Route By Header plugin

Kong Gateway plugin to route requests based on request headers.

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

Example plugin configuration

Enable on a service

Enable on a route

Enable on a consumer

Enable globally

The following examples provide some typical configurations for enabling the route-by-header plugin on a service.

Admin API

Kubernetes

Declarative (YAML)

Make the following request:

curl -X POST http://localhost:8001/services/SERVICE_NAME|SERVICE_ID/plugins \
    --data "name=route-by-header" 

Replace SERVICE_NAME|SERVICE_ID with 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: route-by-header-example
config:
  EXAMPLE_PARAMETER: EXAMPLE_VALUE
plugin: route-by-header

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

apiVersion: v1
kind: Service
metadata:
  name: SERVICE_NAME|SERVICE_ID
  labels:
    app: SERVICE_NAME|SERVICE_ID
  annotations:
    konghq.com/plugins: route-by-header-example
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: SERVICE_NAME|SERVICE_ID
  selector:
    app: SERVICE_NAME|SERVICE_ID

Replace SERVICE_NAME|SERVICE_ID with 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.

Add this section to your declarative configuration file:

plugins:
- name: route-by-header
  service: SERVICE_NAME|SERVICE_ID
  config:
    EXAMPLE_PARAMETER: EXAMPLE_VALUE

Replace SERVICE_NAME|SERVICE_ID with the id or name of the service that this plugin configuration will target.

The following examples provide some typical configurations for enabling the route-by-header plugin on a route.

Admin API

Kubernetes

Declarative (YAML)

Make the following request:

curl -X POST http://localhost:8001/routes/ROUTE_NAME|ROUTE_ID/plugins \
  --data "name=route-by-header" 

Replace ROUTE_NAME|ROUTE_ID with 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: route-by-header-example
config:
  EXAMPLE_PARAMETER: EXAMPLE_VALUE
plugin: route-by-header

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

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ROUTE_NAME|ROUTE_ID
  annotations:
    kubernetes.io/ingress.class: kong
    konghq.com/plugins: route-by-header-example
spec:
  rules:
  - host: examplehostname.com
    http:
      paths:
      - path: /bar
        backend:
          service:
            name: echo
            port:
              number: 80

Replace ROUTE_NAME|ROUTE_ID with 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.

Add this section to your declarative configuration file:

plugins:
- name: route-by-header
  route: ROUTE_NAME
  config:
    EXAMPLE_PARAMETER: EXAMPLE_VALUE

Replace ROUTE_NAME|ROUTE_ID with the id or name of the route that this plugin configuration will target.

The following examples provide some typical configurations for enabling the route-by-header plugin on a consumer.

Admin API

Kubernetes

Declarative (YAML)

Make the following request:

curl -X POST http://localhost:8001/consumers/CONSUMER_NAME|CONSUMER_ID/plugins \
  --data "name=route-by-header" 

Replace CONSUMER_NAME|CONSUMER_ID with the id or name 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: route-by-header-example
config:
  EXAMPLE_PARAMETER: EXAMPLE_VALUE
plugin: route-by-header

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

apiVersion: configuration.konghq.com/v1
kind: KongConsumer
metadata:
  name: CONSUMER_NAME|CONSUMER_ID
  annotations:
    konghq.com/plugins: route-by-header-example
    kubernetes.io/ingress.class: kong

Replace CONSUMER_NAME|CONSUMER_ID with the id or name 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.

Add this section to your declarative configuration file:

plugins:
- name: route-by-header
  consumer: CONSUMER_NAME|CONSUMER_ID
  config:
    EXAMPLE_PARAMETER: EXAMPLE_VALUE

Replace CONSUMER_NAME|CONSUMER_ID with the id or name of the consumer that this plugin configuration will target.

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.

The following examples provide some typical configurations for enabling the route-by-header plugin globally.

