Merge lp:~gmb/launchpad/bugzilla-3.4-init-db-bug-416514 into lp:launchpad

[Graham Binns]

[Graham Binns (gmb)]

This branch adds an initializeRemoteBugDB() method to the BugzillaAPI
ExternalBugTracker, in accordance with IExternalBugTracker. I've
refactored a couple of methods out of BugzillaLPPlugin, which descends
from BugzillaAPI, and into the BugzillaAPI class because they are useful
utilities.

I've also refactored the associated tests into the bugzilla-api doctest.

Note that this branch is based on a branch that hasn't yet landed (but
which is r=cprov). Please use the diff below rather than the one
generated by the merge proposal.

Launchpad lint
--------------

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt
  lib/lp/bugs/doc/externalbugtracker-bugzilla-lp-plugin.txt
  lib/lp/bugs/externalbugtracker/bugzilla.py
  lib/lp/bugs/tests/bugzilla-xmlrpc-transport.txt
  lib/lp/bugs/tests/externalbugtracker.py

Diff of changes
---------------

=== modified file 'lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt'
--- lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt 2009-08-20 15:43:37 +0000
+++ lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt 2009-08-21 09:51:57 +0000
@@ -111,3 +111,111 @@
     >>> bugzilla.getCurrentDBTime()
     CALLED Bugzilla.time()
     datetime.datetime(2009, 8, 19, 22, 2, 2, tzinfo=<UTC>)
+
+
+Initializing the bug database
+-----------------------------
+
+BugzillaAPI implements IExternalBugTracker.initializeRemoteBugDB(),
+which takes a list of bug IDs to fetch from the remote server and stores
+those bugs locally for future use.
+
+ >>> bugzilla.initializeRemoteBugDB([1, 2])
+ CALLED Bug.get({'ids': [1, 2], 'permissive': True})
+
+The bug data is stored as a list of dicts:
+
+ >>> def print_bugs(bugs):
+ ... for bug in sorted(bugs):
+ ... print "Bug %s:" % bug
+ ... for key in sorted(bugzilla._bugs[bug]):
+ ... print " %s: %s" % (key, bugzilla._bugs[bug][key])
+ ... print "\n"
+
+ >>> print_bugs(bugzilla._bugs)
+ Bug 1:
+ alias:
+ assigned_to: <email address hidden>
+ component: GPPSystems
+ creation_time: 20080610T16:19:53
+ id: 1
+ internals:...
+ is_open: True
+ last_change_time: 20080610T16:19:53
+ priority: P1
+ product: Marvin
+ resolution: FIXED
+ severity: normal
+ status: RESOLVED
+ summary: That bloody robot still exists.
+ <BLANKLINE>
+ Bug 2:
+ alias: bug-two
+ assigned_to: <email address hidden>
+ component: Crew
+ creation_time: 20080611T09:23:12
+ id: 2
+ internals:...
+ is_open: True
+ last_change_time: 20080611T09:24:29
+ priority: P1
+ product: HeartOfGold
+ resolution:
+ severity: high
+ status: NEW
+ summary: Collect unknown persons in docking bay 2.
+ <BLANKLINE>
+ <BLANKLINE>
+
+
+Storing bugs
+------------
+
+initializeRemoteBugDB() uses the _storeBugs() method to store bug data.
+_storeBugs() will only store a bug once, even if it is requested both by
+alias and ID...

[Abel Deuring (adeuring)]

Hi Graham,

nice branch. No complaints, but I found a few lines with trailing spaces.
Could you remove them?

