apply-rate-limiting-to-api.md

Applying Ratelimiting to APIs

Ratelimiting policies can be applied to the APIs created with the kubernetes operator, to throttle out requests according to the desired limit.

Ratelimiting controller obtains the policies in the below 2 methods.

• User defined policies
• Set of default policies

The Ratelimiting controller uses the policies deployed to create a policy template configmap, which gets updated when user deploy Ratelimiting policies. This policy cofigmap is mounted to kaniko job by the API controller and used to create the docker image.

How to deploy a Ratelimiting policy

Create a Ratelimiting policy using the Ratelimiting kind. You can create 3 types of policies with the Ratelimiting kind as shown below. Include the limit from which you want to throttle the API requests.

Note: When an API refers a Ratelimiting policy in swagger definition under x-wso2-throttling-tier keyword you need to make sure that the namespace that you have provided the Ratelimiting policy is same as the namespace of the API.

Example: In the following Ratelimiting policies the namespace is provided as "wso2-test-ns". Therefore the namespace of the API that these Ratelimiting policies are being referred should be "wso2-test-ns".

• Application throttling

  apiVersion: wso2.com/v1alpha1
  kind: RateLimiting
  metadata:
    name: app4
    namespace: wso2-test-ns
  spec:
    type: application             
    description: Allow 4 requests per minute   # optional
    timeUnit: min
    unitTime: 1
    requestCount:
     limit: 4

• Subscription throttling

  apiVersion: wso2.com/v1alpha1
  kind: RateLimiting
  metadata:
    name: sub6
    namespace: wso2-test-ns
  spec:
    type: subscription             
    description: Allow 6 requests per minute   # optional
    timeUnit: min
    unitTime: 1
    requestCount:
     limit: 6

• Advance throttling

  apiVersion: wso2.com/v1alpha1
  kind: RateLimiting
  metadata:
    name: advance3
    namespace: wso2-test-ns
  spec:
    type: advance             
    description: Allow 3 requests per minute   # optional
    timeUnit: min
    unitTime: 1
    requestCount:
     limit: 3

Implementation of the Ratelimiting controller is found here

Sample Ratelimiting definitions are provided here.