LogStash的CodeC插件实现多行合并

Multiline codec pluginedit

• Plugin version: v3.0.9
• Released on: 2018-01-17
• Changelog

Getting Helpedit

For questions about the plugin, open a topic in the Discuss forums. For bugs or feature requests, open an issue in Github. For the list of Elastic supported plugins, please consult the Elastic Support Matrix.

Descriptionedit

The multiline codec will collapse multiline messages and merge them into a single event.

If you are using a Logstash input plugin that supports multiple hosts, such as the Beats input plugin input plugin, you should not use the multiline codec to handle multiline events. Doing so may result in the mixing of streams and corrupted event data. In this situation, you need to handle multiline events before sending the event data to Logstash.

The original goal of this codec was to allow joining of multiline messages from files into a single event. For example, joining Java exception and stacktrace messages into a single event.

The config looks like this:

input {
  stdin {
    codec => multiline {
      pattern => "pattern, a regexp"
      negate => "true" or "false"
      what => "previous" or "next"
    }
  }
}

The pattern should match what you believe to be an indicator that the field is part of a multi-line event.

The what must be previous or next and indicates the relation to the multi-line event.

The negate can be true or false (defaults to false). If true, a message not matching the pattern will constitute a match of the multiline filter and the what will be applied. (vice-versa is also true)

For example, Java stack traces are multiline and usually have the message starting at the far-left, with each subsequent line indented. Do this:

input {
  stdin {
    codec => multiline {
      pattern => "^\s"
      what => "previous"
    }
  }
}

This says that any line starting with whitespace belongs to the previous line.

Another example is to merge lines not starting with a date up to the previous line..

input {
  file {
    path => "/var/log/someapp.log"
    codec => multiline {
      # Grok pattern names are valid! :)
      pattern => "^%{TIMESTAMP_ISO8601} "
      negate => true
      what => "previous"
    }
  }
}

This says that any line not starting with a timestamp should be merged with the previous line.

One more common example is C line continuations (backslash). Here’s how to do that:

input {
  stdin {
    codec => multiline {
      pattern => "\\$"
      what => "next"
    }
  }
}

This says that any line ending with a backslash should be combined with the following line.