r=me

Abel

> === modified file 'lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt'
> --- lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt 2009-08-20 15:43:37 +0000
> +++ lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt 2009-08-21 09:51:57 +0000
> @@ -111,3 +111,111 @@
> >>> bugzilla.getCurrentDBTime()
> CALLED Bugzilla.time()
> datetime.datetime(2009, 8, 19, 22, 2, 2, tzinfo=<UTC>)
> +
> +
> +Initializing the bug database
> +-----------------------------
> +
> +BugzillaAPI implements IExternalBugTracker.initializeRemoteBugDB(),
> +which takes a list of bug IDs to fetch from the remote server and stores
> +those bugs locally for future use.
> +
> + >>> bugzilla.initializeRemoteBugDB([1, 2])
> + CALLED Bug.get({'ids': [1, 2], 'permissive': True})
> +
> +The bug data is stored as a list of dicts:
> +
> + >>> def print_bugs(bugs):
> + ... for bug in sorted(bugs):
> + ... print "Bug %s:" % bug
> + ... for key in sorted(bugzilla._bugs[bug]):
> + ... print " %s: %s" % (key, bugzilla._bugs[bug][key])
> + ... print "\n"
> +
> + >>> print_bugs(bugzilla._bugs)
> + Bug 1:
> + alias:

trailing space.

> + assigned_to: <email address hidden>
> + component: GPPSystems
> + creation_time: 20080610T16:19:53
> + id: 1
> + internals:...
> + is_open: True
> + last_change_time: 20080610T16:19:53
> + priority: P1
> + product: Marvin
> + resolution: FIXED
> + severity: normal
> + status: RESOLVED
> + summary: That bloody robot still exists.
> + <BLANKLINE>
> + Bug 2:
> + alias: bug-two
> + assigned_to: <email address hidden>
> + component: Crew
> + creation_time: 20080611T09:23:12
> + id: 2
> + internals:...
> + is_open: True
> + last_change_time: 20080611T09:24:29
> + priority: P1
> + product: HeartOfGold
> + resolution:

trailing space.

> + severity: high
> + status: NEW
> + summary: Collect unknown persons in docking bay 2.
> + <BLANKLINE>
> + <BLANKLINE>
> +
> +
> +Storing bugs
> +------------
> +
> +initializeRemoteBugDB() uses the _storeBugs() method to store bug data.
> +_storeBugs() will only store a bug once, even if it is requested both by
> +alias and ID. We'll reset the test BugzillaAPI's _bugs and _bug_aliases
> +dicts to demonstrate this.
> +
> + >>> bugzilla._bugs = {}
> + >>> bugzilla._bug_aliases = {}
> + >>> bugzilla.initializeRemoteBugDB([2, 'bug-two'])
> + CALLED Bug.get({'ids': [2, 'bug-two'], 'permissive': True})
> +
> + >>> for bug in sorted(bugzilla._bugs):
> + ... print "Bug %r:" % bug
> + ... for key in sorted(bugzilla._bugs[bug]):
> + ... print " %s: %s" % (key, bugzilla._bugs[bug][key])
> + ... print "\n"
> + Bug 2:
> + alias: bug-two
> + assigned_to: <email address hidden>
> + component: Crew
> + creation_time: 20080611T09:23:12
> + id: 2
> +...

review: Approve (code)

