Grok processoredit
Extracts structured fields out of a single text field within a document. You choose which field to extract matched fields from, as well as the grok pattern you expect will match. A grok pattern is like a regular expression that supports aliased expressions that can be reused.
This processor comes packaged with many reusable patterns.
If you need help building patterns to match your logs, you will find the Grok Debugger tool quite useful! The Grok Constructor is also a useful tool.
The Grok Constructor incremental constructor is very helpful.
Lots of online content...