Logstash TCP

input {
  file {
    path => "/var/log/auth.log"
    start_position => "beginning"
    tags => ["auth_log"]
  }

  # A contrived file that contains timing messages
  file {
    path => "/var/log/durations.log"
    tags => ["duration_log"]
    start_position => "beginning"
  }
}

filter {
  if "duration_log" in [tags] {
    dissect {
      mapping => {
        "message" => "Processing took %{duration} seconds"
      }
      convert_datatype => {
        "duration" => "float"
      }
    }
    if "_dissectfailure" not in [tags] { # Filter out bad events
      metrics {
        timer => { "process_time" => "%{duration}" }
        flush_interval => 10
        # This makes the timing stats pertain to only the previous 5 minutes
        # instead of since Logstash last started.
        clear_interval => 300
        add_field => {"type" => "processing"}
        add_tag => "metric"
      }
    }
  }
  # Count the number of logins using SSH from /var/log/auth.log
  if "auth_log" in [tags] and [message] =~ /sshd.*session opened/ {
    metrics {
      # This determines how often metric events will be sent to the agent, and
      # thus how often data points will be emitted.
      flush_interval => 10
      # The name of the meter will be used to construct the name of the metric
      # in Splunk Infrastructure Monitoring. For this example, a data point called `logins.count` would
      # be generated.
      meter => "logins"
      add_tag => "metric"
    }
  }
}

output {
  # This can be helpful to debug
  stdout { codec => rubydebug }

  if "metric" in [tags] {
    tcp {
      port => 8900
      # The agent will connect to Logstash
      mode => "server"
      # Needs to be "0.0.0.0" if running in a container.
      host => "127.0.0.1"
    }
  }
}