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Rate Limiting Policy

Rate Limiting Policy

Scenario

Users can set the rate limiting policy in the provider's configuration. By setting the request frequency from a particular micro service, provider can limit the max number of requests per second.

Cautions

  1. There may be a small difference between the rate limit and actual traffic.
  2. The provider's rate limit control is for service rather than security. To prevent distributed denial of service(DDos) attacks, you need to take other measures.
  3. Traffic control is scoped to microservice rather than instance. Consume a consumer microservice has 3 instances, and calls a provider service. After configuring the rate limit policy, the provider won't distinguish which consumer instance makes the request, but take all requests together as the 'consume request' for rate limiting.

Configuration

Rate limiting policies are configured in the microservice.yaml file. The table below shows all the configuration items. To enable the provider's rate limit policy, you also need to configure the rate limiting handler in the server's handler chain and add dependencies in the pom.xml file.

  • An example of rate limit configuration in microservice.yaml:
servicecomb:
  handler:
    chain:
      Provider:
        default: qps-flowcontrol-provider
  • Add the handler-flowcontrol-qps dependency in the pom.xml file:
<dependency>
    <groupId>org.apache.servicecomb</groupId>
    <artifactId>handler-flowcontrol-qps</artifactId>
    <version>1.0.0-m1</version>
</dependency>

QPS rate limit configuration items

Configuration Item Default Value Value Range Required Description Remarks
servicecomb.flowcontrol.Provider.qps.enabled true true/false No Enable provider's traffic control or not -
servicecomb.flowcontrol.Provider.qps.limit.[ServiceName] 2147483647（max int） (0,2147483647]，Integer No Specifies the number of requests allowed per second. This parameter can be configured to microservice/schema/operation, the latter has a higher priorty
servicecomb.flowcontrol.Provider.qps.global.limit 2147483647（max int） (0,2147483647]，Integer No Specifies the provider's total number of requests If no configuration is set for any specific microservice, this parameter takes effect

Notes:

The ServiceName in provider's rate limit config is the name of the consumer that calls the provider. While schema and operation is the provider's own config item. That is, the rate limit policy controls the consumer requests that call the provider's schema or operation.