Dissect filter is an alternative to Grok filter and can be used to extract structured fields from an unstructured line. However, if the structure of your text varies from line to line then Grok is more suitable. There is a hybrid case where Dissect can be used to de-structure the section of the line that is reliably repeated and then Grok can be used on the remaining field values with more regex predictability and less overall work to do.

A set of fields and delimiters is called a dissection.

The dissection is described using a set of %{} sections: .... %{a} - %{b} - %{c} ....

A field is the text from % to } inclusive.

A delimiter is the text between } and % characters. Delimiters can't contain these }{% characters.

The config might look like this:

 filter {
   dissect {
     mapping => {
       "message" => "%{ts} %{+ts} %{+ts} %{src} %{} %{prog}[%{pid}]: %{msg}"


Please read

Logstash Plugin

Travis Build Status

This is a plugin for Logstash.

It is fully free and fully open source. The license is Apache 2.0, meaning you are pretty much free to use it however you want in whatever way.


Logstash provides infrastructure to automatically generate documentation for this plugin. We use the asciidoc format to write documentation so any comments in the source code will be first converted into asciidoc and then into html. All plugin documentation are placed under one central location.

Need Help?

Need help? Try #logstash on freenode IRC or the discussion forum.


1. Plugin Developement and Testing



bundle install
bundle exec rspec

2. Running your unpublished Plugin in Logstash

2.1 Run in a local Logstash clone

Prior to Logstash 2.3

bin/plugin install --no-verify

- Run Logstash with your plugin
bin/logstash -e 'filter {awesome {}}'

At this point any modifications to the plugin code will be applied to this local Logstash setup. After modifying the plugin, simply rerun Logstash.

2.2 Run in an installed Logstash

You can use the same 2.1 method to run your plugin in an installed Logstash by editing its Gemfile and pointing the :path to your local plugin development directory or you can build the gem and install it using:

Prior to Logstash 2.3

bin/plugin install --no-verify

- Start Logstash and proceed to test the plugin

## Contributing

All contributions are welcome: ideas, patches, documentation, bug reports, complaints, and even something you drew up on a napkin.

Programming is not a required skill. Whatever you've seen about open source and maintainers or community members  saying "send patches or die" - you will not see that here.

It is more important to the community that you are able to contribute.

For more information about contributing, see the [CONTRIBUTING]( file.