=== modified file 'lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt'
--- lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt	2009-08-19 13:12:30 +0000
+++ lib/lp/bugs/doc/externalbugtracker-bugzilla-api.txt	2009-08-21 09:32:57 +0000
@@ -75,3 +75,147 @@
         ...
     BugTrackerAuthenticationError: http://thiswillfail.example.com:
     Fault 300: The username or password you entered is not valid.
+
+
+Getting the server time
+-----------------------
+
+To be able to accurately sync with a bug tracker, we need to be able to
+check the time on the remote server. We use BugzillaAPI.getCurrentDBTime()
+to get the current time on the remote server.
+
+    # There's no way to create a UTC timestamp without monkey-patching
+    # the TZ environment variable. Rather than do that, we create our
+    # own datetime and work with that.
+    >>> from datetime import datetime
+    >>> remote_time = datetime(2009, 8, 19, 17, 2, 2)
+
+    >>> test_transport.local_datetime = remote_time
+    >>> bugzilla.getCurrentDBTime()
+    CALLED Bugzilla.time()
+    datetime.datetime(2009, 8, 19, 17, 2, 2, tzinfo=<UTC>)
+
+If the remote system is in a different timezone, getCurrentDBTime() will
+convert its time to UTC before returning it.
+
+    >>> test_transport.utc_offset = 60**2
+    >>> test_transport.timezone = 'CET'
+    >>> bugzilla.getCurrentDBTime()
+    CALLED Bugzilla.time()
+    datetime.datetime(2009, 8, 19, 16, 2, 2, tzinfo=<UTC>)
+
+This works whether the UTC offset is positive or negative.
+
+    >>> test_transport.utc_offset = -5 * 60**2
+    >>> test_transport.timezone = 'US/Eastern'
+    >>> bugzilla.getCurrentDBTime()
+    CALLED Bugzilla.time()
+    datetime.datetime(2009, 8, 19, 22, 2, 2, tzinfo=<UTC>)
+
+
+Initializing the bug database
+-----------------------------
+
+BugzillaAPI implements IExternalBugTracker.initializeRemoteBugDB(),
+which takes a list of bug IDs to fetch from the remote server and stores
+those bugs locally for future use.
+
+    >>> bugzilla.initializeRemoteBugDB([1, 2])
+    CALLED Bug.get({'ids': [1, 2], 'permissive': True})
+
+The bug data is stored as a list of dicts:
+
+    >>> def print_bugs(bugs):
+    ...     for bug in sorted(bugs):
+    ...         print "Bug %s:" % bug
+    ...         for key in sorted(bugzilla._bugs[bug]):
+    ...             print "    %s: %s" % (key, bugzilla._bugs[bug][key])
+    ...         print "\n"
+
+    >>> print_bugs(bugzilla._bugs)
+    Bug 1:
+        alias: 
+        assigned_to: [e-mail]
+        component: GPPSystems
+        creation_time: 20080610T16:19:53
+        id: 1
+        internals:...
+        is_open: True
+        last_change_time: 20080610T16:19:53
+        priority: P1
+        product: Marvin
+        resolution: FIXED
+        severity: normal
+        status: RESOLVED
+        summary: That bloody robot still exists.
+    <BLANKLINE>
+    Bug 2:
+        alias: bug-two
+        assigned_to: [e-mail]
+        component: Crew
+        creation_time: 20080611T09:23:12
+        id: 2
+        internals:...
+        is_open: True
+        last_change_time: 20080611T09:24:29
+        priority: P1
+        product: HeartOfGold
+        resolution: 
+        severity: high
+        status: NEW
+        summary: Collect unknown persons in docking bay 2.
+    <BLANKLINE>
+    <BLANKLINE>
+
+
+Storing bugs
+------------
+
+initializeRemoteBugDB() uses the _storeBugs() method to store bug data.
+_storeBugs() will only store a bug once, even if it is requested both by
+alias and ID. We'll reset the test BugzillaAPI's _bugs and _bug_aliases
+dicts to demonstrate this.
+
+    >>> bugzilla._bugs = {}
+    >>> bugzilla._bug_aliases = {}
+    >>> bugzilla.initializeRemoteBugDB([2, 'bug-two'])
+    CALLED Bug.get({'ids': [2, 'bug-two'], 'permissive': True})
+
+    >>> for bug in sorted(bugzilla._bugs):
+    ...     print "Bug %r:" % bug
+    ...     for key in sorted(bugzilla._bugs[bug]):
+    ...         print "    %s: %s" % (key, bugzilla._bugs[bug][key])
+    ...     print "\n"
+    Bug 2:
+        alias: bug-two
+        assigned_to: [e-mail]
+        component: Crew
+        creation_time: 20080611T09:23:12
+        id: 2
+        internals:...
+        is_open: True
+        last_change_time: 20080611T09:24:29
+        priority: P1
+        product: HeartOfGold
+        resolution: 
+        severity: high
+        status: NEW
+        summary: Collect unknown persons in docking bay 2.
+    <BLANKLINE>
+    <BLANKLINE>
+
+Aliases are stored in a separate dict, which contains a mapping between
+the alias and the bug's actual ID.
+
+    >>> for alias, bug_id in bugzilla._bug_aliases.items():
+    ...     print "%s: %s" % (alias, bug_id)
+    bug-two: 2
+
+The method _getActualBugId() returns the correct bug ID for a passed bug
+ID or alias.
+
+    >>> bugzilla._getActualBugId('bug-two')
+    2
+
+    >>> bugzilla._getActualBugId(2)
+    2
 
