Splunk Search

Don't get eval based macros

andersmholmgren
Explorer

I just can't seem to understand how the eval based macros are supposed to work

I wrote a very simple macro

[TEST]
definition = "TEST"
iseval = 1

then a query to test the output

index=_audit | head 1 | eval test1=`TEST`  | eval test2=tostring(`TEST`) | table test*

The output is one column 'test2' with a value of Null

Why is that? Shouldn't the value be "TEST" for both columns? If not why not?

Tags (3)
0 Karma
1 Solution

genthaler
Engager

Try this:

[TEST]
definition = "\"TEST\""
iseval = 1

View solution in original post

gkanapathy
Splunk Employee
Splunk Employee

An eval-based macro returns a string, which is substituted into the query. Your macro returns the string TEST, without quotes, so you are getting:

... | eval test1=TEST  | eval test2=tostring(TEST) | ...

In this case, TEST is used as the name of a non-existent variable. You can get what you intended either with @genthaler's answer, or by putting the quotes in the query:

... | eval test1="`TEST`"  | eval test2=tostring("`TEST`") | ...

genthaler
Engager

Hi @gkanapathy,
I just tried it, unfortunately quoted macro invocations don't get invoked.
So instead of "TEST", you end up with the literal string "`TEST`".

0 Karma

genthaler
Engager

Try this:

[TEST]
definition = "\"TEST\""
iseval = 1

Get Updates on the Splunk Community!

Introducing Splunk Enterprise 9.2

WATCH HERE! Watch this Tech Talk to learn about the latest features and enhancements shipped in the new Splunk ...

Adoption of RUM and APM at Splunk

    Unleash the power of Splunk Observability   Watch Now In this can't miss Tech Talk! The Splunk Growth ...

Routing logs with Splunk OTel Collector for Kubernetes

The Splunk Distribution of the OpenTelemetry (OTel) Collector is a product that provides a way to ingest ...