Datadog - Plugin - unreleased

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Looking for the plugin's configuration parameters? You can find them in the Datadog configuration reference doc.

Log metrics for a service or route to a local Datadog agent.

Queueing

The Datadog uses a queue to decouple the production and consumption of data. This reduces the number of concurrent requests made to the upstream server under high load situations and provides buffering during temporary network or upstream outages.

You can set several parameters to configure the behavior and capacity of the queues used by the plugin. For more information about how to use these parameters, see Plugin Queuing Reference in the Kong Gateway documentation.

The queue parameters all reside in a record under the key queue in the config parameter section of the plugin.

Queues are not shared between workers and queueing parameters are scoped to one worker. For whole-system capacity planning, the number of workers need to be considered when setting queue parameters.

Metrics

The Datadog plugin currently logs the following metrics to the Datadog server about a service or route.

Metric	Description	Namespace
`request_count`	tracks the request	`kong.request.count`
`request_size`	tracks the request’s body size in bytes	`kong.request.size`
`response_size`	tracks the response’s body size in bytes	`kong.response.size`
`latency`	tracks the time interval between the request started and response received from the upstream server	`kong.latency`
`upstream_latency`	tracks the time it took for the final service to process the request	`kong.upstream_latency`
`kong_latency`	tracks the internal Kong latency that it took to run all the plugins	`kong.kong_latency`

The metrics will be sent with the tags name and status carrying the API name and HTTP status code respectively. If you specify consumer_identifier with the metric, a tag consumer will be added.

Metric fields

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

Field	Description	Data types	Allowed values
`name`	Datadog metric’s name	String	Metrics
`stat_type`	Determines what sort of event the metric represents	String	`gauge`, `timer`, `counter`, `histogram`, `meter`, `set` , `distribution`
`sample_rate` conditional	Sampling rate	Number	`number`
`consumer_identifier` conditional	Authenticated user detail	String	`consumer_id`, `custom_id`, `username`
`tags` optional	List of tags	Array of strings	`key[:value]`

Metric requirements

All metrics get logged by default.
Metrics with stat_type as counter or gauge must have sample_rate defined as well.

Migrating Datadog queries

The plugin updates replace the api, status, and consumer-specific metrics with a generic metric name. You must change your Datadog queries in dashboards and alerts to reflect the metrics updates.

For example, the following query:

avg:kong.sample_service.latency.avg{*}

would need to change to:

avg:kong.latency.avg{name:sample-service}

Setting host and port per Kong node basis

When installing a multi-data center setup, you might want to set Datadog’s agent host and port on a per Kong node basis. This configuration is possible by setting the host and port properties using environment variables.

Note: host and port fields in the plugin config take precedence over environment variables.

For Kubernetes, there is a known limitation that you can’t set host to null to use the environment variable. You can work around this by using a vault reference, for example: {vault://env/kong-datadog-agent-host}. Refer to Configure with Kubernetes.

Field	Description	Data types
`KONG_DATADOG_AGENT_HOST`	The IP address or hostname to send data to.	string
`KONG_DATADOG_AGENT_PORT`	The port to send data to on the upstream server.	integer

Kong process errors

This logging plugin logs HTTP request and response data, and also supports stream data (TCP, TLS, and UDP).

The Kong process error file is the Nginx error file. You can find it at the following path:

{prefix}/logs/error.log

Configure the prefix in kong.conf.

Configure with Kubernetes

In most Kubernetes setups, datadog-agent runs as a daemon set. This means that a datadog-agent runs on each node in the Kubernetes cluster, and Kong Gateway must forward metrics to the datadog-agent running on the same node as Kong Gateway.

This can be accomplished by providing the IP address of the Kubernetes worker node to Kong Gateway, then configuring the plugin to use that IP address. This is achieved using environment variables.

Helm

Kubernetes YAML

Modify the env section in values.yaml:

 env:
   datadog_agent_host:
     valueFrom:
       fieldRef:
         fieldPath: status.hostIP

Update the Helm deployment:

 helm upgrade -f values.yaml RELEASE_NAME kong/kong --version VERSION --namespace NAMESPACE

Modify the plugin’s configuration:

 apiVersion: configuration.konghq.com/v1
 kind: KongClusterPlugin
 metadata:
   name: datadog
   annotations:
     kubernetes.io/ingress.class: kong
   labels:
     global: "true"
 config:
   host: "{vault://env/kong-datadog-agent-host}"
   port: 8125

Modify the env section in values.yaml:

 env:
   - name: KONG_DATADOG_AGENT_HOST
     valueFrom:
       fieldRef:
         fieldPath: status.hostIP

Modify the plugin’s configuration:

 apiVersion: configuration.konghq.com/v1
 kind: KongClusterPlugin
 metadata:
   name: datadog
   annotations:
     kubernetes.io/ingress.class: kong
   labels:
     global: "true"
 config:
   host: "{vault://env/kong-datadog-agent-host}"
   port: 8125

Next Datadog Configuration