=== modified file 'lib/lp/bugs/doc/externalbugtracker-bugzilla-lp-plugin.txt'
--- lib/lp/bugs/doc/externalbugtracker-bugzilla-lp-plugin.txt	2009-08-19 09:22:08 +0000
+++ lib/lp/bugs/doc/externalbugtracker-bugzilla-lp-plugin.txt	2009-08-21 09:32:57 +0000
@@ -1,4 +1,5 @@
-= Bugzilla bugtrackers with the Launchpad plugin =
+Bugzilla bugtrackers with the Launchpad plugin
+==============================================
 
 These tests cover the BugzillaLPPlugin ExternalBugTracker, which handles
 Bugzilla instances that have the Launchpad plugin installed.
@@ -25,7 +26,8 @@
     True
 
 
-== Authentication ==
+Authentication
+--------------
 
 XML-RPC methods that modify data on the remote server require
 authentication. To authenticate, we create a LoginToken of type
@@ -154,7 +156,8 @@
     Protocol error: 500 "Internal server error"
 
 
-== Getting the current time ==
+Getting the current time
+------------------------
 
 The BugzillaLPPlugin ExternalBugTracker, like all other
 ExternalBugTrackers, has a getCurrentDBTime() method, which returns the
@@ -173,7 +176,8 @@
     datetime.datetime(2008, 5, 16, 15, 53, 20, tzinfo=<UTC>)
 
 
-== Initializing the remote bug database ==
+Initializing the remote bug database
+------------------------------------
 
 The BugzillaLPPlugin implements the standard initializeRemoteBugDB()
 method, taking a list of the bug ids that need to be updated. It uses
@@ -228,56 +232,13 @@
     <BLANKLINE>
     <BLANKLINE>
 
-initializeRemoteBugDB() will only store a bug once, even if it is
-requested both by alias and ID. We'll reset the test BugzillaLPPlugin's
-_bugs and _bug_aliases dicts to demonstrate this.
-
-    >>> bugzilla._bugs = {}
-    >>> bugzilla._bug_aliases = {}
-    >>> bugzilla.initializeRemoteBugDB([2, 'bug-two'])
-    CALLED Launchpad.get_bugs({'ids': [2, 'bug-two'], 'permissive': True})
-
-    >>> for bug in sorted(bugzilla._bugs):
-    ...     print "Bug %r:" % bug
-    ...     for key in sorted(bugzilla._bugs[bug]):
-    ...         print "    %s: %s" % (key, bugzilla._bugs[bug][key])
-    ...     print "\n"
-    Bug 2:
-        alias: bug-two
-        assigned_to: [e-mail]
-        component: Crew
-        creation_time: 20080611T09:23:12
-        id: 2
-        internals:...
-        is_open: True
-        last_change_time: 20080611T09:24:29
-        priority: P1
-        product: HeartOfGold
-        resolution: 
-        severity: high
-        status: NEW
-        summary: Collect unknown persons in docking bay 2.
-    <BLANKLINE>
-    <BLANKLINE>
-
-Aliases are stored in a separate dict, which contains a mapping between
-the alias and the bug's actual ID.
-
-    >>> for alias, bug_id in bugzilla._bug_aliases.items():
-    ...     print "%s: %s" % (alias, bug_id)
-    bug-two: 2
-
-The method _getActualBugId() returns the correct bug ID for a passed bug
-ID or alias.
-
-    >>> bugzilla._getActualBugId('bug-two')
-    2
-
-    >>> bugzilla._getActualBugId(2)
-    2
-
-
-== Getting a list of changed bugs ==
+BugzillaLPPlugin.initializeRemoteBugDB() uses its _storeBugs() method to
+store bugs. See externalbugtracker-bugzilla-api.txt for details of
+_storeBugs().
+
+
+Getting a list of changed bugs
+------------------------------
 
