Skip to content
|
search
Plugin Hub
header icon

CORS

Easily add cross-origin resource sharing (CORS) to a Service and a Route by enabling this plugin.

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

The following examples provide some typical configurations for enabling the cors plugin on a service.

Make the following request:

curl -X POST http://localhost:8001/services/SERVICE_NAME|SERVICE_ID/plugins \
    --data "name=cors"  \
    --data "config.origins=http://mockbin.com" \
    --data "config.methods=GET" \
    --data "config.methods=POST" \
    --data "config.headers=Accept" \
    --data "config.headers=Accept-Version" \
    --data "config.headers=Content-Length" \
    --data "config.headers=Content-MD5" \
    --data "config.headers=Content-Type" \
    --data "config.headers=Date" \
    --data "config.headers=X-Auth-Token" \
    --data "config.exposed_headers=X-Auth-Token" \
    --data "config.credentials=true" \
    --data "config.max_age=3600"

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: cors-example
config: 
  origins:
  - http://mockbin.com
  methods:
  - GET
  - POST
  headers:
  - Accept
  - Accept-Version
  - Content-Length
  - Content-MD5
  - Content-Type
  - Date
  - X-Auth-Token
  exposed_headers:
  - X-Auth-Token
  credentials: true
  max_age: 3600
plugin: cors

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: cors-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: cors
  service: SERVICE_NAME|SERVICE_ID
  config: 
    origins:
    - http://mockbin.com
    methods:
    - GET
    - POST
    headers:
    - Accept
    - Accept-Version
    - Content-Length
    - Content-MD5
    - Content-Type
    - Date
    - X-Auth-Token
    exposed_headers:
    - X-Auth-Token
    credentials: true
    max_age: 3600

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

You can configure this plugin through the Konnect UI.

From the servicehub icon Service Hub, select a service version, then set up the plugin:

  1. In the Plugins section, click Add Plugin.
  2. Find and select the CORS plugin.

  3. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Credentials: select checkbox
  4. Click Create.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. From the Services section, click View for the service row.
  3. From the plugin section, click Add Plugin.
  4. Find and select the CORS plugin.
  5. If the option is available, select Scoped.
  6. Add the service name and ID to the Service field if it is not already pre-filled.

  7. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Credentials: select checkbox
  8. Click Create.

The following examples provide some typical configurations for enabling the cors plugin on a route.

Make the following request:

curl -X POST http://localhost:8001/routes/ROUTE_NAME|ROUTE_ID/plugins \
  --data "name=cors"  \
    --data "config.origins=http://mockbin.com" \
    --data "config.methods=GET" \
    --data "config.methods=POST" \
    --data "config.headers=Accept" \
    --data "config.headers=Accept-Version" \
    --data "config.headers=Content-Length" \
    --data "config.headers=Content-MD5" \
    --data "config.headers=Content-Type" \
    --data "config.headers=Date" \
    --data "config.headers=X-Auth-Token" \
    --data "config.exposed_headers=X-Auth-Token" \
    --data "config.credentials=true" \
    --data "config.max_age=3600"

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: cors-example
config: 
  origins:
  - http://mockbin.com
  methods:
  - GET
  - POST
  headers:
  - Accept
  - Accept-Version
  - Content-Length
  - Content-MD5
  - Content-Type
  - Date
  - X-Auth-Token
  exposed_headers:
  - X-Auth-Token
  credentials: true
  max_age: 3600
plugin: cors

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: cors-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: cors
  route: ROUTE_NAME
  config: 
    origins:
    - http://mockbin.com
    methods:
    - GET
    - POST
    headers:
    - Accept
    - Accept-Version
    - Content-Length
    - Content-MD5
    - Content-Type
    - Date
    - X-Auth-Token
    exposed_headers:
    - X-Auth-Token
    credentials: true
    max_age: 3600

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

You can configure this plugin through the Konnect UI.

From the servicehub icon Service Hub, select a service version, then set up the plugin:

  1. Select a route.
  2. In the Plugins section, click Add Plugin.
  3. Find and select the CORS plugin.

  4. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Credentials: select checkbox
  5. Click Create.

