Sentinel/sentinel-adapter/sentinel-spring-webmvc-adapter

Sentinel Spring MVC Interceptor

Sentinel provides Spring MVC Interceptor integration to enable flow control for web requests, And support url like '/foo/{id}'

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

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

Configure interceptor

@Configuration
public class InterceptorConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //Add sentinel interceptor
        addSpringMvcInterceptor(registry);
        //If you want to sentinel the total flow, you can add total interceptor
        addSpringMvcTotalInterceptor(registry);
    }

    private void addSpringMvcInterceptor(InterceptorRegistry registry) {
        //Configure
        SentinelWebMvcConfig config = new SentinelWebMvcConfig();
        //Custom configuration if necessary
        config.setHttpMethodSpecify(true);
        config.setOriginParser(request -> request.getHeader("S-user"));
        //Add sentinel interceptor
        registry.addInterceptor(new SentinelInterceptor(config)).addPathPatterns("/**");
    }

    private void addSpringMvcTotalInterceptor(InterceptorRegistry registry) {
        //Configure
        SentinelWebMvcTotalConfig config = new SentinelWebMvcTotalConfig();
        //Custom configuration if necessary
        config.setRequestAttributeName("my_sentinel_spring_mvc_total_entity_container");
        config.setTotalResourceName("my-spring-mvc-total-url-request");
        //Add sentinel interceptor
        registry.addInterceptor(new SentinelTotalInterceptor(config)).addPathPatterns("/**");
    }
}

Configure 'BlockException' handler, there are three options:

1. Global exception handling in spring MVC.

@ControllerAdvice
@Order(0)
public class SentinelSpringMvcBlockHandlerConfig {
    private Logger logger = LoggerFactory.getLogger(this.getClass());
    @ExceptionHandler(BlockException.class)
    @ResponseBody
    public String sentinelBlockHandler(BlockException e) {
        AbstractRule rule = e.getRule();
        logger.info("Blocked by sentinel, {}", rule.toString());
        return "Blocked by Sentinel";
    }
}

2. Use DefaultBlockExceptionHandler

//SentinelWebMvcTotalConfig config = new SentinelWebMvcTotalConfig();
SentinelWebMvcConfig config = new SentinelWebMvcConfig();
config.setBlockExceptionHandler(new DefaultBlockExceptionHandler());

3. implements BlockExceptionHandler

//SentinelWebMvcTotalConfig config = new SentinelWebMvcTotalConfig();
SentinelWebMvcConfig config = new SentinelWebMvcConfig();
config.setBlockExceptionHandler((request, response, e) -> {
    String resourceName = e.getRule().getResource();
    //Depending on your situation, you can choose to process or throw
    if ("/hello".equals(resourceName)) {
        //Do something ......
        //Write string or error page;
        response.getWriter().write("Blocked by sentinel");
    } else {
        //Handle it in global exception handling
        throw e;
    }
});

Configuration

• Common configuration in SentinelWebMvcConfig and SentinelWebMvcTotalConfig

name	description	type	default value
blockExceptionHandler	The handler when blocked by sentinel, there are three options: 1. The default value is null, you can hanlde BlockException in spring MVC; 2.Use DefaultBlockExceptionHandler; 3. implements BlockExceptionHandler	BlockExceptionHandler	null
originParser	RequestOriginParser interface is useful for extracting request origin (e.g. IP or appName from HTTP Header) from HTTP request	RequestOriginParser	null

• SentinelWebMvcConfig configuration

name	description	type	default value
urlCleaner	The UrlCleaner interface is designed for clean and unify the URL resource. For REST APIs, you can to clean the URL resource (e.g. /api/user/getById and /api/user/getByName -> /api/user/getBy*), avoid the amount of context and will exceed the threshold	UrlCleaner	null
requestAttributeName	Attribute name in request used by sentinel, please check record log, if it is already used, please set	String	sentinel_spring_mvc_entry_container
httpMethodSpecify	Specify http method, for example: GET:/hello	boolean	false

SentinelWebMvcTotalConfig configuration

name	description	type	default value
totalResourceName	The resource name in SentinelTotalInterceptor	String	spring-mvc-total-url-request
requestAttributeName	Attribute name in request used by sentinel, please check record log, if it is already used, please set	String	sentinel_spring_mvc_total_entry_container