Change models.py to use typed class members instead of a list of strings.

verification/tree_status.py

 # coding=utf8
 # Copyright (c) 2012 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.
 """Postpone commits until the tree is open."""
 
 import calendar
 import json
 import logging
 import time
 import urllib2
 
 from verification import base
 
 
 class TreeStatus(base.IVerifierStatus):
-  persistent = base.IVerifierStatus.persistent + [
-      'tree_status_url',
-  ]
-
-  def __init__(self, tree_status_url):
-    super(TreeStatus, self).__init__()
-    self.tree_status_url = tree_status_url
+  tree_status_url = str

[csharp, 2012/11/23 18:31:58]

Is it ok for this class to now get constructed without tree_status_url getting
explicitly set? It's ok to get set to just a default str?

This same question applies to a few of the other removed __init__ functions

[M-A Ruel, 2012/11/23 18:44:06]

First, some background: it's a design issue that this instance doesn't know
about its parent, TreeStatusVerifier, which does know about the tree status url.
Since it doesn't know about the parent, it can't fetch the value. That's why I
copy it here too. It's not optimal from a design standpoint but it gets the job
done.

You are right that it must be non-empty to be of any use but I did not want to
add features like required=True in models.py. I left it out since I want to keep
the code in models.py as simple as possible. Adding member attributes likes
required=True would require usage of an object to represent the member type,
like how it's done in django[1] and AppEngine[2]. The goal here is to be
lighter-weight than that but a bit more structured than it was before.

[1]
https://docs.djangoproject.com/en/dev/howto/custom-model-fields/#django.db.mo...
[2]
https://developers.google.com/appengine/docs/python/datastore/typesandpropert...

 
   def get_state(self):
     return base.SUCCEEDED
 
   def postpone(self):
     try:
       logging.debug('Fetching tree status for %s' % self.tree_status_url)
       now = time.time()
       cutoff = now - 5 * 60
       url = self.tree_status_url + '/allstatus?format=json&endTime=%d' % cutoff
@@ skipping 24 matching lines @@
   def __init__(self, tree_status_url):
     super(TreeStatusVerifier, self).__init__()
     self.tree_status_url = tree_status_url
 
   def verify(self, pending):
     pending.verifications[self.name] = TreeStatus(
         tree_status_url=self.tree_status_url)
 
   def update_status(self, queue):
     pass