Rate limit requests based on peak and off-peak time

Uses: Kong Gateway decK

Deployment Platform:

Prerequisites

Kong Konnect

This is a Konnect tutorial. If you don’t have a Konnect account, you can get started quickly with our onboarding wizard.

The following Konnect items are required to complete this tutorial:
- Personal access token (PAT): Create a new personal access token by opening the Konnect PAT page and selecting Generate Token.
- Control Plane Name: You can use an existing Control Plane or create a new one to use for this tutorial.
- Konnect Proxy URL: By default, a self-hosted Data Plane uses http://localhost:8000. You can set up Data Plane nodes for your Control Plane from the Gateway Manager in Konnect.

Set the personal access token, the Control Plane name, the Control Plane URL, and the Konnect proxy URL as environment variables:

 export DECK_KONNECT_TOKEN='YOUR KONNECT TOKEN'
 export DECK_KONNECT_CONTROL_PLANE_NAME='YOUR CONTROL PLANE NAME'
 export KONNECT_CONTROL_PLANE_URL=https://us.api.konghq.com
 export KONNECT_PROXY_URL='KONNECT PROXY URL'

Kong Gateway running

This tutorial requires Kong Gateway Enterprise. If you don’t have Kong Gateway set up yet, you can use the quickstart script with an enterprise license to get an instance of Kong Gateway running almost instantly.

Export your license to an environment variable:

 export KONG_LICENSE_DATA='LICENSE-CONTENTS-GO-HERE'

Run the quickstart script:

 curl -Ls https://get.konghq.com/quickstart | bash -s -- -e KONG_LICENSE_DATA 

Once Kong Gateway is ready, you will see the following message:

 Kong Gateway Ready

decK

decK is a CLI tool for managing Kong Gateway declaratively with state files. To complete this tutorial you will first need to install decK.

Pre-configured entities

For this tutorial, you’ll need Kong Gateway entities, like Gateway Services and Routes, pre-configured. These entities are essential for Kong Gateway to function but installing them isn’t the focus of this guide. Follow these steps to pre-configure them:

Run the following command:

echo '
_format_version: "3.0"
services:
  - name: example-service
    url: http://httpbin.konghq.com/anything
' | deck gateway apply -

To learn more about entities, you can read our entities documentation.

Create peak and off-peak Routes

Create a Route to handle peak traffic, and a Route to handle off-peak traffic. We’re going to use headers to distinguish between traffic times.

Attach both Routes to the example-service you created in the prerequisites.

echo '
_format_version: "3.0"
routes:
  - name: peak
    service:
      name: example-service
    paths:
    - "/anything"
    headers:
      X-Peak:
      - active
  - name: off-peak
    service:
      name: example-service
    paths:
    - "/anything"
    headers:
      X-Off-Peak:
      - active
' | deck gateway apply -

Apply Rate Limiting Advanced plugin

Apply rate limits to both Routes by enabling the Rate Limiting Advanced plugin on each Route:

echo '
_format_version: "3.0"
plugins:
  - name: rate-limiting-advanced
    route: peak
    config:
      limit:
      - 10
      window_size:
      - 30
      namespace: peak
  - name: rate-limiting-advanced
    route: off-peak
    config:
      limit:
      - 5
      window_size:
      - 30
      namespace: off-peak
' | deck gateway apply -

Apply the Pre-function plugin to route peak and off-peak traffic

The Pre-Function plugin lets you run Lua code in a plugin phase of your choosing. In this case, we’re going to write a function that determines the time of day based on the operating system’s time, then sets a request header based on the determined time.

You can set the hours based on your own preferred peak times.

The following command applies the Pre-Function globally and runs it in the rewrite phase:

echo '
_format_version: "3.0"
plugins:
  - name: pre-function
    config:
      rewrite:
      - |
        local hour = os.date("*t").hour
        if hour >= 8 and hour <= 17
        then
          kong.service.request.set_header("X-Peak","active")
        else
          kong.service.request.set_header("X-Off-Peak","active")
        end
' | deck gateway apply -

Validate

You can now verify that both plugins were configured correctly and are working, by sending more requests than allowed in the configured time limit.

Let’s send 11 requests, which will cover both the off-peak and peak rate limits:

for _ in {1..11}; do
  curl  -i $KONNECT_PROXY_URL/anything  
  echo
done

for _ in {1..11}; do
  curl  -i http://localhost:8000/anything  
  echo
done

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

Depending on your OS time, you will see either the X-Peak or X-Off-Peak header in the request, and you will hit the rate limit at either 6 or 11 requests.

Cleanup

Clean up Konnect environment

If you created a new control plane and want to conserve your free trial credits or avoid unnecessary charges, delete the new control plane used in this tutorial.

Destroy the Kong Gateway container

curl -Ls https://get.konghq.com/quickstart | bash -s -- -d