[Findit] Add iterator and crash_iterator for delta test

appengine/findit/util_scripts/crash_queries/crash_printer/print_crash.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.
+
+import argparse
+from datetime import date
+from datetime import timedelta
+
+from crash_queries.crash_printer import crash_printer
+
+_TODAY = date.today().strftime('%Y-%m-%d')
+_A_YEAR_AGO = (date.today() - timedelta(days=365)).strftime('%Y-%m-%d')
+
+
+if __name__ == '__main__':
+  argparser = argparse.ArgumentParser(
+      description='Print crashes.')
+
+  argparser.add_argument(
+      '--date',
+      '-d',
+      default='%s..%s' % (_A_YEAR_AGO, _TODAY),
+      help=('Should be in start_date..end_date format.'
+            'If it\' 2016-08-01.., default end_date to today, if it\'s '

[wrengr, 2016/10/05 18:41:59]

-> "If the end date is missing, then it defaults to today. If the start date is
missing, then it defaults to a year before the end date."

[Sharu Jiang, 2016/10/06 18:16:56]

Done.

+            '..2016-08-16, default start_date to a year ago.'
+            'Start date and end date to query data in [start_date, end_date)'))
+
+  argparser.add_argument(
+      '--client',
+      '-c',
+      default='fracas',
+      help=('Should be one in fracas/cracas/clusterfuzz. Right now, only '

[wrengr, 2016/10/05 18:41:58]

-> "Possible values are: fracas, cracas, clusterfuzz."

[Sharu Jiang, 2016/10/06 18:16:56]

Done.

+            'fracas is supported.'))
+
+  args = argparser.parse_args()
+
+  start_date, end_date = args.date.split('..')
+  if not start_date:

[wrengr, 2016/10/05 18:41:58]

Is this not redundant?

[Sharu Jiang, 2016/10/06 18:16:56]

Oops, should be _A_YEAR_AGO

+    start_date = None
+  if not end_date:
+    end_date = None
+
+  crash_printer.CrashPrinter(args.client,
+                             start_date=start_date, end_date=end_date)