WIP to improve Telemetry logging

telemetry/telemetry/internal/story_runner.py

Index: telemetry/telemetry/internal/story_runner.py
diff --git a/telemetry/telemetry/internal/story_runner.py b/telemetry/telemetry/internal/story_runner.py
index 8928068ab3bdf89aaefb16edf51c7007a27ed7ea..073e4bcd22dbee92f4a97580ddbded197a409636 100644
--- a/telemetry/telemetry/internal/story_runner.py
+++ b/telemetry/telemetry/internal/story_runner.py
@@ -17,6 +17,7 @@ from telemetry.internal.actions import page_action
 from telemetry.internal.browser import browser_finder
 from telemetry.internal.results import results_options
 from telemetry.internal.util import exception_formatter
+from telemetry.internal.util import log_stream
 from telemetry import page
 from telemetry.page import legacy_page_test
 from telemetry import story as story_module
@@ -88,6 +89,9 @@ def _GenerateTagMapFromStorySet(stories):
 
 def _RunStoryAndProcessErrorIfNeeded(story, results, state, test):
   def ProcessError(description=None):
+    # Flush all the existing log upon failure.
+    log_stream.FlushLogStream(sys.stdout)
+
     state.DumpStateUponFailure(story, results)
     # Note: adding the FailureValue to the results object also normally
     # cause the progress_reporter to log it in the output.
@@ -179,6 +183,7 @@ def Run(test, story_set, finder_options, results, max_failures=None,
   try:
     for storyset_repeat_counter in xrange(finder_options.pageset_repeat):
       for story in stories:
+        log_stream.TruncateLogStream()
         if not state:
           # Construct shared state by using a copy of finder_options. Shared
           # state may update the finder_options. If we tear down the shared