~launchpad-pqm/launchpad/devel

The Spec Mail Exploder
======================

There's an address, notifications@specs.launchpad.net, which looks at
all incoming email to see if it looks like a change notifications from a
Moin wiki. If it receive such notification, it will look up the relevant
Launchpad specification, and re-send the mail to the spec's related
people.

First, let's take a look at how a Moin change notification looks like:

    >>> from canonical.launchpad.mail.ftests import read_test_message
    >>> moin_change = read_test_message('moin-change.txt')

It contains some headers, which are of no use to us, and the body is
base64 encoded.

    >>> print str(moin_change) #doctest: -NORMALIZE_WHITESPACE
    From webmaster@ubuntu.com Mon Mar 20 10:31:59 2006
    Return-path: <webmaster@ubuntu.com>
    Content-Type: text/plain; charset="utf-8"
    MIME-Version: 1.0
    Content-Transfer-Encoding: base64
    From: Launchpad Wiki <webmaster@ubuntu.com>
    To: Launchpad Wiki <webmaster@ubuntu.com>
    Date: Mon, 20 Mar 2006 10:26:28 -0000
    Message-ID: <20060320102628.17391.34951@palmer.ubuntu.com>
    Subject: [Launchpad Wiki] Update of "MediaIntegrityCheck" by ...
    Status: RO
    Content-Length: 1220
    <BLANKLINE>
    RGVhciBXaWtpIHVzZXIsDQo...

Let's take a look at the decode body, since we'll have to use it in
order to extract any useful information about the wiki page.

    >>> print moin_change.get_payload(decode=True)
    Dear Wiki user,
    <BLANKLINE>
    You have subscribed to a wiki page or wiki category on "Ubuntu Wiki"
    for change notification.
    <BLANKLINE>
    The following page has been changed by JamesHenstridge:
    https://wiki.ubuntu.com/MediaIntegrityCheck
    <BLANKLINE>
    The comment on the change is:
    A comment about the change
    <BLANKLINE>
    -----------------------------------------------------------------...
    ...


The Mail Handler
----------------

The mail handler that handles mail on notifications@specs.launchpad.net
is BlueprintHandler.

    >>> from canonical.config import config
    >>> from lp.services.mail.handlers import mail_handlers
    >>> handler = mail_handlers.get(config.launchpad.specs_domain)
    >>> handler is not None
    True

It has a helper method to help associate a URL with a specification. We
use this method instead of simply ISpecificationSet.getByURL() since the
Ubuntu wikis are special, they have more than one domain name mapping to
the same wiki. So if we start with the correct URL, of course we get the
specification with that URL.

    >>> spec = handler._getSpecByURL(
    ...     'https://wiki.ubuntu.com/MediaIntegrityCheck')
    >>> spec.specurl
    u'https://wiki.ubuntu.com/MediaIntegrityCheck'

But if someone would edit the same wiki page on wiki.edubuntu.org, we
would want the same spec's subscribers to be notified about it.

    >>> spec = handler._getSpecByURL(
    ...     'https://wiki.edubuntu.org/MediaIntegrityCheck')
    >>> spec.specurl
    u'https://wiki.ubuntu.com/MediaIntegrityCheck'

And the same with wiki.kubuntu.org URLs.

    >>> spec = handler._getSpecByURL(
    ...     'https://wiki.kubuntu.org/MediaIntegrityCheck')
    >>> spec.specurl
    u'https://wiki.ubuntu.com/MediaIntegrityCheck'

If no matching specification is found, None is returned.

    >>> spec = handler._getSpecByURL(
    ...     'https://wiki.kubuntu.org/NonExistant')
    >>> spec is None
    True

We use a logger to see what the handler does:

    >>> from canonical.launchpad.scripts import log
    >>> OLD_LOG_LEVEL = log._log.getEffectiveLevel()
    >>> log._log.setLevel(10)

Now, if we pass the email to it, we can see that it finds the correct
spec, and mails it to the related people.

    >>> handler.process(
    ...     moin_change, 'notifications@specs.launchpad.net', log=log)
    True

    >>> log._log.setLevel(OLD_LOG_LEVEL)

    >>> from lp.blueprints.interfaces.specification import ISpecificationSet
    >>> spec = getUtility(ISpecificationSet).getByURL(
    ...     'https://wiki.ubuntu.com/MediaIntegrityCheck')
    >>> spec.notificationRecipientAddresses()
    ['test@canonical.com']

Let's look at the email that got sent:

    >>> import transaction
    >>> from lp.services.mail import stub
    >>> transaction.commit()
    >>> len(stub.test_emails)
    1

The email got sent to all related people:

