= Pushing comments to external bugtrackers =

Some ExternalBugTrackers support the pushing of comments from Launchpad
to the remote bug tracker.

In order to demonstrate this we need to create example Bug, BugTracker,
BugWatch, Message and BugMessage instances with which to work.

    >>> from zope.interface import implements
    >>> from canonical.config import config
    >>> from lp.bugs.tests.externalbugtracker import (
    ...     new_bugtracker)
    >>> from lp.services.messages.interfaces.message import IMessageSet
    >>> from canonical.testing.layers import LaunchpadZopelessLayer
    >>> from lp.bugs.interfaces.bug import CreateBugParams
    >>> from lp.bugs.interfaces.bugmessage import IBugMessageSet
    >>> from lp.bugs.interfaces.bugtracker import BugTrackerType
    >>> from lp.bugs.interfaces.bugwatch import IBugWatchSet
    >>> from lp.registry.interfaces.person import IPersonSet
    >>> from lp.registry.interfaces.product import IProductSet

    >>> bug_tracker = new_bugtracker(BugTrackerType.TRAC)

    >>> LaunchpadZopelessLayer.switchDbUser('launchpad')
    >>> sample_person = getUtility(IPersonSet).getByEmail(
    ...     'test@canonical.com')
    >>> firefox = getUtility(IProductSet).getByName('firefox')
    >>> bug = firefox.createBug(
    ...     CreateBugParams(sample_person, "A test bug",
    ...         "With a test description.",
    ...         subscribe_owner=False))

    >>> message = getUtility(IMessageSet).fromText(
    ...     "An example comment", "Pushing, for the purpose of.",
    ...     sample_person)

    >>> bug_watch = bug.addWatch(bug_tracker, '1234', sample_person)

    >>> transaction.commit()

    >>> LaunchpadZopelessLayer.switchDbUser(config.checkwatches.dbuser)
    >>> bug_watch = getUtility(IBugWatchSet).get(bug_watch.id)
    >>> bug_message = bug.linkMessage(message, bug_watch)

The ISupportsCommentPushing interface defines one method that an
ExternalBugTracker must support in order to be able to push comments to
remote systems. That method is the addRemoteComment() method.

In order to test the pushing of comments to remote systems we'll create
an example ExternalBugTracker that implements the
ISupportsCommentPushing interface.

    >>> from lp.bugs.interfaces.externalbugtracker import ISupportsCommentPushing
    >>> from lp.bugs.externalbugtracker import (
    ...     ExternalBugTracker)

    >>> class CommentPushingExternalBugTracker(ExternalBugTracker):
    ...     implements(ISupportsCommentPushing)
    ...
    ...     next_comment_id = 1
    ...     remote_comments = {}
    ...
    ...     def addRemoteComment(self, remote_bug, comment_body, rfc822msgid):
    ...         remote_comment_id = str(self.next_comment_id)
    ...         self.remote_comments[remote_comment_id] = comment_body
    ...
    ...         print "Comment added as remote comment %s" % (
    ...             remote_comment_id)
    ...
    ...         self.next_comment_id += 1
    ...         return remote_comment_id

    >>> external_bugtracker = CommentPushingExternalBugTracker(
    ...     'http://example.com/')

    >>> ISupportsCommentPushing.providedBy(external_bugtracker)
    True

The comment attached to the bug currently does not have its
remote_comment_id set.  This is because it originated in Launchpad and
has not yet been pushed to the remote bugtracker.

    >>> print bug_message.remote_comment_id is None
    True

The IBugWatch interface defines a property, unpushed_comments, which
is a set of the BugMessages on a BugWatch that need to be pushed to the
remote server.

    >>> comments = [
    ...     comment.message.text_contents
    ...     for comment in bug_watch.unpushed_comments]
    >>> print comments
    [u'Pushing, for the purpose of.']

The CheckwatchesMaster method pushBugComments() is responsible for
calling the addRemoteComment() method of ISupportsCommentPushing for
each Launchpad comment that needs to be pushed to the remote bug
tracker.

    >>> from lp.services.scripts.logger import log
    >>> from lp.bugs.scripts.checkwatches.core import CheckwatchesMaster
    >>> from lp.bugs.scripts.checkwatches.tests.test_bugwatchupdater import (
    ...     make_bug_watch_updater)

    >>> bugwatch_updater = make_bug_watch_updater(
    ...     CheckwatchesMaster(transaction), bug_watch,
    ...     external_bugtracker)

    >>> bugwatch_updater.pushBugComments()
    Comment added as remote comment 1
    INFO:...:Pushed 1 comments to remote bug 1234 on ...

