[Findit] Process analysis requests of Waterfall failures concurrently.

appengine/findit/waterfall/build_failure_analysis_pipelines.py

Index: appengine/findit/waterfall/build_failure_analysis_pipelines.py
diff --git a/appengine/findit/waterfall/build_failure_analysis_pipelines.py b/appengine/findit/waterfall/build_failure_analysis_pipelines.py
index 72e5801801f0b03b0c0d0d028aca2993fec91d12..291a4b4eae34d1c3a2e2c8e9abc9c8d1cf43e8f3 100644
--- a/appengine/findit/waterfall/build_failure_analysis_pipelines.py
+++ b/appengine/findit/waterfall/build_failure_analysis_pipelines.py
@@ -42,6 +42,7 @@ def NeedANewAnalysis(
     if not analysis.completed:
       # TODO: start a new analysis if the last one has started running but it
       # has no update for a considerable amount of time, eg. 10 minutes.
+      logging.info('Existing analysis is not completed yet. No new analysis.')
       return False
 
     analysis.Reset()
@@ -69,6 +70,7 @@ def NeedANewAnalysis(
   # TODO: support following cases
   # * Automatically retry if last analysis failed with errors.
   # * Analysis is not complete and no update in the last 5 minutes.
+  logging.info('Not match any cases. No new analysis.')
   return False
 
 
@@ -118,5 +120,8 @@ def ScheduleAnalysisIfNeeded(master_name, builder_name, build_number,
     logging.info('An analysis was scheduled for build %s, %s, %s: %s',
                  master_name, builder_name, build_number,
                  pipeline_job.pipeline_status_path())
+  else:
+    logging.info('An analysis is not needed for build %s, %s, %s',
+                 master_name, builder_name, build_number)
 
   return WfAnalysis.Get(master_name, builder_name, build_number)