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. Open Routes from the menu, then click View for the route row.
  3. From the plugin section, click Add Plugin.
  4. Find and select the CORS plugin.
  5. If the option is available, select Scoped.
  6. Add the route ID if it is not already prefilled.

  7. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Credentials: select checkbox
  8. Click Create.

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 cors plugin globally.

Make the following request:

curl -X POST http://localhost:8001/plugins/ \
  --data "name=cors"  \
    --data "config.origins=http://mockbin.com" \
    --data "config.methods=GET" \
    --data "config.methods=POST" \
    --data "config.headers=Accept" \
    --data "config.headers=Accept-Version" \
    --data "config.headers=Content-Length" \
    --data "config.headers=Content-MD5" \
    --data "config.headers=Content-Type" \
    --data "config.headers=Date" \
    --data "config.headers=X-Auth-Token" \
    --data "config.exposed_headers=X-Auth-Token" \
    --data "config.credentials=true" \
    --data "config.max_age=3600"

Create a KongClusterPlugin resource and label it as global:

apiVersion: configuration.konghq.com/v1
kind: KongClusterPlugin
metadata:
  name: <global-cors>
  annotations:
    kubernetes.io/ingress.class: kong
  labels:
    global: \"true\"
config: 
  origins:
  - http://mockbin.com
  methods:
  - GET
  - POST
  headers:
  - Accept
  - Accept-Version
  - Content-Length
  - Content-MD5
  - Content-Type
  - Date
  - X-Auth-Token
  exposed_headers:
  - X-Auth-Token
  credentials: true
  max_age: 3600
plugin: cors

Add a plugins entry in the declarative configuration file:

plugins:
- name: cors
  config: 
    origins:
    - http://mockbin.com
    methods:
    - GET
    - POST
    headers:
    - Accept
    - Accept-Version
    - Content-Length
    - Content-MD5
    - Content-Type
    - Date
    - X-Auth-Token
    exposed_headers:
    - X-Auth-Token
    credentials: true
    max_age: 3600

You can configure this plugin through the Kong Manager UI.

  1. In Kong Manager, select the workspace.
  2. Open Plugins from the menu, then click New Plugin.
  3. Find and select the CORS plugin.
  4. If the option is available, set the plugin scope to Global.

  5. Configure the plugin’s parameters.

    You can test out the plugin with the following sample configuration:

    • Config.Credentials: select checkbox
  6. 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 cors.
service.name or service.id

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

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.
enabled

Type: boolean

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

Type: array of string elements

List of allowed domains for the Access-Control-Allow-Origin header. If you want to allow all origins, add * as a single value to this configuration field. The accepted values can either be flat strings or PCRE regexes.
config.methods
optional

Type: array of string elements

Default value: GET, HEAD, PUT, PATCH, POST, DELETE, OPTIONS, TRACE, CONNECT

Value for the Access-Control-Allow-Methods header. Available options include GET, HEAD, PUT, PATCH, POST, DELETE, OPTIONS, TRACE, CONNECT. By default, all options are allowed.
config.headers
optional

Type: array of string elements

Default value: Value of the Access-Control-Request-Headers request header

Value for the Access-Control-Allow-Headers header.
config.exposed_headers
optional

Type: array of string elements

Value for the Access-Control-Expose-Headers header. If not specified, no custom headers are exposed.
config.credentials
required

Type: boolean

Default value: false

Flag to determine whether the Access-Control-Allow-Credentials header should be sent with true as the value.
config.max_age
optional

Type: number

Indicates how long the results of the preflight request can be cached, in seconds.
config.preflight_continue
required

Type: boolean

Default value: false

A boolean value that instructs the plugin to proxy the OPTIONS preflight request to the Upstream service.

Known issues

Below is a list of known issues or limitations for this plugin.

CORS Limitations

If the client is a browser, there is a known issue with this plugin caused by a limitation of the CORS specification that doesn’t allow to specify a custom Host header in a preflight OPTIONS request.

Because of this limitation, this plugin only works for Routes that have been configured with a paths setting. The CORS plugin does not work for Routes that are being resolved using a custom DNS (the hosts property).

To learn how to configure paths for a Route, read the Proxy Reference.