 IExternalBugTracker defines a method, getModifiedRemoteBugs(), which
 accepts a list of bug IDs and a datetime as a parameter and returns the
@@ -337,7 +298,8 @@
     CALLED Launchpad.get_bugs({'ids': [3], 'permissive': True})
 
 
-== Getting remote statuses ==
+Getting remote statuses
+-----------------------
 
 BugzillaLPPlugin.getRemoteStatus() will return the remote status of a
 given bug as a string. If the bug has a resolution, that will be
@@ -369,7 +331,8 @@
     >>> del bugzilla._bugs[999]
 
 
-== Getting the remote product ==
+Getting the remote product
+--------------------------
 
 getRemoteProduct() returns the product a remote bug is associated with
 in Bugzilla. 
@@ -393,7 +356,8 @@
     BugNotFound: 12345
 
 
-== Retrieving remote comments ==
+Retrieving remote comments
+--------------------------
 
 BugzillaLPPlugin implments the ISupportsCommentImport interface, which
 means that we can use it to import comments from the remote Bugzilla
@@ -435,7 +399,8 @@
     >>> LaunchpadZopelessLayer.switchDbUser(config.checkwatches.dbuser)
 
 
-=== getCommentIds() ===
+getCommentIds()
+---------------
 
 ISupportsCommentImport.getCommentIds() is the method used to get all the
 comment IDs for a given bug on a remote bugtracker.
@@ -456,7 +421,8 @@
     BugNotFound: 42
 
 
-=== fetchComments() ===
+fetchComments()
+---------------
 
 ISupportsCommentImport.fetchComments() is the method used to fetch a
 given set of comments from the remote bugtracker. It takes a bug watch
@@ -488,7 +454,8 @@
         time: 20080616T13:22:29
 
 
-=== getPosterForComment() ===
+getPosterForComment()
+---------------------
 
 ISupportsCommentImport.getPosterForComment() returns a tuple of
 (displayname, email) for the author of a remote comment.
@@ -507,7 +474,8 @@
     None trillian
 
 
-=== getMessageForComment() ===
+getMessageForComment()
+----------------------
 
 ISupportsCommentImport.getMessageForComment() returns a Launchpad
 IMessage instance for a given comment. It takes a bug watch, a comment
@@ -533,7 +501,8 @@
     2008-06-16 13:08:08+00:00
 
 
-== Pushing comments to remote systems ==
+Pushing comments to remote systems
+----------------------------------
 
 BugzillaLPPlugin implements the ISupportsCommentPushing interface, which
 defines the necessary methods for pushing comments to remote servers.
@@ -583,7 +552,8 @@
     <BLANKLINE>
 
 
-== Linking remote bugs to Launchpad bugs ==
+Linking remote bugs to Launchpad bugs
+-------------------------------------
 
 BugzillaLPPlugin implements the ISupportsBackLinking interface, which
 provides methods to set and retrieve the Launchpad bug that links to a
@@ -644,7 +614,8 @@
     10
 
 
-== Working with a specified set of Bugzilla products ==
+Working with a specified set of Bugzilla products
+-------------------------------------------------
 
 BugzillaLPPlugin can be instructed to only get the data for a set of
 bug IDs if those bugs belong to one of a given set of products.
@@ -691,7 +662,8 @@
     0
 
 
-== Getting the products for a set of remote bugs ==
+Getting the products for a set of remote bugs
+---------------------------------------------
 
 BugzillaLPPlugin provides a helper method, getProductsForRemoteBugs(),
 which takes a list of bug IDs or aliases and returns the products to
 
