[AWIPS #MXP-719134]: EDEX and "traditional" LDM

> Last fall, I did an install of EDEX on a new server. Unfortunately, it 
> stomped all over the "traditional" LDM we were running to supply data for 
> Gempak and IDV. So, not wanting to break ongoing uses of the data, I backed 
> it out and got the olf LDM processes running again.

This may have been when the AWIPS LDM client was being installed to 
/usr/local/ldm like it is with GEMPAK or TDS.  I've since moved the install to 
/awips2/ldm and the "awips:fxalpha" user owns and runs ldmadmin (though the 
service can be started and stopped with "edex start", or manually as "service 
edex_ldm start"

So it's possible to have two versions of the LDM installed, but either will 
work for either GEMPAK/TDS or AWIPS. But there is a catch:

* EDEX will not wait around for the entire file to be written before ingesting, 
e.g. for TDS, the pattern action

NGRID   ^[LM].B... KWBE ([0-3][0-9])([0-2][0-9]).*NAM_84/#218
        FILE
        
data/pub/native/grid/NCEP/NAM/CONUS_12km/NAM_CONUS_12km_(\1:yyyy)(\1:mm)\1_\200.grib2

will append incoming messages onto the same file.  Writing this for EDEX will 
cause the same file to be ingested multiple times, each subsequent time 
resulting in more and more duplication errors, using resources and slowing the 
entire system.

for EDEX each grib message is written individually and each record is processed 
as is comes in:

NGRID  ^[LM].B... KWBE ...... 
!grib2/[^/]*/([^/]*)/#([^/]*)/([0-9]{8})([0-9]{4})(F[0-9]{3})/([^/]*)
       FILE    -edex -log
       /awips2/data_store/grid/NAM12/NAM_CONUS_12km_\1_\3_\4Z_\5_\6-(seq).grib2



> 
> 1)      What is the best way to serve Gempak/IDV and EDEX on a single server?

I recommend using awips2-ldm installed in /awips2/ldm/ and adding a separate 
pqact file for data which you want to handle outside of EDEX (file to disk or 
using decoders). It's very simple:


* I copied pqact.gempak created by $NAWIPS/ldm/etc/gen_pqact.sh to 
/awips2/ldm/etc/
* in ldmd.conf I changed

EXEC    "pqact -e"

to

EXEC    "pqact -e /awips2/ldm/etc/pqact.conf"
EXEC    "pqact -f IDS-DDPLUS /awips2/ldm/etc/pqact.gempak"

then ran "ldmadmin restart" (as user awips).  Then you can follow the EDEX 
ingest with "edex log", and tail the decoder logs in 
/awips2/ldm/data/data/gempak/logs/.

The key to using multiple EXEC pqact entries with AWIPS2 LDM is to only have a 
single file for EDEX (only one file should be used with the -e flag  in "pqact 
-e").  

The "-e" flag is built into recent non-AWIPS releases of the LDM, so if you 
built from source, and have it installed in /usr/local/ldm, you can copy the 
AWIPS pqact.conf to /usr/local/ldm/etc and make the above edit to ldmd.conf and 
run it all from there.  Just be sure that both the "ldm:group" and 
"awips:fxalpha" users can read and write to /awips2/data_store/.



Ticket Details
===================
Ticket ID: MXP-719134
Department: Support AWIPS
Priority: Normal
Status: Open