Elastic LogStash


User Defined Function (Filter plugin) for Elastic Logstash


The logstash UDF java api is still experimental.

See for more information:

Getting the UDF

You can get the prebuilt filter from the GitHub releases page.

Building has side effects !

Because at this time none of the required dependencies are in maven central this build does something rarely seen:

It downloads the entire logstash distribution, extracts the logstash-core.jar and installs it locally for maven to use as dependency.

So your local maven repo will get a jar injected that is not normally available via Maven central or something similar.

See these for more details:

Installing the filter

You only need to install it into your logstash once per installation

logstash-plugin remove logstash-filter-yauaa
logstash-plugin install ./udfs/logstash/target/logstash-filter-yauaa-7.17.0.gem

Example usage

You need to specify

  1. The source field which maps the fields in the record to their original request headers.
  2. For each Yauaa field you need the logstash field in which it needs to be placed.
filter {
  yauaa {
    source => {
      "ua"      => "User-Agent"
      "uap"     => "Sec-CH-UA-Platform"
      "uapv"    => "Sec-CH-UA-Platform-Version"
    fields => {
      "DeviceClass"                      => "uaDC"
      "DeviceName"                       => "uaDN"
      "DeviceBrand"                      => "uaDB"
      "OperatingSystemClass"             => "uaOSC"
      "OperatingSystemNameVersion"       => "uaOSNV"
      "LayoutEngineClass"                => "uaLEC"
      "LayoutEngineNameVersion"          => "uaLENV"
      "AgentClass"                       => "uaAC"
      "AgentName"                        => "uaAN"
      "AgentNameVersion"                 => "uaAANV"
      "AgentNameVersionMajor"            => "uaANVM"

When running this example I get output like this (sorted the fields for readbility) that has the new fields:

    "@timestamp" => 2022-04-24T09:30:11.051Z,
      "@version" => "1",
          "host" => "b9bf088b8c92",
       "message" => "HeartBeat event to trigger the test",
            "ua" => "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.60 Safari/537.36",
           "uap" => "\"macOS\"",
          "uapv" => "\"12.3.1\"",
          "uaDC" => "Desktop",
          "uaDN" => "Apple Macintosh",
          "uaDB" => "Apple",
         "uaOSC" => "Desktop",
        "uaOSNV" => "Mac OS 12.3.1",
         "uaLEC" => "Browser",
        "uaLENV" => "Blink 100.0",
          "uaAC" => "Browser",
          "uaAN" => "Chrome",
        "uaANVM" => "Chrome 100",
        "uaAANV" => "Chrome 100.0.4896.60"