Logstash grok filter for parsing nested data?

Elastic Stack Logstash
1

I have log messages with field data delimited by [ ] characters. The problem is that sometimes the data in the field contains those characters. How do I write the grok pattern to take the nesting level into account, excluding the outer brackets?

Example, given the field data:

[aaa[bbb]ccc[ddd[14]]]

I want to parse it such that the resulting field contains

aaa[bbb]ccc[ddd[14]]

Thanks

2

I would say that you would need to use some regex to get this done, the following would match everything between the first and last square brackets:

(?<YourResult>(?<=\[).*?(?=\]$))

You can change the 'YourResult' text to name the captured results

3

Thanks! What I forgot to mention is that there is another field following this one that I don't want to match. I want that to be matched separately. So, a better example would be:

... [aaa[bbb]ccc[ddd[14]]][name=zyz]

Your suggestion seems to be in the right direction but I think it will match too much in this case. I'm still working on it.

4

I would suggest having a look at this site: http://grokconstructor.appspot.com/do/construction

It will allow you to build the grok query and capture the data you need.

Tim