The comment that we pushed to the remote bug will now have a
remote_comment_id.

    >>> def print_bug_messages(bug, bug_watch):
    ...     for message in bug.messages[1:]:
    ...         bug_message = getUtility(IBugMessageSet).getByBugAndMessage(
    ...             bug, message)
    ...         print "%s: %s" % (
    ...             bug_message.remote_comment_id,
    ...             bug_message.message.text_contents)
    >>> print_bug_messages(bug, bug_watch)
    1: Pushing, for the purpose of.

If we try to push the comment again, nothing will happen because we
already have a remote id for it (ergo it has been pushed already).

    >>> transaction.commit()

    >>> bugwatch_updater.pushBugComments()
    >>> transaction.commit()

If we now check the bug watch's unpushed_comments property, we will
find it to be empty.

    >>> print list(bug_watch.unpushed_comments)
    []

If more comments are added to the bug they will be pushed to the remote
tracker the next time the bugwatch updater accesses it.

    >>> LaunchpadZopelessLayer.switchDbUser('launchpad')
    >>> message_two = getUtility(IMessageSet).fromText(
    ...     "Comment the second", "Body the second.", sample_person)

    >>> message_three = getUtility(IMessageSet).fromText(
    ...     "Comment the third", "Body the third.", sample_person)
    >>> transaction.commit()

    >>> LaunchpadZopelessLayer.switchDbUser(config.checkwatches.dbuser)
    >>> bug_watch = getUtility(IBugWatchSet).get(bug_watch.id)
    >>> bugmessage_two = bug.linkMessage(message_two, bug_watch)
    >>> bugmessage_three = bug.linkMessage(message_three, bug_watch)
    >>> transaction.commit()

    >>> bugwatch_updater.pushBugComments()
    Comment added as remote comment 2
    Comment added as remote comment 3
    INFO:...:Pushed 2 comments to remote bug 1234 on ...

    >>> print_bug_messages(bug, bug_watch)
    1: Pushing, for the purpose of.
    2: Body the second.
    3: Body the third.

    >>> transaction.commit()

If a comment on the Launchpad bug isn't related to the bug watch, it
won't be pushed.

    >>> LaunchpadZopelessLayer.switchDbUser('launchpad')
    >>> message_four = getUtility(IMessageSet).fromText(
    ...     "Comment the fourth", "Body the fourth.", sample_person)
    >>> transaction.commit()
    >>> LaunchpadZopelessLayer.switchDbUser(config.checkwatches.dbuser)
    >>> bugmessage_four = bug.linkMessage(message_four)
    >>> transaction.commit()

    >>> bugwatch_updater.pushBugComments()

    >>> print_bug_messages(bug, bug_watch)
    1: Pushing, for the purpose of.
    2: Body the second.
    3: Body the third.
    None: Body the fourth.

The bug watch updater won't try to push comments that have been imported
from the remote bugtracker. To demonstrate this, we need to create an
example ExternalBugTracker that does comment importing.

    >>> from lp.bugs.interfaces.externalbugtracker import ISupportsCommentImport
    >>> class CommentImportingExternalBugTracker(
    ...     CommentPushingExternalBugTracker):
    ...     implements(ISupportsCommentImport)
    ...
    ...     external_comment_dict = {
    ...         '4': "External comment 1.",
    ...         '5': "External comment 2.",
    ...         '6': "External comment 3."}
    ...
    ...     poster_tuple = ("Test Person", "test@example.com")
    ...
    ...     def fetchComments(self, bug_watch, comment_ids):
    ...         pass
    ...
    ...     def getCommentIds(self, bug_watch):
    ...         return sorted(self.external_comment_dict.keys())
    ...
    ...     def getPosterForComment(self, bug_watch, comment_id):
    ...         """Return a tuple of (displayname, email)."""
    ...         return self.poster_tuple
    ...
    ...     def getMessageForComment(self, bug_watch, comment_id, poster):
    ...         """Return a Message object for a comment."""
    ...         message = getUtility(IMessageSet).fromText(
    ...             "Some subject or other",
    ...             self.external_comment_dict[comment_id], owner=poster,
    ...             rfc822msgid=comment_id)
    ...         return message

    >>> external_bugtracker = CommentImportingExternalBugTracker(
    ...     'http://example.com/')

Running importBugComments() on the external bugtracker will result in
the remote comments being imported into Launchpad.

