API Gateway Flow Control

Sentinel supports flow control for API gateways like Spring Cloud Gateway and Zuul 1.x.

Spring Cloud Gateway

Sentinel provides the integration module with Spring Cloud Gateway, providing two levels of flow control:

• Route level: flow control for defined routes in Spring properties file.
• Customized API group level: flow control for customized API groups defined in GatewayApiDefinitionManager of Sentinel.

Add the following dependency in pom.xml (if you are using Maven):

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
    <version>x.y.z</version>
</dependency>

Then you only need to inject the corresponding SentinelGatewayFilter and SentinelGatewayBlockExceptionHandler instance in Spring configuration. For example:

@Configuration
public class GatewayConfiguration {

    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;

    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    @Bean
    @Order(-1)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        // Register the block exception handler for Spring Cloud Gateway.
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    @Bean
    public GlobalFilter sentinelGatewayFilter() {
        // By default the order is HIGHEST_PRECEDENCE
        return new SentinelGatewayFilter();
    }
}

The gateway adapter will regard all routeId (defined in Spring properties) and all customized API definitions (defined in GatewayApiDefinitionManager of sentinel-api-gateway-adapter-common module) as resources.

You can register various kinds of customized callback in GatewayCallbackManager:

• setBlockHandler: register a customized BlockRequestHandler to handle the blocked request. The default implementation is DefaultBlockRequestHandler, which returns default message like Blocked by Sentinel: FlowException.

Zuul 1.x

Sentinel provides the integration module with Zuul 1.x, providing two levels of flow control:

• Route level: flow control for defined routes in Zuul properties file.
• Customized API group level: flow control for customized API groups defined in GatewayApiDefinitionManager of Sentinel.

To introduce Sentinel to your Zuul gateway, add the following dependency in pom.xml (if you are using Maven):

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-zuul-adapter</artifactId>
    <version>x.y.z</version>
</dependency>

Then for Spring Cloud Zuul users, we only need to inject the three filters in Spring configuration class like this:

@Configuration public class ZuulConfig {

@Bean
public ZuulFilter sentinelZuulPreFilter() {
    // We can provider the filter order here.
    return new SentinelZuulPreFilter(10000);
}

@Bean
public ZuulFilter sentinelZuulPostFilter() {
    return new SentinelZuulPostFilter(1000);
}

@Bean
public ZuulFilter sentinelZuulErrorFilter() {
    return new SentinelZuulErrorFilter(-1);
}

}

The dashboard of gateway flow control