docs-v2/content/kapacitor/v1/reference/event_handlers/tcp.md

title	list_title	description	menu	aliases
TCP event handler	TCP	The "tcp" event handler allows you to send Kapacitor alert data to a TCP endpoint. This page includes options and usage examples.	kapacitor_v1 name weight parent TCP 1900 Event handlers	/kapacitor/v1/event_handlers/tcp/

The TCP event handler sends JSON encoded alert data to a TCP endpoint.

Options

The following TCP event handler options can be set in a handler file or when using .tcp() in a TICKscript.

Name	Type	Description
address	string	Address of TCP endpoint.

Example: handler file

id: handler-id
topic: topic-name
kind: tcp
options:
  address: 127.0.0.1:7777

Example: TICKscript

|alert()
  // ...
  .tcp('127.0.0.1:7777')

Using the TCP event handler

The TCP event handler can be used in both TICKscripts and handler files to send alert data to TCP endpoint.

Send alert data to a TCP endpoint from a TICKscript

The following TICKscript uses the .tcp() event handler to send alert data whenever idle CPU usage drops below 10%.

tcp-cpu-alert.tick

stream
  |from()
    .measurement('cpu')
  |alert()
    .crit(lambda: "usage_idle" < 10)
    .message('Hey, check your CPU')
    .tcp('127.0.0.1:7777')

Send alert data to a TCP endpoint from a defined handler

The following setup sends an alert to the cpu topic with the message, "Hey, check your CPU". A TCP handler is added that subscribes to the cpu topic and sends all alert messages to a TCP endpoint.

Create a TICKscript that publishes alert messages to a topic. The TICKscript below sends an alert message to the cpu topic any time idle CPU usage drops below 10%.

cpu_alert.tick

stream
  |from()
    .measurement('cpu')
  |alert()
    .crit(lambda: "usage_idle" < 10)
    .message('Hey, check your CPU')
    .topic('cpu')

Add and enable the TICKscript:

kapacitor define cpu_alert -tick cpu_alert.tick
kapacitor enable cpu_alert

Create a handler file that subscribes to the cpu topic and uses the TCP event handler to send alert data to a TCP endpoint.

tcp_cpu_handler.yaml

id: tcp-cpu-alert
topic: cpu
kind: tcp
options:
  address: 127.0.0.1:7777

Add the handler:

kapacitor define-topic-handler tcp_cpu_handler.yaml