorderPageSet(self, results_file):
     """Reorders this page set based on the results of a past run."""
     page_set_dict = {}

tools/telemetry/telemetry/page/page_unittest.py

@@ -153,3 +153,16 @@ class TestPage(unittest.TestCase):
     self.assertEqual([page_foo, page_baz], page_set_a.pages)
     self.assertEqual([page_bar], page_set_b.pages)
     self.assertIs(page_set_b, page_bar.page_set)
+
+  def testIsLocal(self):
+    p = page.Page('file://foo.html')
+    self.assertTrue(p.is_local)
+
+    p = page.Page('chrome://extensions')
+    self.assertTrue(p.is_local)
+
+    p = page.Page('about:blank')
+    self.assertTrue(p.is_local)
+
+    p = page.Page('http://foo.com')
+    self.assertFalse(p.is_local)

tools/telemetry/telemetry/page/shared_page_state.py

@@ -11,11 +11,11 @@ from telemetry.core import browser_finder_exceptions
 from telemetry.core import browser_info
 from telemetry.core import util
 from telemetry.core import wpr_modes
+from telemetry.core.platform.profiler import profiler_finder
 from telemetry.page import page_test
 from telemetry.user_story import shared_user_story_state
 from telemetry.util import file_handle
 from telemetry.value import skip
-from telemetry.core.platform.profiler import profiler_finder
 
 
 def _PrepareFinderOptions(finder_options, test, page_set):
@@ -111,7 +111,8 @@ class SharedPageState(shared_user_story_state.SharedUserStoryState):
     if self._test.RestartBrowserBeforeEachPage() or page.startup_url:
       self._StopBrowser()
     started_browser = not self.browser
-    self._PrepareWpr(self.platform.network_controller, page.archive_path,
+    self._PrepareWpr(self.platform.network_controller,
+                     page_set.WprFilePathForUserStory(page),
                      page_set.make_javascript_deterministic)
     if self.browser:
       # Set new credential path for browser.

tools/telemetry/telemetry/user_story/__init__.py

@@ -18,14 +18,16 @@ class UserStory(object):
 
   Args:
     shared_user_story_state_class: subclass of
-      telemetry.user_story.shared_user_story_state.SharedUserStoryState.
+        telemetry.user_story.shared_user_story_state.SharedUserStoryState.
     name: string name of this user story that can be used for identifying user
-      story in results output.
+        story in results output.
     labels: A list or set of string labels that are used for filtering. See
-      user_story.user_story_filter for more information.
+        user_story.user_story_filter for more information.
+    is_local: If true, the user story does not require network.
   """
 
-  def __init__(self, shared_user_story_state_class, name='', labels=None):
+  def __init__(self, shared_user_story_state_class, name='', labels=None,
+               is_local=False):
     assert issubclass(shared_user_story_state_class,
                       shared_user_story_state.SharedUserStoryState)
     self._shared_user_story_state_class = shared_user_story_state_class
@@ -40,6 +42,7 @@ class UserStory(object):
     else:
       assert isinstance(labels, set)
     self._labels = labels
+    self._is_local = is_local
 
   @property
   def labels(self):
@@ -78,3 +81,8 @@ class UserStory(object):
       return self.name
     else:
       return self.__class__.__name__
+
+  @property
+  def is_local(self):
+    """Returns True iff this user story does not require network."""
+    return self._is_local

tools/telemetry/telemetry/user_story/android/__init__.py

@@ -6,9 +6,10 @@ from telemetry import user_story
 from telemetry.user_story.android import shared_app_state
 
 class AppStory(user_story.UserStory):
-  def __init__(self, start_intent, name='', labels=None):
+  def __init__(self, start_intent, name='', labels=None, is_local=False):
     super(AppStory, self).__init__(
-        shared_app_state.SharedAppState, name, labels)
+        shared_app_state.SharedAppState, name=name, labels=labels,
+        is_local=is_local)
     self.start_intent = start_intent
 
   def RunPageInteractions(self):

tools/telemetry/telemetry/user_story/user_story_runner.py

@@ -10,12 +10,13 @@ import sys
 import time
 
 from telemetry import decorators
+from telemetry import page as page_module
 from telemetry.core import exceptions
 from telemetry.core import util
 from telemetry.core import wpr_modes
-from telemetry.page import shared_page_state
 from telemetry.page import page_set as page_set_module
 from telemetry.page import page_test
+from telemetry.page import shared_page_state
 from telemetry.page.actions import page_action
 from telemetry.results import results_options
 from telemetry.user_story import user_story_filter
@@ -120,14 +121,14 @@ def _RunUserStoryAndProcessErrorIfNeeded(
 
