Splunk Search

Multiple capture groups not capturing

arielbintang
New Member

I have the following log structure:

  2023-11-25T21:18:54.244444  [  info      ]  I am a log message  request = GET /api/myendpoint    request_id = ff223452

I can capture the date and time (without the 244444 part) using:

rex field=myfield "(?<timestamp>\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})\.\d+"

and timestamp is properly captured.

But if I try to extend this and want to capture the log level as well with for example:

rex field=myfield "(?<timestamp>\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})\.\d+\s+\[\s*(?<loglevel>\w+)\s*\]\s+"

It didn't work; none of the timestamp nor the loglevel is captured.

What am I doing wrong?

Labels (2)
0 Karma

ITWhisperer
SplunkTrust
SplunkTrust

You don't appear to be doing anything wrong, given the example you have shared.

| makeresults
| eval _raw="2023-11-25T21:18:54.244444  [  info      ]  I am a log message  request = GET /api/myendpoint    request_id = ff223452"
| rex "(?<timestamp>\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})\.\d+\s+\[\s*(?<loglevel>\w+)\s*\]\s+"
0 Karma

arielbintang
New Member

Thanks for verifying! When I copy paste my log directly to the search box from the log message field and used your makeresults, I see that actually some of the spaces are actually  character; do you know why perhaps its not shown in the results itself (and I have to copy paste)?

0 Karma

ITWhisperer
SplunkTrust
SplunkTrust

Assuming that the non-word characters are in the square brackets, you could try something like this

| makeresults
| eval _raw="2023-11-25T21:18:54.244444  [  info      ]  I am a log message  request = GET /api/myendpoint    request_id = ff223452"
| rex "(?<timestamp>\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2})\.\d+\s+\[\W*(?<loglevel>\w+)\W*\]\s+"

but, ideally, you should ask the developers of the application to not use these characters in the first place.

0 Karma
Get Updates on the Splunk Community!

App Platform's 2025 Year in Review: A Year of Innovation, Growth, and Community

As we step into 2026, it’s the perfect moment to reflect on what an extraordinary year 2025 was for the Splunk ...

Operationalizing Entity Risk Score with Enterprise Security 8.3+

Overview Enterprise Security 8.3 introduces a powerful new feature called “Entity Risk Scoring” (ERS) for ...

Unlock Database Monitoring with Splunk Observability Cloud

  In today’s fast-paced digital landscape, even minor database slowdowns can disrupt user experiences and ...