[Mimedefang] Mysql connections

[Paul Murphy]

> I have only seen examples of opening and closing the connections inside of 
> filter_sender or filter_end. Is it possible to open a connection in 
> mimedefang when it starts up and close it on exit. I would like to insert 
> some information in a table from filter_relay, filter_sender and filter_end. 

You can do anything you want, as long as you open the connection in filter_initialize(), and close it in filter_cleanup() - from the man page:
 
       If  you  are  not  using  an  embedded Perl interpreter, then performing an action inside fil-
       ter_initialize is practically the same as performing it directly in the filter  file,  outside
       any  function  definition.   However, if you are using an embedded Perl interpreter, then any-
       thing you call directly from outside a function definition is executed once only in the parent
       process.   Anything in filter_initialize is executed once per slave.  If you use any code that
       opens a descriptor (for example, a connection to a database server), you must  run  that  code
       inside  filter_initialize and not directly from the filter, because the multiplexor closes all
       open descriptors when it activates a new slave.
 
       When a slave is about to exit, mimedefang.pl calls  the  function  filter_cleanup  (if  it  is
       defined)  with  no arguments.  This function can do whatever cleanup you like, such as closing
       file descriptors and cleaning up long-lived slave  resources.   The  return  value  from  fil-
       ter_cleanup becomes the slave's exit status.
 
However, you need to ensure that you either keep the database connection busy, or configure MySQL to not use any client timeouts, since it is prone to disconnecting clients after a while.  The result of this is that your slave dies, and the new slave gets a clean connection, so the mail will be delivered eventually, but you are introducing delays and potential problems as a result.
 
Best Wishes,

Paul. 
 
 
-- 

-------------------------------------------------------
Paul Murphy
Head of I.T.
Argenta Discovery
Tel. 01279 645 554
Fax. 01279 645 646