 
 @decorators.Cache
-def _UpdateUserStoryArchivesIfChanged(page_set):
+def _UpdateUserStoryArchivesIfChanged(user_story_set):
   # Scan every serving directory for .sha1 files
   # and download them from Cloud Storage. Assume all data is public.
-  all_serving_dirs = page_set.serving_dirs.copy()
+  all_serving_dirs = user_story_set.serving_dirs.copy()
   # Add individual page dirs to all serving dirs.
-  for page in page_set:
-    if page.is_file:
-      all_serving_dirs.add(page.serving_dir)
+  for user_story in user_story_set:
+    if isinstance(user_story, page_module.Page) and user_story.is_file:
+      all_serving_dirs.add(user_story.serving_dir)
   # Scan all serving dirs.
   for serving_dir in all_serving_dirs:
     if os.path.splitdrive(serving_dir)[1] == '/':
@@ -138,7 +139,7 @@ def _UpdateUserStoryArchivesIfChanged(page_set):
             os.path.join(dirpath, filename))
         if extension != '.sha1':
           continue
-        cloud_storage.GetIfChanged(path, page_set.bucket)
+        cloud_storage.GetIfChanged(path, user_story_set.bucket)
 
 
 class UserStoryGroup(object):
@@ -196,14 +197,11 @@ def Run(test, user_story_set, expectations, finder_options, results):
   user_stories = _ShuffleAndFilterUserStorySet(user_story_set, finder_options)
 
   if (not finder_options.use_live_sites and
-      finder_options.browser_options.wpr_mode != wpr_modes.WPR_RECORD and
-      # TODO(nednguyen): also handle these logic for user_story_set in next
-      # patch.
-      isinstance(user_story_set, page_set_module.PageSet)):
+      finder_options.browser_options.wpr_mode != wpr_modes.WPR_RECORD):
     _UpdateUserStoryArchivesIfChanged(user_story_set)
     if not _CheckArchives(
         user_story_set.archive_data_file, user_story_set.wpr_archive_info,
-        user_story_set.pages):
+        user_stories):
       return
 
   for user_story in list(user_stories):
@@ -278,18 +276,18 @@ def _ShuffleAndFilterUserStorySet(user_story_set, finder_options):
   return user_stories
 
 
-def _CheckArchives(archive_data_file, wpr_archive_info, pages):
-  """Verifies that all pages are local or have WPR archives.
+def _CheckArchives(archive_data_file, wpr_archive_info, filtered_user_stories):
+  """Verifies that all user stories are local or have WPR archives.
 
   Logs warnings and returns False if any are missing.
   """
-  # Report any problems with the entire page set.
-  if any(not p.is_local for p in pages):
+  # Report any problems with the entire user story set.
+  if any(not user_story.is_local for user_story in filtered_user_stories):
     if not archive_data_file:
-      logging.error('The page set is missing an "archive_data_file" '
+      logging.error('The user story set is missing an "archive_data_file" '
                     'property.\nTo run from live sites pass the flag '
                     '--use-live-sites.\nTo create an archive file add an '
-                    'archive_data_file property to the page set and then '
+                    'archive_data_file property to the user story set and then '
                     'run record_wpr.')
       return False
     if not wpr_archive_info:
@@ -299,35 +297,42 @@ def _CheckArchives(archive_data_file, wpr_archive_info, pages):
                     'or create a new archive using record_wpr.')
       return False
 