Admin API

Kubernetes

Declarative (YAML)

Make the following request:

curl -X POST http://localhost:8001/plugins/ \
  --data "name=route-by-header" 

Create a KongClusterPlugin resource and label it as global:

apiVersion: configuration.konghq.com/v1
kind: KongClusterPlugin
metadata:
  name: <global-route-by-header>
  annotations:
    kubernetes.io/ingress.class: kong
  labels:
    global: \"true\"
config:
  <optional_parameter>: <value>
plugin: route-by-header

Add a plugins entry in the declarative configuration file:

plugins:
- name: route-by-header
  config:
    EXAMPLE_PARAMETER: EXAMPLE_VALUE

Parameters

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

Form Parameter Description

Form Parameter	Description
`name` required Type: string	The name of the plugin, in this case `route-by-header`.
`service.name` or `service.id` optional Type: string	The name or ID of the service the plugin targets. Set one of these parameters if adding the plugin to a service through the top-level `/plugins` endpoint. Not required if using `/services/SERVICE_NAME\|SERVICE_ID/plugins`.
`route.name` or `route.id` optional Type: string	The name or ID of the route the plugin targets. Set one of these parameters if adding the plugin to a route through the top-level `/plugins` endpoint. Not required if using `/routes/ROUTE_NAME\|ROUTE_ID/plugins`.
`consumer.name` or `consumer.id` optional Type: string	The name or ID of the consumer the plugin targets. Set one of these parameters if adding the plugin to a consumer through the top-level `/plugins` endpoint. Not required if using `/consumers/CONSUMER_NAME\|CONSUMER_ID/plugins`.
`enabled` optional Type: boolean Default value: `true`	Whether this plugin will be applied.
`config.rules` optional Default value: `{}`	List of rules

name

required

Type: string

The name of the plugin, in this case route-by-header.

service.name or service.id

optional

Type: string

The name or ID of the service the plugin targets.

Set one of these parameters if adding the plugin to a service through the top-level /plugins endpoint.

Not required if using /services/SERVICE_NAME|SERVICE_ID/plugins.

route.name or route.id

optional

Type: string

The name or ID of the route the plugin targets.

Set one of these parameters if adding the plugin to a route through the top-level /plugins endpoint.

Not required if using /routes/ROUTE_NAME|ROUTE_ID/plugins.

consumer.name or consumer.id

optional

Type: string

The name or ID of the consumer the plugin targets.

Set one of these parameters if adding the plugin to a consumer through the top-level /plugins endpoint.

Not required if using /consumers/CONSUMER_NAME|CONSUMER_ID/plugins.

enabled

optional

Type: boolean

Default value: true

Whether this plugin will be applied.

config.rules

optional

Default value: {}

List of rules

Rules

parameter	description
`condition`	List of headers name and value pairs
`upstream_name`	Target hostname where traffic will be routed in case of condition match

Note: If more than one pair of header name and value is provided, the plugin looks for all of these in the request - that is, requests must contain all of the specified headers with the specified values for a match to occur.

Usage

The plugin will route a request to a new upstream target if it matches one of the configured rules. Each rule consists of a condition object and an upstream_name object. For each request coming into Kong, the plugin will try to find a rule where all the headers defined in the condition field have the same value as in the incoming request. The first such match dictates the upstream to which the request is forwarded to.

Example

Let’s run through an example scenario to demonstrate the plugin. Let’s say we have a Kong service serviceA, which routes all the requests to upstream default.domain.com.

Add an upstream object and a target:

curl -i -X POST http://kong:8001/upstreams -d name=default.domain.com

Response:

HTTP/1.1 201 Created
...
{created_at":1534537731231, .. "slots":10000}

curl -i -X POST http://kong:8001/upstreams/default.domain.com/targets --data target="default.host.com:9000"

Response:

HTTP/1.1 201 Created
...
{"created_at":1534538010468, .. ,"id":"ffd8815b-fd6c-4e0e-aa67-06e9cda39c3b"}

Now we will add a service and a route object, using the upstream default.domain.com we just created:

curl -i -X POST http://kong:8001/services --data protocol=http --data host=default.domain.com --data name=serviceA

Response:

HTTP/1.1 201 Created
...
{"host":"default.domain.com", .. ,"write_timeout":60000}

curl -i -X POST http://kong:8001/routes  --data "paths[]=/" --data service.id=6e7f5274-62da-469e-bdd5-03c4a212c15b

Response:

HTTP/1.1 201 Created
...
{"created_at":1534538701, .. ,"id":"12ceb66b-51ed-488a-9de0-112270e6f370"}

Now any request made to service serviceA will be routed to the upstream default.domain.com. But let’s say we want to route some of these requests to different upstreams, dynamically, based on some information provided through request headers. This is the exact situation where this plugin can be helpful.

