dovecot - Feb 2006 - Programming Help

Hi, 

 I was hoping you could provide me with some pointers on how to get started
adding some features to dovecot.

 

What I am trying to do is add an optional publish mechanism, that would
publish a list of events as they occur, so that an external program could
read these events and do "something".

These events would be "Add", "Delete", "Move" -
these would be posted every
time a new message is added, deleted or moved.

   "CreateDir", "DeleteDir" would be published when a user
creates a
subf-folder or removes one.

 

 

A simple example would be to configure the system to publish 'Add
Message'
events, and then an external program would read these, and send a
notification event to web based users who are currently logged in.

 

The publish feature would be controlled by the config file, and would be
disabled by default

The config setting would allow an administrator to specify what events to
publish, the mechanism to use, and optional arguments for the mechanism

 For mechanisms I plan on developing a file based system, one file per
event, written into a directory, the subscriber/reader would delete the file

 Other mechanisms could include TCP/IP based (connect to port XX, and send
some data); or even connect to a  commercial Message Queue product.

Ex.

Publish=ADD+DELETE+MOVE:file:/var/spool/imapevents

Or

Publish=ADD+DELETE+MOVE:tcpip:localhost:9999

 

 

 

It would help me a lot if you could just provide me with a few pointers as
to the best place to add my features into the dovecot code, I took a quick
look at the code and decided to contact you first before going ahead and
putting things in the WRONG place. I did see the code for supporting inotify
and similar mechanisms, but I don't see the big picture ? How does dovecot
use inotify ?, what features are enabled that you don't get without inotify.

 

If you have a code-roadmap, or architectural diagrams (or doodles) that
would be helpful too.

 

In terms of inotify, I don't think this will work for me, since I would like
to have the user, Message-Id and Imap UIDL sent in the event message

 

I hope this makes sense, if not just send me an email asking for
clarification.

 

All of the changes I make I will submit back to you, and hopefully they will
be made part of the base product.

 

Thanks,

 

Neal Katz

 

p.s. I chose Dovecot because I was very impressed with the ease of
installation and migration (from courier), my early tests have shown it to
be twice as fast when traverse all messages in a large mailbox ( 100K
message ).

 

 

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Neal Katz wrote:
> Hi, 
> 
>  I was hoping you could provide me with some pointers on how to get started
> adding some features to dovecot.
> 
Have you looked at the code yet?

 From my own experiences with writing code for Dovecot, I think you'll find
Timo
has done a brilliant job of keeping the code clean, clear, and well organised. 
It rarely takes much effort to work out which area of the code to investigate.

...meanwhile...

What you're proposing sounds interesting - I can certainly see the benefits
of
it.  Though, have you looked at D-Bus?  Perhaps worth considering.

--
Curtis Maloney
cmaloney at cardgate.net

On 8.2.2006 10:38, "Neal  Katz" <nak at iyago.com> wrote:
> Hi, 
>  I was hoping you could provide me with some pointers on how to get started
> adding some features to dovecot.
>  
> What I am trying to do is add an optional publish mechanism, that would
> publish a list of events as they occur, so that an external program could
read
> these events and do ?something?.
> These events would be ?Add?, ?Delete?, ?Move? ? these would be posted every
> time a new message is added, deleted or moved.
>    ?CreateDir?, ?DeleteDir? would be published when a user creates a
> subf-folder or removes one.
Sounds like this should be done by a plugin. You can hook into mail-storage
API to see the changes.

You could look as an example the plugins distributed with 1.0beta3. For
example quota plugin hooks into several places.
> It would help me a lot if you could just provide me with a few pointers as
to
> the best place to add my features into the dovecot code, I took a quick
look
> at the code and decided to contact you first before going ahead and putting
> things in the WRONG place. I did see the code for supporting inotify and
> similar mechanisms, but I don?t see the big picture ? How does dovecot use
> inotify ?, what features are enabled that you don?t get without inotify.
Inotify doesn't really matter. It would be just an optimization. You'd
probably want to hook into mail_storage->sync_next() to see the mail
additions/expunges.
> If you have a code-roadmap, or architectural diagrams (or doodles) that
would
> be helpful too.
Not currently, sorry. There is some out of date design docs in
doc/design.txt though..
> In terms of inotify, I don?t think this will work for me, since I would
like
> to have the user, Message-Id and Imap UIDL sent in the event message
In sync interface you can ask those from the mail.