-  # Report any problems with individual pages.
-  pages_missing_archive_path = []
-  pages_missing_archive_data = []
-  for page in pages:
-    if not page.is_local and not page.archive_path:
-      pages_missing_archive_path.append(page)
-    elif not page.is_local and not os.path.isfile(page.archive_path):
-      pages_missing_archive_data.append(page)
-  if pages_missing_archive_path:
-    logging.error('The page set archives for some pages do not exist.\n'
-                  'To fix this, record those pages using record_wpr.\n'
-                  'To ignore this warning and run against live sites, '
-                  'pass the flag --use-live-sites.')
+  # Report any problems with individual user story.
+  user_stories_missing_archive_path = []
+  user_stories_missing_archive_data = []
+  for user_story in filtered_user_stories:
+    if not user_story.is_local:
+      archive_path = wpr_archive_info.WprFilePathForUserStory(user_story)
+      if not archive_path:
+        user_stories_missing_archive_path.append(user_story)
+      elif not os.path.isfile(archive_path):
+        user_stories_missing_archive_data.append(user_story)
+  if user_stories_missing_archive_path:
+    logging.error(
+        'The user story set archives for some user stories do not exist.\n'
+        'To fix this, record those user stories using record_wpr.\n'
+        'To ignore this warning and run against live sites, '
+        'pass the flag --use-live-sites.')
+    logging.error(
+        'User stories without archives: %s',
+        ', '.join(user_story.display_name
+                  for user_story in user_stories_missing_archive_path))
+  if user_stories_missing_archive_data:
     logging.error(
-        'Pages without archives: %s',
-        ', '.join(page.display_name for page in pages_missing_archive_path))
-  if pages_missing_archive_data:
-    logging.error('The page set archives for some pages are missing.\n'
-                  'Someone forgot to check them in, uploaded them to the '
-                  'wrong cloud storage bucket, or they were deleted.\n'
-                  'To fix this, record those pages using record_wpr.\n'
-                  'To ignore this warning and run against live sites, '
-                  'pass the flag --use-live-sites.')
+        'The user story set archives for some user stories are missing.\n'
+        'Someone forgot to check them in, uploaded them to the '
+        'wrong cloud storage bucket, or they were deleted.\n'
+        'To fix this, record those user stories using record_wpr.\n'
+        'To ignore this warning and run against live sites, '
+        'pass the flag --use-live-sites.')
     logging.error(
-        'Pages missing archives: %s',
-        ', '.join(page.display_name for page in pages_missing_archive_data))
-  if pages_missing_archive_path or pages_missing_archive_data:
+        'User stories missing archives: %s',
+        ', '.join(user_story.display_name
+                  for user_story in user_stories_missing_archive_data))
+  if user_stories_missing_archive_path or user_stories_missing_archive_data:
     return False
-  # Only run valid pages if no problems with the page set or individual pages.
+  # Only run valid user stories if no problems with the user story set or
+  # individual user stories.
   return True
 
 

tools/telemetry/telemetry/user_story/user_story_runner_unittest.py

@@ -9,7 +9,7 @@ import sys
 from telemetry import benchmark
 from telemetry import user_story
 from telemetry.core import exceptions
-from telemetry.page import page_set
+from telemetry.page import page as page_module
 from telemetry.page import page_test
 from telemetry.page import test_expectations
 from telemetry.results import results_options
@@ -19,6 +19,7 @@ from telemetry.unittest_util import system_stub
 from telemetry.user_story import shared_user_story_state
 from telemetry.user_story import user_story_runner
 from telemetry.user_story import user_story_set
+from telemetry.util import cloud_storage
 from telemetry.util import exception_formatter as exception_formatter_module
 from telemetry.value import scalar
 from telemetry.value import string
@@ -88,6 +89,15 @@ class EmptyMetadataForTest(benchmark.BenchmarkMetadata):
     super(EmptyMetadataForTest, self).__init__('')
 
 
+class DummyLocalUserStory(user_story.UserStory):
+  def __init__(self, shared_user_story_state_class, name=''):
+    super(DummyLocalUserStory, self).__init__(
+        shared_user_story_state_class, name=name)
+
+  @property
+  def is_local(self):
+    return True
+
 def _GetOptionForUnittest():
   options = options_for_unittests.GetCopy()
   options.output_formats = ['none']
@@ -136,10 +146,10 @@ class UserStoryRunnerTest(unittest.TestCase):
 
   def testGetUserStoryGroupsWithSameSharedUserStoryClass(self):
     us = user_story_set.UserStorySet()
-    us.AddUserStory(user_story.UserStory(FooUserStoryState))
-    us.AddUserStory(user_story.UserStory(FooUserStoryState))
-    us.AddUserStory(user_story.UserStory(BarUserStoryState))
-    us.AddUserStory(user_story.UserStory(FooUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FooUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FooUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(BarUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FooUserStoryState))
     story_groups = (
         user_story_runner.GetUserStoryGroupsWithSameSharedUserStoryClass(
             us))
@@ -153,9 +163,9 @@ class UserStoryRunnerTest(unittest.TestCase):
 
   def testSuccefulUserStoryTest(self):
     us = user_story_set.UserStorySet()
-    us.AddUserStory(user_story.UserStory(FooUserStoryState))
-    us.AddUserStory(user_story.UserStory(FooUserStoryState))
-    us.AddUserStory(user_story.UserStory(BarUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FooUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FooUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(BarUserStoryState))
     user_story_runner.Run(
         DummyTest(), us, self.expectations, self.options, self.results)
     self.assertEquals(0, len(self.results.failures))
@@ -184,10 +194,10 @@ class UserStoryRunnerTest(unittest.TestCase):
       def TearDownState(self, _results):
         barz_tear_down_call_counter[0] += 1
 
