[Findit] Query master flake analyses 100 at a time and add previous/next buttons to check flake dash

appengine/findit/handlers/flake/list_flakes.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from datetime import datetime
 from datetime import time
 from datetime import timedelta
 
 from common.base_handler import BaseHandler
 from common.base_handler import Permission
 
 from lib import time_util
 from model import result_status
 from model.flake.master_flake_analysis import MasterFlakeAnalysis
 
 
+PAGE_SIZE = 100
+
+
 def FilterMasterFlakeAnalysis(
     master_flake_analysis_query, master_name=None, builder_name=None,
     build_number=None, step_name=None, test_name=None, start_date=None,
-    end_date=None, status_code=result_status.UNSPECIFIED):
+    end_date=None, status_code=result_status.UNSPECIFIED, offset=0):

[stgao, 2016/12/01 18:26:06]

We'd better use cursor instead of offset for performance, IIRC.

   if master_name:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.master_name == master_name)
   if builder_name:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.builder_name == builder_name)
   if build_number:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.build_number == build_number)
   if step_name:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.step_name == step_name)
   if test_name:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.test_name == test_name)
   if start_date:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.request_time >= start_date)
   if end_date:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.request_time < end_date)
   if status_code != result_status.UNSPECIFIED:
     master_flake_analysis_query = master_flake_analysis_query.filter(
         MasterFlakeAnalysis.result_status == status_code)
 
   master_flake_analysis_query.order(-MasterFlakeAnalysis.request_time)
-  return master_flake_analysis_query.fetch()
+
+  # TODO(lijeffrey): use cursor instead of offset.
+  analyses, _, more = master_flake_analysis_query.fetch_page(
+      PAGE_SIZE, offset=offset)
+
+  return analyses, more
 
 
 class ListFlakes(BaseHandler):
   PERMISSION_LEVEL = Permission.ANYONE
 
   def _GetStartAndEndDates(self, triage):
     start_date = None
     end_date = None
 
     if triage:
@@ skipping 14 matching lines @@
     status_code = int(
         self.request.get('result_status', result_status.UNSPECIFIED))
     master_name = self.request.get('master_name').strip()
     builder_name = self.request.get('builder_name').strip()
     build_number = self.request.get('build_number').strip()
     if build_number:
       build_number = int(build_number)
     step_name = self.request.get('step_name').strip()
     test_name = self.request.get('test_name').strip()
     triage = self.request.get('triage') == '1'
+    offset = int(self.request.get('offset', '0').strip())
 
     # Only allow querying by start/end dates for admins during triage to avoid
     # overcomplicating the UI for other users.
     start_date, end_date = self._GetStartAndEndDates(triage)
 
-    master_flake_analyses = FilterMasterFlakeAnalysis(
+    master_flake_analyses, more = FilterMasterFlakeAnalysis(
         MasterFlakeAnalysis.query(), master_name, builder_name, build_number,
-        step_name, test_name, start_date, end_date, status_code)
+        step_name, test_name, start_date, end_date, status_code, offset)
 
     data = {
         'master_flake_analyses': [],
         'result_status_filter': status_code,
         'master_name_filter': master_name,
         'builder_name_filter': builder_name,
         'build_number_filter': build_number,
         'step_name_filter': step_name,
-        'test_name_filter': test_name
+        'test_name_filter': test_name,
+        'page_size': PAGE_SIZE,
+        'offset': offset,
+        'more': more,
     }
 
     if triage:  # pragma: no cover
       data['triage'] = triage
       data['start_date'] = start_date
       data['end_date'] = end_date
 
     for master_flake_analysis in master_flake_analyses:
       data['master_flake_analyses'].append({
           'master_name': master_flake_analysis.master_name,
@@ skipping 11 matching lines @@
 
     # TODO (stgao): use index instead of in-memory sort.
     # Index doesn't work for now, possibly due to legacy data.
     data['master_flake_analyses'].sort(
         key=lambda e: e['request_time'], reverse=True)
 
     return {
         'template': 'flake/dashboard.html',
         'data': data
     }