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Datadog

Log metrics for a Service, Route to a local Datadog agent.

Note: The functionality of this plugin as bundled with versions of Kong prior to 0.11.0 differs from what is documented herein. Refer to the CHANGELOG for details.

Terminology

  • plugin: a plugin executing actions inside Kong before or after a request has been proxied to the upstream API.
  • Service: the Kong entity representing an external upstream API or microservice.
  • Route: the Kong entity representing a way to map downstream requests to upstream services.
  • Consumer: the Kong entity representing a developer or machine using the API. When using Kong, a Consumer only communicates with Kong which proxies every call to the said upstream API.
  • Credential: a unique string associated with a Consumer, also referred to as an API key.
  • upstream service: this refers to your own API/service sitting behind Kong, to which client requests are forwarded.

Configuration

Enabling the plugin on a Service

Configure this plugin on a Service by making the following request:

$ curl -X POST http://kong:8001/services/{service}/plugins \
    --data "name=datadog"  \
    --data "config.host=127.0.0.1" \
    --data "config.port=8125"
  • service: the id or name of the Service that this plugin configuration will target.

Enabling the plugin on a Route

Configure this plugin on a Route with:

$ curl -X POST http://kong:8001/routes/{route_id}/plugins \
    --data "name=datadog"  \
    --data "config.host=127.0.0.1" \
    --data "config.port=8125"
  • route_id: the id of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

You can use the http://localhost:8001/plugins endpoint to enable this plugin on specific Consumers:

$ curl -X POST http://kong:8001/plugins \
    --data "name=datadog" \
    --data "consumer_id={consumer_id}"  \
    --data "config.host=127.0.0.1" \
    --data "config.port=8125"

Where consumer_id is the id of the Consumer we want to associate with this plugin.

You can combine consumer_id and service_id

in the same request, to furthermore narrow the scope of the plugin.

Global plugins

All plugins can be configured using the http://kong:8001/plugins/ endpoint. A plugin which is not associated to any Service, Route or Consumer (or API, if you are using an older version of Kong) is considered "global", and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

form parameterdefaultdescription
nameThe name of the plugin to use, in this case datadog
service_idThe id of the Service which this plugin will target.
route_idThe id of the Route which this plugin will target.
enabledtrueWhether this plugin will be applied.
consumer_idThe id of the Consumer which this plugin will target.
config.host
optional

127.0.0.1

The IP address or host name to send data to.
config.port
optional

8125

The port to send data to on the upstream server
config.metrics
optional

All metrics are logged

List of Metrics to be logged. Available values are described at Metrics.
config.prefix
optional

kong

String to be attached as prefix to metric’s name.

Metrics

Plugin currently logs following metrics to the Datadog server about a Service or Route.

Metric description namespace
request_count tracks the request kong.<service_name>.request.count
request_size tracks the request’s body size in bytes kong.<service_name>.request.size
response_size tracks the response’s body size in bytes kong.<service_name>.response.size
latency tracks the time interval between the request started and response received from the upstream server kong.<service_name>.latency
status_count tracks each status code returned as response kong.<service_name>.status.<status>.count and kong.<service_name>.status.<status>.total
unique_users tracks unique users made a request kong.<service_name>.user.uniques
request_per_user tracks request/user kong.<service_name>.user.<consumer_id>.count
upstream_latency tracks the time it took for the final service to process the request kong.<service_name>.upstream_latency
kong_latency tracks the internal Kong latency that it took to run all the plugins kong.<service_name>.kong_latency
status_count_per_user tracks request/status/user kong.<service_name>.user.<customer_id>.status.<status> and kong.<service_name>.user.<customer_id>.status.total

Metric fields

Plugin can be configured with any combination of Metrics, with each entry containing the following fields.

Field description allowed values
name Datadog metric’s name Metrics
stat_type determines what sort of event the metric represents gauge, timer, counter, histogram, meter and set
sample_rate
conditional		 sampling rate number
customer_identifier
conditional		 authenticated user detail consumer_id, custom_id, username
tags
optional		 List of tags key[:value]

Metric requirements

  1. by default all metrics get logged.
  2. metric with stat_type as counter or gauge must have sample_rate defined as well.
  3. unique_users metric only works with stat_type as set.
  4. status_count, status_count_per_user and request_per_user work only with stat_type as counter.
  5. status_count_per_user, request_per_user and unique_users must have customer_identifier defined.

Kong Process Errors

This logging plugin will only log HTTP request and response data. If you are looking for the Kong process error file (which is the nginx error file), then you can find it at the following path: {prefix}/logs/error.log