elapsed

edit

This is a community-maintained plugin! It does not ship with Logstash by default, but it is easy to install by running bin/logstash-plugin install logstash-filter-elapsed.

This filter tracks a pair of start/end events and calculates the elapsed time between them. The elapsed filter tracks a pair of start/end events and uses their timestamps to calculate the elapsed time between them.

The filter has been developed to track the execution time of processes and other long tasks.

The configuration looks like this:

    filter {
      elapsed {
        start_tag => "start event tag"
        end_tag => "end event tag"
        unique_id_field => "id field name"
        timeout => seconds
        new_event_on_match => true/false
      }
    }

The events managed by this filter must have some particular properties. The event describing the start of the task (the "start event") must contain a tag equal to start_tag. On the other side, the event describing the end of the task (the "end event") must contain a tag equal to end_tag. Both these two kinds of event need to own an ID field which identify uniquely that particular task. The name of this field is stored in unique_id_field.

You can use a Grok filter to prepare the events for the elapsed filter. An example of configuration can be:

    filter {
      grok {
        match => ["message", "%{TIMESTAMP_ISO8601} START id: (?<task_id>.*)"]
        add_tag => [ "taskStarted" ]
      }

      grok {
        match => ["message", "%{TIMESTAMP_ISO8601} END id: (?<task_id>.*)"]
        add_tag => [ "taskTerminated"]
      }

      elapsed {
        start_tag => "taskStarted"
        end_tag => "taskTerminated"
        unique_id_field => "task_id"
      }
    }

The elapsed filter collects all the "start events". If two, or more, "start events" have the same ID, only the first one is recorded, the others are discarded.

When an "end event" matching a previously collected "start event" is received, there is a match. The configuration property new_event_on_match tells where to insert the elapsed information: they can be added to the "end event" or a new "match event" can be created. Both events store the following information:

  • the tags elapsed and elapsed.match
  • the field elapsed.time with the difference, in seconds, between the two events timestamps
  • an ID filed with the task ID
  • the field elapsed.timestamp_start with the timestamp of the start event

If the "end event" does not arrive before "timeout" seconds, the "start event" is discarded and an "expired event" is generated. This event contains:

  • the tags elapsed and elapsed.expired_error
  • a field called elapsed.time with the age, in seconds, of the "start event"
  • an ID filed with the task ID
  • the field elapsed.timestamp_start with the timestamp of the "start event"

 

Synopsis

edit

This plugin supports the following configuration options:

Required configuration options:

elapsed {
    end_tag => ...
    start_tag => ...
    unique_id_field => ...
}

Available configuration options:

Setting Input type Required Default value

add_field

hash

No

{}

add_tag

array

No

[]

end_tag

string

Yes

new_event_on_match

boolean

No

false

periodic_flush

boolean

No

false

remove_field

array

No

[]

remove_tag

array

No

[]

start_tag

string

Yes

timeout

number

No

1800

unique_id_field

string

Yes

Details

edit

 

add_field

edit
  • Value type is hash
  • Default value is {}

If this filter is successful, add any arbitrary fields to this event. Field names can be dynamic and include parts of the event using the %{field}.

Example:

    filter {
      elapsed {
        add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
      }
    }
    # You can also add multiple fields at once:
    filter {
      elapsed {
        add_field => {
          "foo_%{somefield}" => "Hello world, from %{host}"
          "new_field" => "new_static_value"
        }
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would add field foo_hello if it is present, with the value above and the %{host} piece replaced with that value from the event. The second example would also add a hardcoded field.

add_tag

edit
  • Value type is array
  • Default value is []

If this filter is successful, add arbitrary tags to the event. Tags can be dynamic and include parts of the event using the %{field} syntax.

Example:

    filter {
      elapsed {
        add_tag => [ "foo_%{somefield}" ]
      }
    }
    # You can also add multiple tags at once:
    filter {
      elapsed {
        add_tag => [ "foo_%{somefield}", "taggedy_tag"]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would add a tag foo_hello (and the second example would of course add a taggedy_tag tag).

end_tag

edit
  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

The name of the tag identifying the "end event"

new_event_on_match

edit
  • Value type is boolean
  • Default value is false

This property manage what to do when an "end event" matches a "start event". If it’s set to false (default value), the elapsed information are added to the "end event"; if it’s set to true a new "match event" is created.

periodic_flush

edit
  • Value type is boolean
  • Default value is false

Call the filter flush method at regular interval. Optional.

remove_field

edit
  • Value type is array
  • Default value is []

If this filter is successful, remove arbitrary fields from this event. Fields names can be dynamic and include parts of the event using the %{field}

Example:

    filter {
      elapsed {
        remove_field => [ "foo_%{somefield}" ]
      }
    }
    # You can also remove multiple fields at once:
    filter {
      elapsed {
        remove_field => [ "foo_%{somefield}", "my_extraneous_field" ]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would remove the field with name foo_hello if it is present. The second example would remove an additional, non-dynamic field.

remove_tag

edit
  • Value type is array
  • Default value is []

If this filter is successful, remove arbitrary tags from the event. Tags can be dynamic and include parts of the event using the %{field} syntax.

Example:

    filter {
      elapsed {
        remove_tag => [ "foo_%{somefield}" ]
      }
    }
    # You can also remove multiple tags at once:
    filter {
      elapsed {
        remove_tag => [ "foo_%{somefield}", "sad_unwanted_tag"]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would remove the tag foo_hello if it is present. The second example would remove a sad, unwanted tag as well.

start_tag

edit
  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

The name of the tag identifying the "start event"

timeout

edit
  • Value type is number
  • Default value is 1800

The amount of seconds after an "end event" can be considered lost. The corresponding "start event" is discarded and an "expired event" is generated. The default value is 30 minutes (1800 seconds).

unique_id_field

edit
  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

The name of the field containing the task ID. This value must uniquely identify the task in the system, otherwise it’s impossible to match the couple of events.