topic Re: Create tag for rex field in Splunk Search

Create tag for rex field

bablucho — Tue, 12 Oct 2021 11:36:08 GMT

Hey All,

I get no results found for a tag that looks for fields created by a rex.

So...

sourcetype=DataServices | rex "JOB: Job (?<BIMEJob><(?<=<).*(?=>)>)"

i get the following field with results

Now i want to bunch some field values together so i create a tag containing the field values i care about

added to my search but i get no results found...

sourcetype=DataServices tag=GB1_BIME | rex "JOB: Job (?<BIMEJob><(?<=<).*(?=>)>)"

Greatly appreciated if someone could help?

Re: Create tag for rex field

richgalloway — Tue, 12 Oct 2021 12:54:14 GMT

The tag expects the BIMEJob field to have two values at the same time, which is not possible.

Re: Create tag for rex field

bablucho — Tue, 12 Oct 2021 14:21:51 GMT

the BIMEJob field returns multiple values but i want only 2 values as defined in the tag.

Apologies i do not understand why it would not return results for the tag as the BIMEJob field does contain the values in the tag, just doesnt show it in the search

Re: Create tag for rex field

richgalloway — Tue, 12 Oct 2021 15:17:05 GMT

I'm wondering if the angle brackets are interfering with things. Try putting quotation marks around the right-hand side of each tag pair.

BIMEJob="<ds.scheduler.job>"

Re: Create tag for rex field

bowesmana — Tue, 12 Oct 2021 21:34:10 GMT

I didn't think you could have tags created during the search based on statements that occur in search. There is a defined order of search time operations, where tags are created last

https://docs.splunk.com/Documentation/Splunk/8.2.2/Knowledge/Searchtimeoperationssequence

but if you start doing rex statements during your query, I don't think Splunk will then recalculate tags again based on new fields you have created.

If you want to create tags, then create the BIMEJob field as a field extraction, so it will be available before the tags are created. However, I suspect @richgalloway answer that the two definitions not being supported will still hold true.

You could however, create an eventtype where you have the two conditions BIMEJob=A OR BIMEJob=B and then assign the tag to the eventtype, but this would again have to be done pre search.

Re: Create tag for rex field

bablucho — Tue, 19 Oct 2021 13:32:40 GMT

@bowesmana thanks for your input.

I've tried other suggestions i.e placing quotation marks, removing <> but no die.

it seems you are right by documentation that it is not possible due to tags created last during search time operation order.

i will instead use linebreaking to break the events correctly, this way the fields i care about will be created automatically at index time.