***************
Email Interface
***************

Overview
========

The interactive email interface to Bugs Everywhere (BE) attempts to
provide a `Debian-bug-tracking-system-style`_ interface to a BE
repository.  Users can mail in bug reports, comments, or control
requests, which will be committed to the served repository.
Developers can then pull the changes they approve of from the served
repository into their other repositories and push updates back onto
the served repository.

.. _Debian-bug-tracking-system-style: http://www.debian.org/Bugs

Architecture
============

In order to reduce setup costs, the entire interface can piggyback on
an existing email address, although from a security standpoint it's
probably best to create a dedicated user.  Incoming email is filtered
by procmail, with matching emails being piped into ``be-handle-mail``
for execution.

Once ``be-handle-mail`` receives the email, the parsing method is
selected according to the subject tag that procmail used grab the
email in the first place.  There are four parsing styles:

    +--------------------+----------------------------------+
    | Style              | Subject                          |
    +====================+==================================+
    | creating bugs      | [be-bug:submit] new bug summary  |
    +--------------------+----------------------------------+
    | commenting on bugs | [be-bug:<bug-id>] commit message |
    +--------------------+----------------------------------+
    | control            | [be-bug] commit message          |
    +--------------------+----------------------------------+

These are analogous to ``submit@bugs.debian.org``,
``nnn@bugs.debian.org``, and ``control@bugs.debian.org`` respectively.

Creating bugs
=============

This interface creates a bug whose summary is given by the email's
post-tag subject.  The body of the email must begin with a
pseudo-header containing at least the ``Version`` field.  Anything after
the pseudo-header and before a line starting with ``--`` is, if present,
attached as the bug's first comment.::

    From jdoe@example.com Fri Apr 18 12:00:00 2008
    From: John Doe <jdoe@example.com>
    Date: Fri, 18 Apr 2008 12:00:00 +0000
    Content-Type: text/plain; charset=UTF-8
    Content-Transfer-Encoding: 8bit
    Subject: [be-bug:submit] Need tests for the email interface.
    
    Version: XYZ
    Severity: minor
    
    Someone should write up a series of test emails to send into
    be-handle-mail so we can test changes quickly without having to
    use procmail.
    
    --
    Goofy tagline not included.

Available pseudo-headers are ``Version``, ``Reporter``, ``Assign``,
``Depend``, ``Severity``, ``Status``, ``Tag``, and ``Target``.

Commenting on bugs
==================

This interface appends a comment to the bug specified in the subject
tag.  The the first non-multipart body is attached with the
appropriate content-type.  In the case of ``text/plain`` contents,
anything following a line starting with ``--`` is stripped.::

    From jdoe@example.com Fri Apr 18 12:00:00 2008
    From: John Doe <jdoe@example.com>
    Date: Fri, 18 Apr 2008 12:00:00 +0000
    Content-Type: text/plain; charset=UTF-8
    Content-Transfer-Encoding: 8bit
    Subject: [be-bug:XYZ] Isolated problem in baz()
    
    Finally tracked it down to the bar() call.  Some sort of
    string<->unicode conversion problem.  Solution ideas?
    
    --
    Goofy tagline not included.

Controlling bugs
================

This interface consists of a list of allowed be commands, with one
command per line.  Blank lines and lines beginning with ``#`` are
ignored, as well anything following a line starting with ``--``.  All
the listed commands are executed in order and their output returned.
The commands are split into arguments with the POSIX-compliant
shlex.split().::

    From jdoe@example.com Fri Apr 18 12:00:00 2008
    From: John Doe <jdoe@example.com>
    Date: Fri, 18 Apr 2008 12:00:00 +0000
    Content-Type: text/plain; charset=UTF-8
    Content-Transfer-Encoding: 8bit
    Subject: [be-bug] I'll handle XYZ by release 1.2.3
    
    assign XYZ "John Doe <jdoe@example.com>"
    status XYZ assigned
    severity XYZ critical
    target XYZ 1.2.3
    
    --
    Goofy tagline ignored.

Example emails
==============

Take a look at ``interfaces/email/interactive/examples`` for some
more examples.

Procmail rules
==============

The file ``_procmailrc`` as it stands is fairly appropriate for as a
dedicated user's ``~/.procmailrc``.  It forwards matching mail to
``be-handle-mail``, which should be installed somewhere in the user's
path.  All non-matching mail is dumped into ``/dev/null``.  Everything
procmail does will be logged to ``~/be-mail/procmail.log``.

If you're piggybacking the interface on top of an existing account,
you probably only need to add the ``be-handle-mail`` stanza to your
existing ``~/.procmailrc``, since you will still want to receive
non-bug emails.

Note that you will probably have to add a::

    --repo /path/to/served/repository

option to the ``be-handle-mail`` invocation so it knows what repository to
serve.

Multiple repositories may be served by the same email address by adding
multiple ``be-handle-mail`` stanzas, each matching a different tag, for
example the ``[be-bug`` portion of the stanza could be ``[projectX-bug``,
``[projectY-bug``, etc.  If you change the base tag, be sure to add a::

    --tag-base "projectX-bug"

or equivalent to your ``be-handle-mail`` invocation.

Testing
=======

Send test emails in to ``be-handle-mail`` with something like::

    cat examples/blank | ./be-handle-mail -o -l - -a