=== modified file 'lib/lp/bugs/externalbugtracker/bugzilla.py'
--- lib/lp/bugs/externalbugtracker/bugzilla.py	2009-08-19 13:19:22 +0000
+++ lib/lp/bugs/externalbugtracker/bugzilla.py	2009-08-21 09:32:57 +0000
@@ -430,6 +430,98 @@
                 self.baseurl,
                 "Fault %s: %s" % (fault.faultCode, fault.faultString))
 
+    def _storeBugs(self, remote_bugs):
+        """Store remote bugs in the local `bugs` dict."""
+        for remote_bug in remote_bugs:
+            self._bugs[remote_bug['id']] = remote_bug
+
+            # The bug_aliases dict is a mapping between aliases and bug
+            # IDs. We use the aliases dict to look up the correct ID for
+            # a bug. This allows us to reference a bug by either ID or
+            # alias.
+            if remote_bug['alias'] != '':
+                self._bug_aliases[remote_bug['alias']] = remote_bug['id']
+
+    def getCurrentDBTime(self):
+        """See `IExternalBugTracker`."""
+        time_dict = self.xmlrpc_proxy.Bugzilla.time()
+
+        # Convert the XML-RPC DateTime we get back into a regular Python
+        # datetime.
+        server_db_timetuple = time.strptime(
+            str(time_dict['db_time']), '%Y%m%dT%H:%M:%S')
+        server_db_datetime = datetime(*server_db_timetuple[:6])
+
+        # The server's DB time is the one that we want to use. However,
+        # this may not be in UTC, so we need to convert it. Since we
+        # can't guarantee that the timezone data returned by the server
+        # is sane, we work out the server's offset from UTC by looking
+        # at the difference between the web_time and the web_time_utc
+        # values.
+        server_web_time = time.strptime(
+            str(time_dict['web_time']), '%Y%m%dT%H:%M:%S')
+        server_web_datetime = datetime(*server_web_time[:6])
+        server_web_time_utc = time.strptime(
+            str(time_dict['web_time_utc']), '%Y%m%dT%H:%M:%S')
+        server_web_datetime_utc = datetime(*server_web_time_utc[:6])
+
+        server_utc_offset = server_web_datetime - server_web_datetime_utc
+        server_utc_datetime = server_db_datetime - server_utc_offset
+
+        return server_utc_datetime.replace(tzinfo=pytz.timezone('UTC'))
+
+    def _getActualBugId(self, bug_id):
+        """Return the actual bug id for an alias or id."""
+        # See if bug_id is actually an alias.
+        actual_bug_id = self._bug_aliases.get(bug_id)
+
+        # bug_id isn't an alias, so try turning it into an int and
+        # looking the bug up by ID.
+        if actual_bug_id is not None:
+            return actual_bug_id
+        else:
+            try:
+                actual_bug_id = int(bug_id)
+            except ValueError:
+                # If bug_id can't be int()'d then it's likely an alias
+                # that doesn't exist, so raise BugNotFound.
+                raise BugNotFound(bug_id)
+
+            # Check that the bug does actually exist. That way we're
+            # treating integer bug IDs and aliases in the same way.
+            if actual_bug_id not in self._bugs:
+                raise BugNotFound(bug_id)
+
+            return actual_bug_id
+
+    def _getBugIdsToRetrieve(self, bug_ids):
+        """For a set of bug IDs, return those for which we have no data."""
+        bug_ids_to_retrieve = []
+        for bug_id in bug_ids:
+            try:
+                actual_bug_id = self._getActualBugId(bug_id)
+            except BugNotFound:
+                bug_ids_to_retrieve.append(bug_id)
+
+        return bug_ids_to_retrieve
+
+    def initializeRemoteBugDB(self, bug_ids):
+        """See `IExternalBugTracker`."""
+        # First, discard all those bug IDs about which we already have
+        # data.
+        bug_ids_to_retrieve = self._getBugIdsToRetrieve(bug_ids)
+
+        # Pull the bug data from the remote server. permissive=True here
+        # prevents Bugzilla from erroring if we ask for a bug it doesn't
+        # have.
+        response_dict = self.xmlrpc_proxy.Bug.get({
+            'ids': bug_ids_to_retrieve,
+            'permissive': True,
+            })
+        remote_bugs = response_dict['bugs']
+
+        self._storeBugs(remote_bugs)
+
 
 class BugzillaLPPlugin(BugzillaAPI):
     """An `ExternalBugTracker` to handle Bugzillas using the LP Plugin."""
@@ -472,18 +564,6 @@
             raise BugTrackerAuthenticationError(
                 self.baseurl, message)
 
