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Correlation ID

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

Configuration Reference

This plugin is compatible with DB-less mode.

In DB-less mode, you configure Kong Gateway declaratively. Therefore, the Admin API is mostly read-only. The only tasks it can perform are all related to handling the declarative config, including:

  • Setting a target's health status in the load balancer
  • Validating configurations against schemas
  • Uploading the declarative configuration using the /config endpoint

Enable the plugin on a service

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

curl -X POST http://{HOST}: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"

SERVICE is the id or name of the service that this plugin configuration will target.

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}

{SERVICE} is the id or name of the service that this plugin configuration will target.

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.

Configure this plugin on a service:

  1. In Konnect Cloud, select the service on the ServiceHub page.
  2. Scroll down to Versions and select the version.
  3. Scroll down to Plugins and click New Plugin.
  4. Find and select the Correlation ID plugin.

  5. Enter the following parameters, updating the default or sample values as needed:

    • Config.Header Name: Kong-Request-ID
    • Config.Generator: uuid#counter
    • Config.Echo Downstream: clear checkbox
  6. Click Create.

Configure this plugin on a service:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, scroll down to Services and click View for the service row.
  3. Scroll down to plugins and click Add Plugin.

  4. Find and select the Correlation ID plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  5. If the option is available, select Scoped.
  6. Add the service name and ID to the Service field if it is not already prefilled.

  7. Enter the following parameters, updating the default or sample values as needed:

    • Config.Header Name: Kong-Request-ID
    • Config.Generator: uuid#counter
    • Config.Echo Downstream: clear checkbox
  8. Click Create.

Enable the plugin on a route

For example, configure this plugin on a route with:

$ curl -X POST http://{HOST}: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"

ROUTE is the id or name of the route that this plugin configuration will target.

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

ROUTE is the id or name of the route that this plugin configuration will target.

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.

Configure this plugin on a route:

  1. In Konnect Cloud, select the service from the ServiceHub page.
  2. Scroll down to Versions and select the version.
  3. Select the route.
  4. Scroll down to Plugins and click Add Plugin.
  5. Find and select the Correlation ID plugin.

  6. Enter the following parameters, updating the default or sample values as needed:

    • Config.Header Name: Kong-Request-ID
    • Config.Generator: uuid#counter
    • Config.Echo Downstream: clear checkbox
  7. Click Create.

Configure this plugin on a route:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, select Routes in the left navigation.
  3. Click View for the route row.
  4. Scroll down to plugins and click Add Plugin.

  5. Find and select the Correlation ID plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  6. If the option is available, select Scoped.
  7. Add the Route ID if it is not already prefilled.

  8. Enter the following parameters, updating the default or sample values as needed:

    • Config.Header Name: Kong-Request-ID
    • Config.Generator: uuid#counter
    • Config.Echo Downstream: clear checkbox
  9. Click Create.

Enabling the plugin on a consumer

For example, configure this plugin on a consumer with:

$ curl -X POST http://{HOST}: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"

CONSUMER is the id or username of the consumer that this plugin configuration will target.

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

CONSUMER is the id or username of the consumer that this plugin configuration will target.

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.

Configure this plugin on a consumer:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, scroll down to Consumers and click View for the consumer row.
  3. Select the Plugins tab.
  4. Click Add Plugin.

  5. Find and select the Correlation ID plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  6. If the option is available, select Global.

  7. Enter the following parameters, updating the default or sample values as needed:

    • Config.Header Name: Kong-Request-ID
    • Config.Generator: uuid#counter
    • Config.Echo Downstream: clear checkbox
  8. Click Create.

Enable 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.

For example, configure this plugin globally with:

$ curl -X POST http://{HOST}: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

Configure this plugin globally:

  1. In Kong Manager, select the workspace.
  2. From the Dashboard, select Plugins in the left navigation.
  3. Click New Plugin.

  4. Find and select the Correlation ID plugin.

    Note: If the plugin is greyed out, then it is not available for your product tier. See Kong Gateway tiers.
  5. If the option is available, set the plugin scope to Global.

  6. Enter the following parameters, updating the default/sample values as needed:

    • Config.Header Name: Kong-Request-ID
    • Config.Generator: uuid#counter
    • Config.Echo Downstream: clear checkbox
  7. Click Create.

Parameters

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

Form Parameter Description
name
required

Type: string		 The name of the plugin, 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
required

Type: boolean

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

Type: string

Default value: Kong-Request-ID

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

Type: string

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
required

Type: boolean

Default value: false

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

How it works

When you enable this plugin, it adds 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 is generated according to config.generator.

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

If a header with the same name is already present in the client request, the plugin honors it and does not tamper with it.

Generators

uuid

Format:

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

This format generates a heaxadecimal UUID for each request.

uuid#counter

Format:

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx#counter

This format generates a single UUID on a per-worker basis, and further the 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 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

This 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 that accepts a request
port port of the server that accepts 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 timestamp from the nginx cached time

FAQ

Can I see my correlation ids in my Kong logs?

The correlation id doesn’t show up in the Nginx access or error logs. However, you can use this plugin along with one of the Logging plugins, or store the id on your backend.