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20050509: logging script output via ldmd.conf exec command

Hi Angelo,

> To: <address@hidden>
> From: "Alvarez, Angelo CIV NAVPACMETOCCEN JTWC" <address@hidden>
> Subject: logging script output via ldmd.conf exec command
> Organization: > NAVPACMETOCCEN/JTWC
> Keywords: 200505032047.j43KlHP3009221

The above message contained the following:

> Aloha.  My ldmd.conf has the following line:
> exec    "/usr/ldm/scripts/Ingest.ksh >> /usr/ldm/logs/ingest/ingest.log"
> 
> Is this correct? I ask b/c the log file was not created when I =
> restarted ldm but was created when I run:
> 
> /usr/ldm/scripts/Ingest.ksh >> /usr/ldm/logs/ingest/ingest.log at the =
> command line.

The above didn't work because EXEC entries in the LDM
configuration-file, ldmd.conf, are executed via the execvp() system-call
-- which doesn't understand shell redirection syntax (e.g., ">>"). One
solution is to pass the pathname of the logfile to the script as an
argument, e.g.,

    exec        "/usr/ldm/scripts/Ingest.ksh /usr/ldm/logs/ingest/ingest.log"

The script can then append to the logfile.  For example, having the
following near the beginning of the script will redirect all
standard-output to the file named by the first argument:

    exec >> $1

If you, instead, wanted to redirect standard-error to that file, then
you could have

    exec 2>> $1

And if you wanted to redirect both the standard-output and standard-error
streams:

    exec >> $1 2>&1

> Also wanted to verify that my Ingest.ksh script is configured correctly =
> to work with LDM b/c not all of my pqinsert logs are updating as =
> expected.
> 
> Here is the source (note: all files are copied to a "backup" directory =
> just in case of problems):
> 
> #!/bin/ksh
> 
> input_dir=3D/comms_dir/ddn/fnoc/
> ls $input_dir
> echo "Input_Dir: $input_dir"
> GRIDLOG=3D/usr/ldm/logs/ingest/pqinsert.grid.log
> WMOLOG=3D/usr/ldm/logs/ingest/pqinsert.wmo.log
> NPOINTLOG=3D/usr/ldm/logs/ingest/pqinsert.npoint.log
> 
> cd ${input_dir}
> while [ 1 ]
> do
>    rm -f ${input_dir}/*BEGIN*
>    for arg in `ls -1`
>    do
>       prefix=3D`echo $arg | cut -c1-4`
>       prefix_grep=3D`echo $prefix | grep -i temp`
>       if [ "XX" !=3D "X${prefix_grep}X" ]
>       then
>        echo "$arg is still coming in, will skip over it for now.."
>       else
>        if [ "XX" !=3D "X`echo $arg | grep GR1`X" ]
>        then=20
>             #echo "NGRID GR1 $arg"
>            cp $arg /comms_dir/oldpsrfiles/$arg
>             pqinsert -l $GRIDLOG -f NGRID $arg
>             rm -f $arg
>        elif [ "XX" !=3D "X`echo $arg | grep IDY | grep grb`X" ]
>        then=20
>             #echo "NGRID GRB $arg"
>             cp $arg /comms_dir/oldpsrfiles/$arg
>             pqinsert -l $GRIDLOG -f NGRID $arg
>             rm -f $arg
>        elif [ "XX" !=3D "X`echo $arg | grep jgsm | grep grib`X" ]
>        then=20
>             #echo "NGRID GRIB $arg"
>             cp $arg /comms_dir/oldpsrfiles/$arg
>             pqinsert -l $GRIDLOG -f NGRID $arg
>             rm -f $arg
>        elif [ "XX" !=3D "X`echo $arg | grep BUFtdp`X" ]
>        then=20
>             #echo "NPOINT $arg"
>             cp $arg /comms_dir/oldpsrfiles/$arg
>             pqinsert -l $NPOINTLOG -f NPOINT $arg
>             rm -f $arg
>        elif [ "XX" !=3D "X`echo $arg | grep AWN | grep TXT`X" ]
>        then=20
>             #echo "WMO TXT $arg"
>             cp $arg /comms_dir/oldpsrfiles/$arg
>             pqinsert -l $WMOLOG -f WMO $arg
>             rm -f $arg
>        elif [ "XX" !=3D "X`echo $arg | grep AWN | grep dat`X" ]
>        then=20
>             #echo "WMO DAT $arg"
>             cp $arg /comms_dir/oldpsrfiles/$arg
>             pqinsert -l $WMOLOG -f WMO $arg
>             rm -f $arg
>        else
>             #echo "UNKNOWN $arg"
>             mv $arg /comms_dir/oldpsrfiles/unknowns
>        fi
>       fi
>    done
>    sleep 10
> done

It looks like the above script uses the standard-output stream instead
of the standard-error stream.  You might want to reconsider that
decision and do something like

    echo 1>&2 "$arg is still coming in, will skip over it for now.."

This assumes that the standard-error stream has been redirected
someplace meaningful.  By default, the standard-error stream of an
EXEC-ed process from the LDM configuration-file will be redirected
to "/dev/console" if possible and "/dev/null, otherwise, unless the
user specifies a logfile pathname to the rpc.ldmd program via the "-l"
argument (and the ldmadmin(1) doesn't).

> v/r
> angelo
> 
> Angelo Alvarez
> System Administrator
> NAVPACMETOCCEN/JTWC
> https://www.npmoc.navy.mil
> email: address@hidden
> phone: 808.471.3645
[snip]

Regards,
Steve Emmerson

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