Response Rate Limiting

This plugin allows you to limit the number of requests a developer can make based on a custom response header returned by the upstream service. You can arbitrary set as many rate-limiting objects (or quotas) as you want and instruct IAM to increase or decrease them by any number of units. Each custom rate-limiting object can limit the inbound requests per seconds, minutes, hours, days, months or years.

If the underlying Service/Route (or deprecated API entity) has no authentication layer, the Client IP address will be used, otherwise the Consumer will be used if an authentication plugin has been configured.

Terminology

• plugin: a plugin executing actions inside IAM before or after a request has been proxied to the upstream API.
• Service: the IAM entity representing an external upstream API or microservice.
• Route: the IAM entity representing a way to map downstream requests to upstream services.
• Consumer: the IAM entity representing a developer or machine using the API. When using IAM, a Consumer only communicates with IAM which proxies every call to the said upstream API.
• Credential: a unique string associated with a Consumer, also referred to as an API key.
• upstream service: this refers to your own API/service sitting behind IAM, to which client requests are forwarded.
• API: a legacy entity used to represent your upstream services. Deprecated in favor of Services.

Configuration

This plugin is compatible with requests with the following protocols:

• http
• https

This plugin is partially compatible with DB-less mode.

Enabling the plugin on a Service

With a database

Configure this plugin on a Service by making the following request:

$ curl -X POST http://localhost:8001/services/{service}/plugins \
    --data "name=response-ratelimiting"  \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

Without a database

Configure this plugin on a Service by adding this section do your declarative configuration file:

plugins:
- name: response-ratelimiting
  service: {service}
  config:
    limits.{limit_name}:
    limits.{limit_name}.minute: 10

In both cases, {service} is the id or name of the Service that this plugin configuration will target.

Enabling the plugin on a Route

With a database

Configure this plugin on a Route with:

$ curl -X POST http://localhost:8001/routes/{route}/plugins \
    --data "name=response-ratelimiting"  \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

Without a database

Configure this plugin on a Route by adding this section do your declarative configuration file:

plugins:
- name: response-ratelimiting
  route: {route}
  config:
    limits.{limit_name}:
    limits.{limit_name}.minute: 10

In both cases, {route} is the id or name of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

With a database

You can use the http://localhost:8001/plugins endpoint to enable this plugin on specific Consumers:

$ curl -X POST http://localhost:8001/consumers/{consumer}/plugins \
    --data "name=response-ratelimiting" \
     \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

Without a database

Configure this plugin on a Consumer by adding this section do your declarative configuration file:

plugins:
- name: response-ratelimiting
  consumer: {consumer}
  config:
    limits.{limit_name}:
    limits.{limit_name}.minute: 10

In both cases, {consumer} is the id or username of the Consumer that this plugin configuration will target.

You can combine consumer_id and service_id

in the same request, to furthermore narrow the scope of the plugin.

Global plugins

• Using a database, all plugins can be configured using the http://localhost:8001/plugins/ endpoint.
• Without a database, all plugins can be configured via the plugins: entry on the declarative configuration file.

A plugin which is not associated to any Service, Route or Consumer (or API, if you are using an older version of IAM) is considered "global", and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

Parameters

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

Configuring Quotas

After adding the plugin, you can increment the configured limits by adding the following response header:

Header-Name: Limit=Value [,Limit=Value]

Since X-Kong-Limit is the default header name (you can optionally change it), it will look like:

X-Kong-Limit: limitname1=2, limitname2=4

That will increment the limit limitname1 by 2 units, and limitname2 by 4 units.

You can optionally increment more than one limit by comma separating the entries. The header will be removed before returning the response to the original client.

Headers sent to the client

When this plugin is enabled, IAM will send some additional headers back to the client telling how many units are available and how many are allowed. For example if you created a limit/quota called “Videos” with a per-minute limit:

X-RateLimit-Limit-Videos-Minute: 10
X-RateLimit-Remaining-Videos-Minute: 9

or it will return a combination of more time limits, if more than one is being set:

X-RateLimit-Limit-Videos-Second: 5
X-RateLimit-Remaining-Videos-Second: 5
X-RateLimit-Limit-Videos-Minute: 10
X-RateLimit-Remaining-Videos-Minute: 10

If any of the limits configured is being reached, the plugin will return a HTTP/1.1 429 status code and an empty body.

Upstream Headers

The plugin will append the usage headers for each limit before proxying it to the upstream service, so that you can properly refuse to process the request if there are no more limits remaining. The headers are in the form of X-RateLimit-Remaining-{limit_name}, like:

X-RateLimit-Remaining-Videos: 3
X-RateLimit-Remaining-Images: 0