[imapfilter-devel] IMAP IDLE vs become_daemon

[Paul]

Hello,

I'd like to hear how people have approached the main loop for imapfilter 
(if they have).  Currently I do in-and-out jobs with imapfilter, and 
trigger them via cron.   However, I want to get more complex and 
daemonise what I am doing and have it run forever.

So become_daemon can effectively replace cron, by calling a function 
periodically.  My first question is, if I set the polling to be, for 
example, 45 seconds, and the function I call for some reason takes 
several minutes to run, what happens?  Would I end up with several 
processes running concurrently trying to achieve the same thing?

My second question is about imap idle.

Lets say I have, psuedo code:

   repeat
     recent, exists, unseen = account:INBOX:get_status()
     process_my_inbox()
     update = enter_idle(account.INBOX)
   until 1=0

So I want to continually monitor my inbox and process whenever something 
happens.  What would be the best way to daemonise this?  Or would it be 
best not to?  I have a series of mailboxes I want to monitor so would I 
have a series of functions that monitor each mailbox, and then daemonise 
each one with an arbitrarily big interval?

Lastly, and this is more of a logic question, if the process_my_inbox 
gathers a whole bunch of mail from INBOX (say select_all()), and then 
does various things to it, which takes time, and I return from that 
function to enter_idle once more, presumably if anything has changed in 
the mailbox in between my function doing the select_all and exiting the 
function, this won't be seen by enter_idle - it would have happened 
before idle was called.  So should the "process_my_inbox" function be 
wrapped in its own loop where I check for status changes at the end of 
the processing to see whether it needs to go back in, or whether it is 
appropriate to enter_idle because nothing has changed?

Thanks for any help.  I have read David DeSimone's explanation of his 
approach, and he seems to do some of the things I am talking about here.

Paul