How to use a Regex return group in Device Studio poller

Question

Hi THWACK community!

I'm trying to create a custom poller (Device Studio type) for this purpose:

https://thwack.solarwinds.com/discussion/41378/no-more-net-snmp-nodes

What I'm currently trying to resolve is to truncate the number off of a Distro name, i.e.: "Red Hat Enterprise Linux 10".

I have a Regular Expression which work outside of SolarWinds:

https://regex101.com/?regex=%28.%29%28%3F%3A%5Cs%5Cd%7B1%2C%7D.%24%29&testString=Red+Hat+Enterprise+Linux+10.2&flags=gm&flavor=pcre2&delimiter=%2F

…but, when I try that in the Custom Poller configuration, there's no result:

If I simplify the Regex to simply return the entire string, I do get the values, so I suspect that it has to do with the capturing groups:

Any suggestions?

mr.castaneda · Answer

What’s biting you here isn’t the capture group itself; it’s the flavor of the regex that Device Studio uses. The Regex() function in Device Studio is much more limited than what regex101 uses:

* It only supports simple patterns (no \d, \s, \w, lookaheads, etc.)
* It interprets input only up to the first \r
* And the docs call out that many “advanced” constructs aren’t supported:
https://documentation.solarwinds.com/en/success_center/orionplatform/content/core-common-formulas-…

That’s why your pattern with (?:\s\d{1,}.*$) works in regex101 but returns nothing in Device Studio.

For your “Red Hat Enterprise Linux 9/10/…” example, you can usually get what you want with a simpler pattern that just matches “everything from the start of the string up to the first non-letter/space”.

For example:

Regex([Vendor],"^[A-Za-z ]+")

That tells Device Studio:

* Start at the beginning of the string
* Match one or more letters or spaces
* Stop as soon as you hit something else (the space + version number), so the version never becomes part of the match

On your test value:

* Input: Red Hat Enterprise Linux 9
* Output: Red Hat Enterprise Linux (you can trim the trailing space visually or with SubString if you really want it gone)

If your vendor strings include other characters (hyphens, parentheses, etc.), you can just add them into the character class.

For example:

Regex([Vendor],"^[A-Za-z ()-]+")