Re: Daemonizing CRM114 using FIFO

On Mon, Sep 22, 2008 at 11:22:39PM +0200, Ger Hobbelt wrote:

ok, that's the not too short answer :) 

> (a) is 'delineating' a message - the 'end of message' marker. Two

let's stress that this can be done at script level, using all the tricks
and tools in your *ix box. Eg I used a couple of md5sum as markers - that's
string matching, easy with crm114.
The hard thing is dealing with buffered I/O: there's no good way around it 
except do proper timing, which makes your daemonizing effort nonsense.
So you need to feed the stream with start/end markers and crm needs to loop
on INPUT and rely on such markers, not on EOF.

> (b) Which leaves the second issue, which you already ran into and
> resolved by open+close on the one side plus wait on the other: this is

yep, and see above - you gain nothing except an headache, unless you've got
a *very* complex .crm script; if your script is like sample you post, you
are better off doing the usual 1 crm invocation per msg.

ATM INPUT doesn't provide the proper IOCTL flags to deal properly with pipe
like PERL does; if you feel like hacking the INPUT statement, check what 
others have done, like on-screen daemon (onscreend, sorry don't have URL
handy) and CLAMAV (both the FIFO and protocol stuff).

For both async/sync cases, try to hack to your taste the following sample:

!window
!{
!  isolate (:content:) //
!  isolate (:z:) //
!  isolate (:x:) /0/
!  :loop:
!  { input [/tmp/dynamic_fifo]
!    { match (:: :z:) /(.*)\n=>FINE<=\n/
!      eval (:x:) /:#:_dw:/
!      #output /:_dw: :*:x: /
!      alter (:content:) /:*:content::*:z:/
!      goto /:do_it:/
!    }
!    alter (:content:) /:*:content::*:_dw:/
!    liaf
!  }
!  goto /:loop:/
!  :do_it:
!  eval (:x:) /:#:content:/    
!  classify <osb unique microgroom> \
!       (A.css B.css C.css D.css) (:_dw:) [:content:]
!  output /:*:x:\n/
!  #output /:*:_dw:\n\n/
!  alter (:content:) //
!  alter (:z:) //
!  alter (:_dw:) //
!  goto /:loop:/
!  exit
!}
!

which you'd start like

! crm -e /tmp/dynamic.crm &

then you'd feed the FIFO like

! for f in $list;do
!   { cat "$f"; printf "\n=>FINE<=\n"; } > /tmp/dynamic_fifo
! done

HTH
-- 
paolo

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