-    us.AddUserStory(user_story.UserStory(FoozUserStoryState))
-    us.AddUserStory(user_story.UserStory(FoozUserStoryState))
-    us.AddUserStory(user_story.UserStory(BarzUserStoryState))
-    us.AddUserStory(user_story.UserStory(BarzUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FoozUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(FoozUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(BarzUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(BarzUserStoryState))
     user_story_runner.Run(
         DummyTest(), us, self.expectations, self.options, self.results)
     self.assertEquals(0, len(self.results.failures))
@@ -204,7 +214,7 @@ class UserStoryRunnerTest(unittest.TestCase):
       def WillRunUserStory(self, user_storyz):
         raise exceptions.AppCrashException()
 
-    us.AddUserStory(user_story.UserStory(SharedUserStoryThatCausesAppCrash))
+    us.AddUserStory(DummyLocalUserStory(SharedUserStoryThatCausesAppCrash))
     user_story_runner.Run(
         DummyTest(), us, self.expectations, self.options, self.results)
     self.assertEquals(1, len(self.results.failures))
@@ -231,8 +241,8 @@ class UserStoryRunnerTest(unittest.TestCase):
       def ValidateAndMeasurePage(self, page, tab, results):
         pass
 
-    us.AddUserStory(user_story.UserStory(TestSharedUserStoryState))
-    us.AddUserStory(user_story.UserStory(TestSharedUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(TestSharedUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(TestSharedUserStoryState))
     test = Test()
     user_story_runner.Run(
         test, us, self.expectations, self.options, self.results)
@@ -258,8 +268,8 @@ class UserStoryRunnerTest(unittest.TestCase):
       def ValidateAndMeasurePage(self, page, tab, results):
         pass
 
-    us.AddUserStory(user_story.UserStory(TestSharedUserStoryState))
-    us.AddUserStory(user_story.UserStory(TestSharedUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(TestSharedUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(TestSharedUserStoryState))
     test = Test()
     user_story_runner.Run(
         test, us, self.expectations, self.options, self.results)
@@ -269,8 +279,8 @@ class UserStoryRunnerTest(unittest.TestCase):
 
   def testDiscardFirstResult(self):
     us = user_story_set.UserStorySet()
-    us.AddUserStory(user_story.UserStory(TestSharedUserStoryState))
-    us.AddUserStory(user_story.UserStory(TestSharedUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(TestSharedUserStoryState))
+    us.AddUserStory(DummyLocalUserStory(TestSharedUserStoryState))
     class Measurement(page_test.PageTest):
       @property
       def discard_first_result(self):
@@ -324,9 +334,9 @@ class UserStoryRunnerTest(unittest.TestCase):
 
   def testPagesetRepeat(self):
     us = user_story_set.UserStorySet()
-    us.AddUserStory(user_story.UserStory(
+    us.AddUserStory(DummyLocalUserStory(
         TestSharedUserStoryState, name='blank'))
-    us.AddUserStory(user_story.UserStory(
+    us.AddUserStory(DummyLocalUserStory(
         TestSharedUserStoryState, name='green'))
 
     class Measurement(page_test.PageTest):
@@ -361,35 +371,43 @@ class UserStoryRunnerTest(unittest.TestCase):
       sys.stdout = real_stdout
 
   def testCheckArchives(self):
-    ps = page_set.PageSet()
-    ps.AddPageWithDefaultRunNavigate('http://www.testurl.com')
+    uss = user_story_set.UserStorySet()
+    uss.AddUserStory(page_module.Page(
+        'http://www.testurl.com', self, uss.base_dir))
     # Page set missing archive_data_file.
     self.assertFalse(user_story_runner._CheckArchives(
-        ps.archive_data_file, ps.wpr_archive_info, ps.pages))
+        uss.archive_data_file, uss.wpr_archive_info, uss.user_stories))
 
