Experimental Physics and
Industrial Control System

Carlos Pascual <[email protected]> · Mon, 17 Dec 2012 16:43:26 +0100

Thank you all for your replies,

So far I conclude that it is possible to make use of thebeacons to build a 
list of the IPs and ports of the existing IOCs.

But then I can only go from IOCs to Records and/or PVs by modifying the code 
of all the IOCs (or of the launcher scripts of those IOCs). 

This last part is kind of problematic to me since I cannot assume that it will 
be done in all facilities. Note that I am not looking for a solution for my 
facility (we use Tango) but instead we want to provide a library that can be 
used on top of any existing installations elsewhere...

In other words: I don't think I would convince anyone to try out Taurus on 
epics if a requirement was to have to modify all the IOCs... ;)

Are there any chances that something like this may end up being part of a base 
API in epics?

Cheers,

Carlos

On Mon 17 December 2012 15:35:05 Ralph Lange wrote:
> On 17.12.2012 14:52, [email protected] wrote:
> > [...]
> > One or the other, I've not looked to see what would be involved (well, I
> > have now...).  I'd start by thinking of providing a simple socket
> > interface which walks the database, or maybe just returns the results of
> > dbgrep.
> > 
> > Actually, a glance at the implementation of dbgrep (src/db/dbTest.c)
> > suggests that the existing code is close to what you need, but needs a
> > tweak (rather than calling puts you'll want more control over where the
> > strings go), but it looks to me as if all the functions called by dbgrep
> > are exported by epics, so writing what you need should be exceptionally
> > easy: just grab a copy of dbgrep, give it a file handle output, replace
> > puts, wrap a socket interface around it, launch it as part of your IOC
> > startup scripts.
> > 
> > If it were me, I'd dedicate a socket, read one line from the input, treat
> > it as input to the modified dbgrep, send the results in response, close
> > the socket.  Then `echo \* | nc $IOC $PORT` would give you a list of all
> > PVs exported by the IOC.
> > 
> > Of course, you'll need to add this code to every IOC...
> 
> You could also create a device support for the waveform record, that (at
> boot time) creates an array (of char) containing all records' names.
> Then a client can simply use CA to get the complete list from an IOC,
> and there is no runtime overhead on the IOC. (Usually the client will be
> faster at doing wildcard matches anyway.)
> 
> ~Ralph

-- 
+----------------------------------------------------+
 Carlos Pascual Izarra
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System