Throttle APIs with different rate limits for Services and Consumers

In this tutorial, we’ll be creating two Consumers that have different rate limits from the limits applied to the Gateway Service. These Consumers act as a type of “privileged” Consumer in this scenario that have higher rate limits, but they will still be prevented from exceeding the Service rate limits. The reason for this is to prevent DDoS type attacks on your APIs.

echo '
_format_version: "3.0"
consumers:
  - username: jsmith
    keyauth_credentials:
    - key: jsmith-key
  - username: tsmith
    keyauth_credentials:
    - key: tsmith-key
' | deck gateway apply -

Authentication lets you identify a Consumer so that you can apply rate limiting to Consumers. This example uses the Key Authentication plugin, but you can use any authentication plugin that you prefer.

Enable the plugin globally, which means it applies to all Kong Gateway Services and Routes:

echo '
_format_version: "3.0"
plugins:
  - name: key-auth
    config:
      key_names:
      - apikey
' | deck gateway apply -

Enable the Rate Limiting plugin for the Consumers. In this example, the limit is 6 requests per minute per Consumer.

echo '
_format_version: "3.0"
plugins:
  - name: rate-limiting
    consumer: jsmith
    config:
      minute: 6
      limit_by: consumer
      policy: local
  - name: rate-limiting
    consumer: tsmith
    config:
      minute: 6
      limit_by: consumer
      policy: local
' | deck gateway apply -

Now we can apply a rate limit on the Service itself using the Service Protection plugin. In this example, we are setting the limit to 10 requests per minute. Due to plugin execution order, the Service Protection plugin is applied before the Rate Limiting plugin. This means that if multiple Consumers are making requests at the same time, together they can’t make more than 10 requests per minute, even if the individual Consumer rate limit is 6 requests per minute.

echo '
_format_version: "3.0"
plugins:
  - name: service-protection
    service: example-service
    config:
      window_size:
      - 60
      limit:
      - 10
      namespace: service-protection-plugin
' | deck gateway apply -

To test that the Service Protection plugin correctly applies rate limits to the Service, you’ll run requests from both Consumers in quick succession.

First, run the following command to test the rate limiting as the jsmith Consumer:

for _  in {1..6}; do
 curl "$KONNECT_PROXY_URL/anything" \
     -H "apikey:jsmith-key"done

for _  in {1..6}; do
 curl "http://localhost:8000/anything" \
     -H "apikey:jsmith-key"done

This doesn’t exceed the rate limit per Consumer or per Service.

Now, quickly run the following command to test the rate limiting as the tsmith Consumer:

for _ in {1..5}; do
  curl  -i $KONNECT_PROXY_URL/anything \
       -H "apikey:tsmith-key" 
  echo
done

for _ in {1..5}; do
  curl  -i http://localhost:8000/anything \
       -H "apikey:tsmith-key" 
  echo
done

On the last request, you should get a 429 response with the message API rate limit exceeded.

You get this error because the Consumer has now exceeded the rate limit of 10 requests per minute on the Service.