-    ps = page_set.PageSet(archive_data_file='missing_archive_data_file.json')
-    ps.AddPageWithDefaultRunNavigate('http://www.testurl.com')
+    uss = user_story_set.UserStorySet(
+        archive_data_file='missing_archive_data_file.json')
+    uss.AddUserStory(page_module.Page(
+        'http://www.testurl.com', self, uss.base_dir))
     # Page set missing json file specified in archive_data_file.
     self.assertFalse(user_story_runner._CheckArchives(
-       ps.archive_data_file, ps.wpr_archive_info, ps.pages))
+        uss.archive_data_file, uss.wpr_archive_info, uss.user_stories))
 
-    ps = page_set.PageSet(archive_data_file='../../unittest_data/test.json',
-                          bucket=page_set.PUBLIC_BUCKET)
-    ps.AddPageWithDefaultRunNavigate('http://www.testurl.com')
+    uss = user_story_set.UserStorySet(
+        archive_data_file='../../unittest_data/test.json',
+        cloud_storage_bucket=cloud_storage.PUBLIC_BUCKET)
+    uss.AddUserStory(page_module.Page(
+        'http://www.testurl.com', self, uss.base_dir))
     # Page set with valid archive_data_file.
     self.assertTrue(user_story_runner._CheckArchives(
-        ps.archive_data_file, ps.wpr_archive_info, ps.pages))
-    ps.AddPageWithDefaultRunNavigate('http://www.google.com')
+        uss.archive_data_file, uss.wpr_archive_info, uss.user_stories))
+    uss.AddUserStory(page_module.Page(
+        'http://www.google.com', self, uss.base_dir))
     # Page set with an archive_data_file which exists but is missing a page.
     self.assertFalse(user_story_runner._CheckArchives(
-        ps.archive_data_file, ps.wpr_archive_info, ps.pages))
+        uss.archive_data_file, uss.wpr_archive_info, uss.user_stories))
 
-    ps = page_set.PageSet(
+    uss = user_story_set.UserStorySet(
         archive_data_file='../../unittest_data/test_missing_wpr_file.json',
-        bucket=page_set.PUBLIC_BUCKET)
-    ps.AddPageWithDefaultRunNavigate('http://www.testurl.com')
-    ps.AddPageWithDefaultRunNavigate('http://www.google.com')
+        cloud_storage_bucket=cloud_storage.PUBLIC_BUCKET)
+    uss.AddUserStory(page_module.Page(
+        'http://www.testurl.com', self, uss.base_dir))
+    uss.AddUserStory(page_module.Page(
+        'http://www.google.com', self, uss.base_dir))
     # Page set with an archive_data_file which exists and contains all pages
     # but fails to find a wpr file.
     self.assertFalse(user_story_runner._CheckArchives(
-        ps.archive_data_file, ps.wpr_archive_info, ps.pages))
+        uss.archive_data_file, uss.wpr_archive_info, uss.user_stories))

tools/telemetry/telemetry/user_story/user_story_set.py

@@ -16,7 +16,8 @@ class UserStorySet(object):
   AddUserStory for each UserStory..
   """
 
-  def __init__(self, archive_data_file='', cloud_storage_bucket=None):
+  def __init__(self, archive_data_file='', cloud_storage_bucket=None,
+               serving_dirs=None):
     """Creates a new UserStorySet.
 
     Args:
@@ -33,6 +34,9 @@ class UserStorySet(object):
     archive_info.AssertValidCloudStorageBucket(cloud_storage_bucket)
     self._cloud_storage_bucket = cloud_storage_bucket
     self._base_dir = os.path.dirname(inspect.getfile(self.__class__))
+    # Convert any relative serving_dirs to absolute paths.
+    self._serving_dirs = set(os.path.realpath(os.path.join(self.base_dir, d))
+                             for d in serving_dirs or [])
 
   @property
   def base_dir(self):
@@ -42,6 +46,10 @@ class UserStorySet(object):
     """
     return self._base_dir
 
+  @property
+  def serving_dirs(self):
+    return self._serving_dirs
+
   @property
   def archive_data_file(self):
     return self._archive_data_file
@@ -87,6 +95,15 @@ class UserStorySet(object):
     pass
 
   def WprFilePathForUserStory(self, story):
+    """Convenient function to retrive WPR archive file path.
+
+    Args:
+      user_story: The UserStory to lookup.
+
+    Returns:
+      The WPR archive file path for the given UserStory, if found.
+      Otherwise, return None.
+    """
     if not self.wpr_archive_info:
       return None
     return self.wpr_archive_info.WprFilePathForUserStory(story)