Re: EPICS CA Gateway Aliases

["Johnson, Andrew N. via Tech-talk" <tech-talk at aps.anl.gov>]

Hi William,

 

The ALIAS syntax requires you to specify the alias name using back-references \1 \2 etc. The exact pattern syntax depends on which regex engine you’re using. Our gateways are built using the GNU regex library, here are some examples from one of our pvList files:

 

^Mt:S:NumBucketsFilledAI\(.*\)  ALIAS   XFD:NumFilledBuckets\1

^Mt:S:FilledBucketsWF\(.*\)     ALIAS   S-INJ:ActiveBucketFillQueueArrayM\1

^Mt:S:FillPatternWF\(.*\)       ALIAS   XFD:FilledBuckets\1

^S:BeamStatusMBBI\(.*\)         ALIAS   XFD:BeamStatus\1

^S:InjectingStatusMBBI\(.*\)    ALIAS   XFD:InjectingStatus\1

 

If you’re using PCRE you won’t use back-slashes before the capturing parentheses on the left, but your back-references on the right side should be the same. Our configuration doesn’t specify an asg or asl for these PV names, you’ll add those as necessary.

 

HTH,

 

- Andrew

 

-- 

Complexity comes for free, Simplicity you have to work for.

 

 

On 1/13/25, 11:06 AM, "Tech-talk" <tech-talk-bounces at aps.anl.gov> wrote:

 

We are attempting to update the PV naming scheme at our lab. Part of our plan is to use aliases in the EPICS CA Gateway to allow for clients in other networks to access PV's with old PV names for a while. 

Is it possible to define regular _expression_ mappings for the aliases, or do I have to define exact mapping from one PV to another?

So far I have not had much luck with for example:

SISSY2EX:.*    ALIAS SISSY2ES12X:.* BLC_EMIL

 

where "SISSY2EX:" is an old prefix and "SISSY2ES12X:" is a new prefix.