Let’s apply this plugin on serviceA to route all requests with a header Location set to us-east to upstream east.domain.com and requests with a header Location set to us-west to upstream west.domain.com.

Add the two upstreams and corresponding targets:

curl -i -X POST http://localhost:8001/upstreams -d name=east.domain.com

Response:

HTTP/1.1 201 Created
...
{"created_at":1534541064946, .. ,"slots":10000}

curl -i -X POST http://kong:8001/upstreams/east.domain.com/targets --data target="east.host.com:9001"

Response:

HTTP/1.1 201 Created
...
{"created_at":1534541248416, .. ,"id":"3164a588-09d7-4a72-895f-fa19535e3682"}

curl -i -X POST http://localhost:8001/upstreams -d name=west.domain.com

Response:

HTTP/1.1 201 Created
...
{"created_at":1534541385227, .. ,"slots":10000}

curl -i -X POST http://kong:8001/upstreams/west.domain.com/targets --data target="west.host.com:9002"

Response:

HTTP/1.1 201 Created
...
{"created_at":1534541405038, .. ,"id":"96cb469f-280f-4b0a-bd3d-1a0599b82585"}

Enable plugin on service serviceA:

curl -i -X POST http://kong:8001/services/serviceA/plugins \
  -H 'Content-Type: application/json' \
  --data '{"name": "route-by-header", "config": {"rules":[{"condition": {"location":"us-east"}, "upstream_name": "east.domain.com"}, {"condition": {"location":"us-west"}, "upstream_name": "west.domain.com"}]}}'

Response:

HTTP/1.1 201 Created
...
{"created_at":1534540916000,"config":{"rules":{"":"{\"condition\": {\"location\":\"us-east\"}, \"upstream_name\": \"east.domain.com\"}, {\"condition\": {\"location\":\"us-west\"}, \"upstream_name\": \"west.domain.com\"}"}},"id":"0df16085-76b2-4a50-ac30-c8a1eade389a","enabled":true,"service_id":"6e7f5274-62da-469e-bdd5-03c4a212c15b","name":"route-by-header"}

Now, any request with header Location set to us-east will route to upstream east.domain.com and requests with header Location set to us-west will route to upstream west.domain.com.

You can also provide multiple headers as matching condition. The plugin does an AND on the provided headers in the condition field of each rule.

Let’s patch above plugin to add one more rule with multiple headers:

curl -i -X PATCH http://kong:8001/plugins/0df16085-76b2-4a50-ac30-c8a1eade389a \
  -H 'Content-Type: application/json' \
  --data '{"name": "route-by-header", "config": {"rules":[{"condition": {"location":"us-east"}, "upstream_name": "east.domain.com"}, {"condition": {"location":"us-west"}, "upstream_name": "west.domain.com"},  {"condition": {"location":"us-south", "region": "US"}, "upstream_name": "south.domain.com"}]}}'

Response:

HTTP/1.1 200 OK
...
{"created_at":1534540916000,"config":{"rules":{"":"{\"condition\": {\"location\":\"us-east\"}, \"upstream_name\": \"east.domain.com\"}, {\"condition\": {\"location\":\"us-west\"}, \"upstream_name\": \"west.domain.com\"}, {\"condition\": {\"location\":\"us-south\", \"region\": \"us\"}, \"upstream_name\": \"south.domain.com\"}"}},"id":"0df16085-76b2-4a50-ac30-c8a1eade389a","enabled":true,"service_id":"6e7f5274-62da-469e-bdd5-03c4a212c15b","name":"route-by-header"}

Now we have an additional rule which routes any request with header Location set to us-south and Region set to US route to upstream south.domain.com.

About this Plugin
Plugin Version	0.3.2
Made by	Kong Inc.
Categories	Traffic Control
DB-less compatible?	Yes
Konnect Cloud compatible?	See latest plugin version
Compatible protocols	`http` `https` `grpc` `grpcs`