    >>> from_addr, to_addrs, raw_message = stub.test_emails.pop()
    >>> to_addrs == spec.notificationRecipientAddresses()
    True

We practically bounced the message, we didn't change anything about it,
except for setting the Sender header to our bounce address:

    >>> import email
    >>> sent_msg = email.message_from_string(raw_message)
    >>> sent_body = sent_msg.get_payload(decode=True)
    >>> sent_body == moin_change.get_payload(decode=True)
    True

    >>> sent_msg['To'] == moin_change['To']
    True

    >>> sent_msg['From'] == moin_change['From']
    True

    >>> sent_msg['Subject'] == moin_change['Subject']
    True

    >>> sent_msg['Sender'] == config.canonical.bounce_address
    True

If we get a change notification about a spec which doesn't exist in
Launchpad, nothing happens.

    >>> log._log.setLevel(10)
    >>> moin_change = read_test_message('moin-change-nonexistant.txt')
    >>> handler.process(
    ...     moin_change, 'notifications@specs.launchpad.net', log=log)
    True

    >>> print getUtility(ISpecificationSet).getByURL(
    ...     'https://wiki.ubuntu.com/NonExistant')
    None

In order to prevent loops, we set the X-Loop header:

    >>> sent_msg['X-Loop']
    'notifications@specs.launchpad.net'

So that if we someone re-sends the notification we sent to us, we'll
simply emit a warning and drop the email.

    >>> class FakeFileAlias:
    ...     http_url = 'http://librarian/foo.txt'
    >>> del sent_msg['Sender']
    >>> sent_msg['Sender'] = 'webmaster@ubuntu.com'
    >>> handler.process(
    ...     sent_msg, 'notifications@specs.launchpad.net',
    ...     filealias=FakeFileAlias(), log=log)
    WARNING...:Got back a notification we sent: http://librarian/foo.txt
    True

    >>> log._log.setLevel(OLD_LOG_LEVEL)

No emails were sent:

    >>> transaction.commit()
    >>> len(stub.test_emails)
    0

To prevent bad things happening if someone subscribes this address to
specifications for example, we ignore all email that are sent from
Launchpad:

    >>> del sent_msg['X-Loop']
    >>> del sent_msg['Sender']
    >>> sent_msg['Sender'] = config.canonical.bounce_address
    >>> log._log.setLevel(10)
    >>> handler.process(
    ...     sent_msg, 'notifications@specs.launchpad.net',
    ...     filealias=FakeFileAlias(), log=log)
    WARNING...:We received an email from Launchpad: http://librarian/foo.txt
    True

    >>> log._log.setLevel(OLD_LOG_LEVEL)

Again, no emails were sent:

    >>> transaction.commit()
    >>> len(stub.test_emails)
    0

Let's pass a notification from wiki.kubuntu.org regarding
MediaIntegrityCheck to see that the correct specification will be found,
and that the notification will be forwarded to the specification's
subscribers:

    >>> kubuntu_change = read_test_message('moin-change-kubuntu.txt')
    >>> log._log.setLevel(10)
    >>> handler.process(
    ...     kubuntu_change, 'notifications@specs.launchpad.net', log=log)
    True

    >>> log._log.setLevel(OLD_LOG_LEVEL)

    >>> transaction.commit()
    >>> len(stub.test_emails)
    1

    >>> from_addr, to_addrs, raw_message = stub.test_emails.pop()
    >>> to_addrs == spec.notificationRecipientAddresses()
    True

Lastly, let's simulate sending a moin notification, and use handleMail()
instead to ensure that handler above handles the email. This will make
sure that the handler is setup properly to handle unknown users, since
webmaster@ubuntu.com doesn't belong to any Person in Launchpad:

    >>> from lp.registry.interfaces.person import IPersonSet
    >>> getUtility(IPersonSet).getByEmail('webmaster@ubuntu.com') is None
    True

    >>> moin_change = read_test_message('moin-change.txt')
    >>> moin_change['X-Launchpad-Original-To'] = "notifications@%s" % (
    ...     config.launchpad.specs_domain)
    >>> moin_change['Sender'] = 'webmaster@ubuntu.com'

    >>> from lp.services.mail.incoming import handleMail
    >>> from lp.services.mail.sendmail import sendmail
    >>> sendmail(moin_change, bulk=False)
    '...'

    >>> transaction.commit()
    >>> handleMail()

    >>> transaction.commit()
    >>> len(stub.test_emails)
    1

    >>> from_addr, to_addrs, raw_message = stub.test_emails.pop()
    >>> to_addrs == spec.notificationRecipientAddresses()
    True

    >>> sent_msg = email.message_from_string(raw_message)
    >>> sent_msg['Message-Id'] == moin_change['Message-Id']
    True