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[LDM #RMC-391545]: Variable names in pqact output file path?



Neil,

> Is there a syntax available to reference a variableâs content somewhere in 
> the output path name specification in a pqact entry?
> 
> Iâm wanting to investigate a way of removing a previous version of a 
> product file when the latest version has arrived.
> 
> For example, say a NEXRCOMP pqact entry looks like
> 
> FNEXRAD ^rad/NEXRCOMP/(...)/(...)_(........)_(....)
> FILE    -close  data/gempak/nexrad/NEXRCOMP/\1/\2/\2_\3_\4
> 
> and with product output file path
> 
> /data/gempak/nexrad/NEXRCOMP/1km/n0r/n0r_20151026_0615
> 
> When considering a particular use of the linux âdateâ command that looks 
> like
> 
> > date -d '20151029 -3 days' +%Y%m%d
> 20151026
> 
> it is very tempting to consider something like
> 
> FNEXRAD       ^rad/NEXRCOMP/(...)/(...)_(........)_(....)
> FILE    -close  data/gempak/nexrad/NEXRCOMP/\1/\2/\2_\3_\4
> 
> FNEXRAD       ^rad/NEXRCOMP/(...)/(...)_(........)_(....)
> EXEC    set plugin = `/bin/date  -d '\3 -3 dayâ`
> 
> FNEXRAD       ^rad/NEXRCOMP/(...)/(...)_(........)_(....)
> EXEC    /bin/rm -f data/gempak/nexrad/NEXRCOMP/\1/\2/test_\2_${plugin}_\4
> 
> to âscourâ in real time the on-disk population of an ingested IDD product 
> by removing
> 
> /data/gempak/nexrad/NEXRCOMP/1km/n0r/n0r_20151026_0615
> 
> (I assume that the ldm will not except more than one pattern action per 
> pattern)
> 
> Is this a bit hair-balled?
> 
> -Neil

You idea isn't "hair-balled", as you say. It might not be what you want, 
however. Modifying the parsing of the pqact(1) configuration-file is 
straightforward but non-trivial; consequently, it would take time (which is in 
short supply). Additionally, the result might not perform as well as you'd like 
because a separate process would be created, executed, and terminated for every 
arriving data-product that matched the pattern. This would result in deletion 
that would be no better than using the command "find ... -exec rm {}", which is 
already too slow in some circumstances.

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: RMC-391545
Department: Support LDM
Priority: Normal
Status: Closed


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