-    def _storeBugs(self, remote_bugs):
-        """Store remote bugs in the local `bugs` dict."""
-        for remote_bug in remote_bugs:
-            self._bugs[remote_bug['id']] = remote_bug
-
-            # The bug_aliases dict is a mapping between aliases and bug
-            # IDs. We use the aliases dict to look up the correct ID for
-            # a bug. This allows us to reference a bug by either ID or
-            # alias.
-            if remote_bug['alias'] != '':
-                self._bug_aliases[remote_bug['alias']] = remote_bug['id']
-
     def getModifiedRemoteBugs(self, bug_ids, last_checked):
         """See `IExternalBugTracker`."""
         # We marshal last_checked into an xmlrpclib.DateTime since
@@ -538,12 +618,7 @@
         """See `IExternalBugTracker`."""
         # First, discard all those bug IDs about which we already have
         # data.
-        bug_ids_to_retrieve = []
-        for bug_id in bug_ids:
-            try:
-                actual_bug_id = self._getActualBugId(bug_id)
-            except BugNotFound:
-                bug_ids_to_retrieve.append(bug_id)
+        bug_ids_to_retrieve = self._getBugIdsToRetrieve(bug_ids)
 
         # Next, grab the bugs we still need from the remote server.
         # We pass permissive=True to ensure that Bugzilla won't error if
@@ -573,30 +648,6 @@
         server_utc_time = datetime(*server_timetuple[:6])
         return server_utc_time.replace(tzinfo=pytz.timezone('UTC'))
 
-    def _getActualBugId(self, bug_id):
-        """Return the actual bug id for an alias or id."""
-        # See if bug_id is actually an alias.
-        actual_bug_id = self._bug_aliases.get(bug_id)
-
-        # bug_id isn't an alias, so try turning it into an int and
-        # looking the bug up by ID.
-        if actual_bug_id is not None:
-            return actual_bug_id
-        else:
-            try:
-                actual_bug_id = int(bug_id)
-            except ValueError:
-                # If bug_id can't be int()'d then it's likely an alias
-                # that doesn't exist, so raise BugNotFound.
-                raise BugNotFound(bug_id)
-
-            # Check that the bug does actually exist. That way we're
-            # treating integer bug IDs and aliases in the same way.
-            if actual_bug_id not in self._bugs:
-                raise BugNotFound(bug_id)
-
-            return actual_bug_id
-
     def getRemoteStatus(self, bug_id):
         """See `IExternalBugTracker`."""
         actual_bug_id = self._getActualBugId(bug_id)
 
