Merge lp:~stub/launchpad/cache-bugcomments into lp:launchpad

[Stuart Bishop]

Cache bug comments much more aggressively.

Cache bug comments much more aggressively.

[Stuart Bishop (stub)]

Full test suite has not yet been run so there may be fallout. Sending to ec2.

[Graham Binns (gmb)]

review: Approve (code)

=== modified file 'lib/lp/bugs/browser/bugcomment.py'
--- lib/lp/bugs/browser/bugcomment.py	2010-03-22 16:49:55 +0000
+++ lib/lp/bugs/browser/bugcomment.py	2010-06-23 03:29:30 +0000
@@ -10,11 +10,14 @@
     'BugCommentBoxView',
     'BugCommentBoxExpandedReplyView',
     'BugCommentXHTMLRepresentation',
-    'BugMessageBreadcrumb',
+    'BugCommentBreadcrumb',
     'build_comments_from_chunks',
     'should_display_remote_comments',
     ]
 
+from datetime import datetime, timedelta
+from pytz import utc
+
 from zope.component import adapts, getMultiAdapter, getUtility
 from zope.interface import implements, Interface
 
@@ -213,6 +216,39 @@
         else:
             return False
 
+    @property
+    def rendered_cache_time(self):
+        """The number of seconds we can cache the rendered comment for.
+
+        Bug comments are cached with 'authenticated' visibility, so
+        should contain no information hidden from some users. We use
+        'authenticated' rather than 'public' as email addresses are
+        obfuscated for unauthenticated users.
+        """
+        now = datetime.now(tz=utc)
+        # The major factor in how long we can cache a bug comment is
+        # the timestamp. The rendering of the timestamp changes every
+        # minute for the first hour because we say '7 minutes ago'.
+        if self.datecreated > now - timedelta(hours=1):
+            return 60
+
+        # Don't cache for long if we are waiting for synchronization.
+        elif self.bugwatch and not self.synchronized:
+            return 5*60
+
+        # For the rest of the first day, the rendering changes every
+        # hour. '4 hours ago'. Expire in 15 minutes so the timestamp
+        # is at most 15 minutes out of date.
+        elif self.datecreated > now - timedelta(days=1):
+            return 15*60
+
+        # Otherwise, cache away. Lets cache for 6 hours. We don't want
+        # to cache for too long as there are still things that can
+        # become stale - eg. if a bug attachment has been deleted we
+        # should stop rendering the link.
+        else:
+            return 6*60*60
+
 
 class BugCommentView(LaunchpadView):
     """View for a single bug comment."""

=== modified file 'lib/lp/bugs/interfaces/bugmessage.py'
--- lib/lp/bugs/interfaces/bugmessage.py	2010-01-12 09:38:00 +0000
+++ lib/lp/bugs/interfaces/bugmessage.py	2010-06-23 03:29:30 +0000
@@ -127,3 +127,5 @@
         "Whether or not to show a footer for the comment.")
     patches = Attribute(
         "Patches attched to this comment.")
+    rendered_cache_time = Attribute(
+        "How long we can cache the rendered comment for.")

=== modified file 'lib/lp/bugs/templates/bugcomment-box.pt'
--- lib/lp/bugs/templates/bugcomment-box.pt	2010-04-06 07:27:01 +0000
+++ lib/lp/bugs/templates/bugcomment-box.pt	2010-06-23 03:29:30 +0000
@@ -8,7 +8,8 @@
               admin_comment_hidden_class
               python: comment.show_for_admin and 'adminHiddenComment' or ''"
   tal:attributes="class string:boardComment ${remote_bug_comment_class}
-                 ${admin_comment_hidden_class}">
+                 ${admin_comment_hidden_class}"
+  tal:content="cache:authenticated,comment/rendered_cache_time,comment/index">
 
   <div class="boardCommentDetails">
     <table>
@@ -55,9 +56,11 @@
 
   <div class="boardCommentBody">
     <ul tal:condition="comment/bugattachments" style="margin-bottom: 1em">
-      <li tal:repeat="attachment comment/bugattachments" class="download-attachment">
+      <li tal:repeat="attachment comment/bugattachments"
+            class="download-attachment">
         <a tal:attributes="href attachment/libraryfile/http_url"
-           tal:content="attachment/title" class="sprite download-icon">foo.txt</a>
+            tal:content="attachment/title"
+            class="sprite download-icon">foo.txt</a>
         (<span
            tal:replace="attachment/libraryfile/content/filesize/fmt:bytes" />,
         <span tal:replace="attachment/libraryfile/mimetype" />)
@@ -83,8 +86,7 @@
       <a tal:attributes="href comment/fmt:url">Read more...</a>
     </p>
   </div>
-  <div class="boardCommentFooter" tal:condition="comment/show_footer"
-    tal:content="cache:authenticated,30 minutes,comment/index">
+  <div class="boardCommentFooter" tal:condition="comment/show_footer">
     <tal:activity
         define="activity_list comment/activity"
         condition="comment/activity">