Adds extra logging to telemetry in hope it helps diagnose issue 351143

tools/telemetry/telemetry/page/page_set_archive_info.py

Index: tools/telemetry/telemetry/page/page_set_archive_info.py
diff --git a/tools/telemetry/telemetry/page/page_set_archive_info.py b/tools/telemetry/telemetry/page/page_set_archive_info.py
index c9a7959f589e752768d820f9263055dca7359dad..a93f33eb32c2ce68982200d299208698402a3b40 100644
--- a/tools/telemetry/telemetry/page/page_set_archive_info.py
+++ b/tools/telemetry/telemetry/page/page_set_archive_info.py
@@ -8,6 +8,7 @@ import os
 import re
 import shutil
 
+from telemetry.core.backends.chrome import cros_interface
 from telemetry.page import cloud_storage
 
 
@@ -22,16 +23,28 @@ class PageSetArchiveInfo(object):
 
     # Download all .wpr files.
     if not ignore_archive:
+      # TODO(tbarzic): Remove this once http://crbug.com/351143 is diagnosed.
+      log_cloud_storage_exception = cros_interface.IsRunningOnCrosDevice()
       for archive_path in data['archives']:
         archive_path = self._WprFileNameToPath(archive_path)
         try:
           cloud_storage.GetIfChanged(archive_path)
-        except (cloud_storage.CredentialsError, cloud_storage.PermissionError):
+        except (cloud_storage.CredentialsError,
+                cloud_storage.PermissionError) as e:
           if os.path.exists(archive_path):
             # If the archive exists, assume the user recorded their own and
             # simply warn.
             logging.warning('Need credentials to update WPR archive: %s',
                             archive_path)
+          elif log_cloud_storage_exception:
+            # Log access errors only once, as they should stay the same in other
+            # iterations.
+            log_cloud_storage_exception = False
+            logging.warning('Error getting WPR archive %s: %s ' %
+                                (archive_path, str(e)))
+            logging.info(
+                'HOME: "%s"; USER: "%s"' %
+                (os.environ.get('HOME', ''), os.environ.get('USER', '')))
 
     # Map from the relative path (as it appears in the metadata file) of the
     # .wpr file to a list of page names it supports.
@@ -53,6 +66,9 @@ class PageSetArchiveInfo(object):
       with open(file_path, 'r') as f:
         data = json.load(f)
         return cls(file_path, data, ignore_archive=ignore_archive)
+    # TODO(tbarzic): Remove this once http://crbug.com/351143 is diagnosed.
+    if cros_interface.IsRunningOnCrosDevice():
+      logging.warning('Page set archives not found: %s' % file_path)
     return cls(file_path, {'archives': {}}, ignore_archive=ignore_archive)
 
   def WprFilePathForPage(self, page):