=== modified file 'lib/lp/bugs/tests/bugzilla-xmlrpc-transport.txt'
--- lib/lp/bugs/tests/bugzilla-xmlrpc-transport.txt	2009-08-18 16:39:17 +0000
+++ lib/lp/bugs/tests/bugzilla-xmlrpc-transport.txt	2009-08-21 09:32:57 +0000
@@ -576,3 +576,68 @@
     Traceback (most recent call last):
       ...
     Fault: <Fault 300: 'The username or password you entered is not valid.'>
+
+
+Getting the current time
+------------------------
+
+The Bugzilla.time() method allows us to retrieve a dict of the time on
+the remote server.
+
+    >>> time_dict = server.Bugzilla.time()
+    >>> for key in sorted(time_dict):
+    ...     print "%s: %s" % (key, time_dict[key])
+    db_time: 20080501T01:01:01
+    tz_name: UTC
+    tz_offset: +0000
+    tz_short_name: UTC
+    web_time: 20080501T01:01:01
+    web_time_utc: 20080501T01:01:01
+
+If the remote server is in a different timezone, the db_time and
+web_time items will be in the server's local timezone whilst
+web_time_utc will be in UTC.
+
+    >>> bugzilla_transport.utc_offset = 60**2
+    >>> bugzilla_transport.timezone = 'CET'
+    >>> time_dict = server.Bugzilla.time()
+    >>> for key in sorted(time_dict):
+    ...     print "%s: %s" % (key, time_dict[key])
+    db_time: 20080501T01:01:01
+    tz_name: CET
+    tz_offset: +0100
+    tz_short_name: CET
+    web_time: 20080501T01:01:01
+    web_time_utc: 20080501T00:01:01
+
+
+Getting bugs from the server
+----------------------------
+
+The Bugzilla API method Bug.get() allows us to get one or more bugs from
+the remote server. It takes a list of bug IDs to return and returns a
+list of dicts containing those bugs' data.
+
+    >>> return_value = server.Bug.get(
+    ...     {'ids': [1], 'permissive': True})
+    >>> [bug_dict] = return_value['bugs']
+    >>> for key in sorted(bug_dict):
+    ...     print "%s: %s" % (key, bug_dict[key])
+    alias: 
+    assigned_to: [e-mail]
+    component: GPPSystems
+    creation_time: 20080610T16:19:53
+    id: 1
+    internals:...
+    is_open: True
+    last_change_time: 20080610T16:19:53
+    priority: P1
+    product: Marvin
+    resolution: FIXED
+    severity: normal
+    status: RESOLVED
+    summary: That bloody robot still exists.
+
+Note that further tests for this functionality can be found in the
+"Launchpad.get_bugs()" section, above. This is because these two methods
+are synonymous.
 
=== modified file 'lib/lp/bugs/tests/externalbugtracker.py'
--- lib/lp/bugs/tests/externalbugtracker.py	2009-08-18 16:41:18 +0000
+++ lib/lp/bugs/tests/externalbugtracker.py	2009-08-21 09:32:57 +0000
@@ -522,7 +522,9 @@
         # what BugZilla will return.
         local_time = xmlrpclib.DateTime(local_datetime.timetuple())
 
-        utc_date_time = local_datetime - timedelta(seconds=self.utc_offset)
+        utc_offset_delta = timedelta(seconds=self.utc_offset)
+        utc_date_time = local_datetime - utc_offset_delta
+
         utc_time = xmlrpclib.DateTime(utc_date_time.timetuple())
         return {
             'local_time': local_time,
@@ -757,7 +759,11 @@
 
     # Map namespaces onto method names.
     methods = {
-        'Bugzilla': ['version'],
+        'Bug': ['get'],
+        'Bugzilla': [
+            'time',
+            'version',
+            ],
         'Test': ['login_required'],
         'User': ['login'],
         }
@@ -794,6 +800,29 @@
                     300,
                     "The username or password you entered is not valid.")
 
+    def time(self):
+        """Return a dict of the local time and associated data."""
+        # We cheat slightly by calling the superclass to get the time
+        # data. We do this the old fashioned way because XML-RPC
+        # Transports don't support new-style classes.
+        time_dict = TestBugzillaXMLRPCTransport.time(self)
+        offset_hours = (self.utc_offset / 60) / 60
+        offset_string = '+%02d00' % offset_hours
+
+        return {
+            'db_time': time_dict['local_time'],
+            'tz_name': time_dict['tz_name'],
+            'tz_offset': offset_string,
+            'tz_short_name': time_dict['tz_name'],
+            'web_time': time_dict['local_time'],
+            'web_time_utc': time_dict['utc_time'],
+            }
+
+    def get(self, arguments):
+        """Return a list of bug dicts for a given set of bug ids."""
+        # This method is actually just a synonym for get_bugs().
+        return self.get_bugs(arguments)
+
 
 class TestMantis(Mantis):
     """Mantis ExternalSystem for use in tests.