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Correlation ID

Correlate requests and responses using a unique ID transmitted over an HTTP header.

Configuration Reference

You can configure this plugin using the Kong Admin API or through declarative configuration, which involves directly editing the Kong configuration file.

This plugin is compatible with requests with the following protocols:

  • http
  • https

This plugin is compatible with DB-less mode.

In DB-less mode, Kong does not have an Admin API. If using this mode, configure the plugin using declarative configuration.

Enabling the plugin on a Service

Kong Admin API
Kubernetes
Declarative (YAML)

For example, configure this plugin on a Service by making the following request:

$ curl -X POST http://<admin-hostname>:8001/services/<service>/plugins \
    --data "name=correlation-id"  \
    --data "config.header_name=Kong-Request-ID" \
    --data "config.generator=uuid#counter" \
    --data "config.echo_downstream=false"

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: <correlation-id-example>
config: 
  header_name: Kong-Request-ID
  generator: uuid#counter
  echo_downstream: false
plugin: correlation-id

Next, apply the KongPlugin resource to a Service by annotating the Service as follows:

apiVersion: v1
kind: Service
metadata:
  name: <service>
  labels:
    app: <service>
  annotations:
    konghq.com/plugins: <correlation-id-example>
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: <service>
  selector:
    app: <service>
Note: The KongPlugin resource only needs to be defined once and can be applied to any Service, Consumer, or Route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

For example, configure this plugin on a Service by adding this section to your declarative configuration file:

plugins:
- name: correlation-id
  service: <service>
  config: 
    header_name: Kong-Request-ID
    generator: uuid#counter
    echo_downstream: false

<service> is the id or name of the Service that this plugin configuration will target.

Enabling the plugin on a Route

Kong Admin API
Kubernetes
Declarative (YAML)

For example, configure this plugin on a Route with:

$ curl -X POST http://<admin-hostname>:8001/routes/<route>/plugins \
    --data "name=correlation-id"  \
    --data "config.header_name=Kong-Request-ID" \
    --data "config.generator=uuid#counter" \
    --data "config.echo_downstream=false"

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: <correlation-id-example>
config: 
  header_name: Kong-Request-ID
  generator: uuid#counter
  echo_downstream: false
plugin: correlation-id

Then, apply it to an ingress (Route or Routes) by annotating the ingress as follows:

apiVersion: networking/v1beta1
kind: Ingress
metadata:
  name: <route>
  annotations:
    kubernetes.io/ingress.class: kong
    konghq.com/plugins: <correlation-id-example>
spec:
  rules:
  - host: examplehostname.com
    http:
      paths:
      - path: /bar
        backend:
          serviceName: echo
          servicePort: 80
Note: The KongPlugin resource only needs to be defined once and can be applied to any Service, Consumer, or Route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

For example, configure this plugin on a Route by adding this section to your declarative configuration file:

plugins:
- name: correlation-id
  route: <route>
  config: 
    header_name: Kong-Request-ID
    generator: uuid#counter
    echo_downstream: false

<route> is the id or name of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

Kong Admin API
Kubernetes
Declarative (YAML)

For example, configure this plugin on a Consumer with:

$ curl -X POST http://<admin-hostname>:8001/consumers/<consumer>/plugins \
    --data "name=correlation-id"  \
    --data "config.header_name=Kong-Request-ID" \
    --data "config.generator=uuid#counter" \
    --data "config.echo_downstream=false"

You can combine consumer.id, service.id, or route.id in the same request, to further narrow the scope of the plugin.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: <correlation-id-example>
config: 
  header_name: Kong-Request-ID
  generator: uuid#counter
  echo_downstream: false
plugin: correlation-id

Then, apply it to a Consumer by annotating the KongConsumer resource as follows:

apiVersion: configuration.konghq.com/v1
kind: KongConsumer
metadata:
  name: <consumer>
  annotations:
    konghq.com/plugins: <correlation-id-example>
    kubernetes.io/ingress.class: kong
Note: The KongPlugin resource only needs to be defined once and can be applied to any Service, Consumer, or Route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

For example, configure this plugin on a Consumer by adding this section to your declarative configuration file:

plugins:
- name: correlation-id
  consumer: <consumer>
  config: 
    header_name: Kong-Request-ID
    generator: uuid#counter
    echo_downstream: false

<consumer> is the id or username of the Consumer that this plugin configuration will target.

Enabling the plugin globally

A plugin which is not associated to any Service, Route, or Consumer is considered global, and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

Kong Admin API
Kubernetes
Declarative (YAML)

For example, configure this plugin globally with:

$ curl -X POST http://<admin-hostname>:8001/plugins/ \
    --data "name=correlation-id"  \
    --data "config.header_name=Kong-Request-ID" \
    --data "config.generator=uuid#counter" \
    --data "config.echo_downstream=false"

Create a KongClusterPlugin resource and label it as global:

apiVersion: configuration.konghq.com/v1
kind: KongClusterPlugin
metadata:
  name: <global-correlation-id>
  annotations:
    kubernetes.io/ingress.class: kong
  labels:
    global: \"true\"
config: 
  header_name: Kong-Request-ID
  generator: uuid#counter
  echo_downstream: false
plugin: correlation-id

For example, configure this plugin using the plugins: entry in the declarative configuration file:

plugins:
- name: correlation-id
  config: 
    header_name: Kong-Request-ID
    generator: uuid#counter
    echo_downstream: false

Parameters

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

Form ParameterDescription
name

Type: string		 The name of the plugin to use, in this case correlation-id.
service.id

Type: string		 The ID of the Service the plugin targets.
route.id

Type: string		 The ID of the Route the plugin targets.
consumer.id

Type: string		 The ID of the Consumer the plugin targets.
enabled

Type: boolean

Default value: true		 Whether this plugin will be applied.
config.header_name
optional

Default value: Kong-Request-ID

The HTTP header name to use for the correlation ID.
config.generator
optional

Default value: uuid#counter

The generator to use for the correlation ID. Accepted values are uuid, uuid#counter and tracker See Generators.
config.echo_downstream
optional

Default value: false

Whether to echo the header back to downstream (the client).

How it works

When enabled, this plugin will add a new header to all of the requests processed by Kong. This header bears the name configured in config.header_name, and a unique value generated according to config.generator.

This header is always added to calls to your upstream services, and optionally echoed back to your clients according to the config.echo_downstream setting.

If a header bearing the same name is already present in the client request, it is honored and this plugin will not temper with it.

Generators

uuid

Format:

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Using this format, a UUID is generated in its hexadecimal form for each request.

uuid#counter

Format:

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx#counter

In this format, a single UUID is generated on a per-worker basis, and further requests simply append a counter to the UUID after a # character. The counter value starts at 0 for each worker, and gets incremented independently of the others.

This format provides a better performance, but might be harder to store or process for analyzing (due to its format and low cardinality).

tracker

Format:

ip-port-pid-connection-connection_requests-timestamp

In this format, the correlation id contains more practical implications for each request.

The following is a detailed description of the field

form parameter description
ip an address of the server which accepted a request
port port of the server which accepted a request
pid pid of the nginx worker process
connection connection serial number
connection_requests current number of requests made through a connection
timestamp a floating-point number for the elapsed time in seconds (including milliseconds as the decimal part) from the epoch for the current time stamp from the nginx cached time

FAQ

Can I see my correlation ids in my Kong logs?

The correlation id will not show up in the Nginx access or error logs. As such, we suggest you use this plugin alongside one of the Logging plugins, or store this id on your backend-side.