    >>> transaction.commit()

    >>> bugwatch_updater.external_bugtracker = external_bugtracker
    >>> bugwatch_updater.importBugComments()
    INFO:...:Imported 3 comments for remote bug 1234 on ...

Each of the imported comments has its remote_comment_id field set.

    >>> print_bug_messages(bug, bug_watch)
    1: Pushing, for the purpose of.
    2: Body the second.
    3: Body the third.
    None: Body the fourth.
    4: External comment 1.
    5: External comment 2.
    6: External comment 3.

Running pushBugComments() on the external bugtracker won't result in the
comments being pushed because they have already been imported.

    >>> bugwatch_updater.pushBugComments()

If the external bugtracker's addRemoteComment() method returns an
invalid remote comment ID, an error will be raised:

    >>> class ErroringExternalBugTracker(CommentPushingExternalBugTracker):
    ...     def addRemoteComment(self, remote_bug, comment_body, rfc822msgid):
    ...         print "Pretending to add a comment to bug %s" % remote_bug
    ...         return None

    >>> LaunchpadZopelessLayer.switchDbUser('launchpad')
    >>> message_five = getUtility(IMessageSet).fromText(
    ...     "Comment the fifth", "Body the fifth.", sample_person)
    >>> transaction.commit()

    >>> LaunchpadZopelessLayer.switchDbUser(config.checkwatches.dbuser)
    >>> bug_watch = getUtility(IBugWatchSet).get(bug_watch.id)
    >>> bugmessage_five = bug.linkMessage(message_five, bug_watch)
    >>> transaction.commit()

    >>> broken_external_bugtracker = ErroringExternalBugTracker(
    ...     'http://example.com')

    >>> bugwatch_updater = make_bug_watch_updater(
    ...     CheckwatchesMaster(transaction), bug_watch,
    ...     external_bugtracker)
    >>> bugwatch_updater.external_bugtracker = broken_external_bugtracker
    >>> bugwatch_updater.pushBugComments()
    Traceback (most recent call last):
      ...
    AssertionError: A remote_comment_id must be specified.


== Formatting pushed comments ==

The comments that have been pushed to the remote bugtracker have been
formatted to include data about the comment in Launchpad.

    >>> remote_comments = external_bugtracker.remote_comments
    >>> for remote_comment_id in sorted(remote_comments.keys()):
    ...     print remote_comments[remote_comment_id]
    ...     print "--------------------"
    Sample Person added the following comment to Launchpad bug report...:
    <BLANKLINE>
    Pushing, for the purpose of.
    <BLANKLINE>
    --
    http://launchpad.net/bugs/...
    <BLANKLINE>
    --------------------
    Sample Person added the following comment to Launchpad bug report...:
    <BLANKLINE>
    Body the second.
    <BLANKLINE>
    --
    http://launchpad.net/bugs/...
    <BLANKLINE>
    --------------------
    Sample Person added the following comment to Launchpad bug report...:
    <BLANKLINE>
    Body the third.
    <BLANKLINE>
    --
    http://launchpad.net/bugs/...
    <BLANKLINE>
    --------------------

The CheckwatchesMaster class has a method, _formatRemoteComment() which
will take a Launchpad comment and format it ready for uploading to the
remote server. This allows us to include salient information, such as
the comment author, with the pushed comment.

    >>> formatted_message = bugwatch_updater._formatRemoteComment(message)
    >>> print formatted_message
    Sample Person added the following comment to Launchpad bug report...:
    <BLANKLINE>
    Pushing, for the purpose of.
    <BLANKLINE>
    -- 
    http://launchpad.net/bugs/...
    <BLANKLINE>

The template used to format the comments can be changed by altering the
external bugtracker's comment_template attribute.

    >>> from os.path import dirname, join

    >>> original_comment_template = external_bugtracker.comment_template
    >>> comment_template = join(
    ...     dirname(__file__), '../tests/testfiles/test_comment_template.txt')
    >>> external_bugtracker.comment_template = comment_template

    >>> bugwatch_updater.external_bugtracker = external_bugtracker
    >>> formatted_message = bugwatch_updater._formatRemoteComment(message)
    >>> print formatted_message
    Egg and bacon
    Egg, sausage and bacon
    Egg, bacon and bug #...
    Egg, bacon, sausage and Sample Person
    Pushing, for the purpose of.
    <BLANKLINE>

    >>> external_bugtracker.comment_template = original_comment_template