gistfile1.txt

/tmp/logstash-7.10.1
❯ cat cfg
input {
  generator {
    codec => json
    message => '{"systat": {"start": {"timestamp": {"timesecs": 10}}, "intervals": {"streams": {"end": 10}}}}'
    count => 1
  }
}
filter {
 ruby {
    code => 'event.set("[systat][start][timestamp][timesecsunix]", [ event.get("[systat][start][timestamp][timesecs]")+ event.get("[systat][intervals][streams][end]") ] )'
  }
}
output {stdout {} }

/tmp/logstash-7.10.1
❯ bin/logstash -f cfg
Using JAVA_HOME defined java: /Users/joaoduarte/.jenv/versions/1.8
WARNING, using JAVA_HOME while Logstash distribution comes with a bundled JDK
Sending Logstash logs to /tmp/logstash-7.10.1/logs which is now configured via log4j2.properties
[2021-01-15T11:13:50,852][INFO ][logstash.runner          ] Starting Logstash {"logstash.version"=>"7.10.1", "jruby.version"=>"jruby 9.2.13.0 (2.5.7) 2020-08-03 9a89c94bcc OpenJDK 64-Bit Server VM 25.232-b09 on 1.8.0_232-b09 +indy +jit [darwin-x86_64]"}
[2021-01-15T11:13:51,059][WARN ][logstash.config.source.multilocal] Ignoring the 'pipelines.yml' file because modules or command line options are specified
[2021-01-15T11:13:52,504][INFO ][org.reflections.Reflections] Reflections took 32 ms to scan 1 urls, producing 23 keys and 47 values 
[2021-01-15T11:13:53,825][INFO ][logstash.javapipeline    ][main] Starting pipeline {:pipeline_id=>"main", "pipeline.workers"=>8, "pipeline.batch.size"=>125, "pipeline.batch.delay"=>50, "pipeline.max_inflight"=>1000, "pipeline.sources"=>["/private/tmp/logstash-7.10.1/cfg"], :thread=>"#<Thread:0xcbcb885 run>"}
[2021-01-15T11:13:54,487][INFO ][logstash.javapipeline    ][main] Pipeline Java execution initialization time {"seconds"=>0.65}
[2021-01-15T11:13:54,512][INFO ][logstash.javapipeline    ][main] Pipeline started {"pipeline.id"=>"main"}
[2021-01-15T11:13:54,573][INFO ][logstash.agent           ] Pipelines running {:count=>1, :running_pipelines=>[:main], :non_running_pipelines=>[]}
[2021-01-15T11:13:54,983][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>9600}
{
        "systat" => {
            "start" => {
            "timestamp" => {
                    "timesecs" => 10,
                "timesecsunix" => [
                    [0] 20
                ]
            }
        },
        "intervals" => {
            "streams" => {
                "end" => 10
            }
        }
    },
      "sequence" => 0,
      "@version" => "1",
    "@timestamp" => 2021-01-15T11:13:54.620Z,
          "host" => "joaos-mbp.lan"
}
[2021-01-15T11:13:55,193][INFO ][logstash.javapipeline    ][main] Pipeline terminated {"pipeline.id"=>"main"}
[2021-01-15T11:13:55,665][INFO ][logstash.pipelinesregistry] Removed pipeline from registry successfully {:pipeline_id=>:main}
[2021-01-15T11:13:55,711][INFO ][logstash.runner          ] Logstash shut down.