Getting Started

Include Dependency
Add Enable Annotation To You Application
Choose-Plugin-Feature-To-Use
Specific Setting
- Enable Read Request Data
- The Grey Route
- Custom GlobalException Handler With Json
- Different Hystrix CommandKey For Each Route
- Use GatewayContext
- Dynamic Predicate With Existing Routes

1 . Include Dependency

Spring Cloud Gateway [Greenwich.SR1]

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>
    <!--If you need to use grey route,you should add next dependency ,but grey route only can be used with eureka discover-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Greenwich.SR1</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Gateway Plugin

<dependency>
    <groupId>pro.chenggang</groupId>
    <artifactId>spring-cloud-gateway-plugin</artifactId>
    <version>${version}</version>
</dependency>

Spring-Cloud-Gateway-Plugin Release Notes

2 . Add Enable Annotation To You Application

@EnableGatewayPlugin
public class SpringCloudGatewayPluginApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringCloudGatewayPluginApplication.class, args);
    }

}

Note: If You User SpringBoot 2.1.0+,You should set allow-bean-definition-overriding to true

spring:
  main:
    allow-bean-definition-overriding: true

3 . Choose Plugin Feature To Use

By default,the GatewayContext Filter is always into system

spring:
  profiles:
    active: dev
  cloud:
    gateway:
      plugin:
        config:
          log-request: true
          read-request-data: true # this setting will read all request data
          read-response-data: true
          exception-json-handler: true
        grey:
          enable: false
          grey-ribbon-rule: weight_response # assign grey ribbon rule

You Can Use GatewayContext To Get Cache JsonBody Or Form Body,Just Use

GatewayContext gatewayContext = exchange.getAttribute(GatewayContext.CACHE_GATEWAY_CONTEXT);

The Deference Between GreyRibbonRule.DEFAULT And GreyRibbonRule.WeightResponse

The Default GreyRibbonRule Just Use Round Rule As Base Ribbon Rule The WeightResponse GreyRibbonRule Use WeightResponse Rule As Base Ribbon Rule

4 . Specific Setting

1 . Enable Read Request Data

Specific Setting To Enable Read Request Data,This is helpful because : Read all request data will loss a lot of performance.It will reduce the gateway traffic.

spring:
  cloud:
    gateway:
      plugin:
        config:
          read-request-data-service-id-list:  #set specific serviceId from discover to read request Data
            - serviceId1
            - serviceId2
          read-request-data-path-list:        #set specific path to read request data
            - /service/path1/*
            - /service/path2/**
            - /service/path3

2 . The Grey Route

This feature only worked with eureka discover

Setup Gateway Properties

spring:
  cloud:
    gateway:
      plugin:
          grey:
            grey-rule-list:
              - service-id: privider1
                version: 2.0.0
                operation: OR
                rules:
                  - key: key1
                    value:
                      - value1
                      - value2
                      - value3
                  - key: key2
                    value:
                      - value4
                      - value5
                      - value6
              - service-id: provider2
                version: 2.0.0
                operation: AND
                rules:
                  - key: keya
                    value:
                      - value1a
                      - value2a
                      - value3a
                  - key: keyb
                    value:
                      - value4b
                      - value5b
                      - value6b

Set Up Service MetaInfo

#proiver1
eureka:
  instance:
    metadata-map:
      version: 2.0.0

The Properties Active Rule Principle

When Request URL Route To Provider1,When The Request JsonBody Or Form Data Contain The Key ->Key1 And Match Any Of The Value->[value1,value2,value3] The Route The Request To The Service Which Setup The MetaInfo With Specific Version Which Match The Gateway Grey Setup

3 . How To Custom GlobalException Handler With Json

In Order To Handle Other Exception,You Can Define Specific Bean Implements ExceptionHandlerStrategy By default,plugin supply DefaultExceptionHandlerStrategy In Case Of None Strategy Exist

@Slf4j
public class DefaultExceptionHandlerStrategy implements ExceptionHandlerStrategy {

    @Override
    public Class getHandleClass() {
        return Throwable.class;
    }

    @Override
    public ExceptionHandlerResult handleException(Throwable throwable) {
        ResponseResult<String> responseResult = new ResponseResult<>(SystemResponseInfo.GATEWAY_ERROR,throwable.getMessage());
        ExceptionHandlerResult result = new ExceptionHandlerResult(HttpStatus.INTERNAL_SERVER_ERROR, JSON.toJSONString(responseResult));
        log.debug("[DefaultExceptionHandlerStrategy]Handle Exception:{},Result:{}",throwable.getMessage(),result);
        log.error("[DefaultExceptionHandlerStrategy]Log Exception In Error Level,Exception Message:{}",throwable.getMessage());
        return result;
    }
}

Or You Can Use @ExceptionHandler just like below,

The@ResponseStatus is optional,if you don't add @ResponseStatus,the default HttpStatus is HttpStatus.INTERNAL_SERVER_ERROR

@Component
public class DemoExceptionHandler {

    @ExceptionHandler({NotFoundException.class})
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public Map handlerException(ServerWebExchange exchange,TimeoutException throwable){
        LinkedHashSet<URI> originalRequestUris = exchange.getAttributeOrDefault(ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR,null);
        Map map = Maps.newHashMapWithExpectedSize(2);
        map.put("URI",originalRequestUris);
        map.put("ExceptionMessage",throwable.getClass().getSimpleName());
        // return your custom object ,it will be serialize to json
        return map;
    }
  
    @ExceptionHandler({ClientException.class, TimeoutException.class})
    @ResponseStatus(HttpStatus.BAD_GATEWAY)
    public Map handlerException(ServerWebExchange exchange,TimeoutException throwable){
          LinkedHashSet<URI> originalRequestUris = exchange.getAttributeOrDefault(ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR,null);
          Map map = Maps.newHashMapWithExpectedSize(2);
          map.put("URI",originalRequestUris);
          map.put("ExceptionMessage",throwable.getClass().getSimpleName());
          // return your custom object ,it will be serialize to json
          return map;
    }
}

4 . How To Use different Hystrix CommandKey For Each Route

Include Hystrix Dependency

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

Just Change the HystrixGatewayFilterFactory to RouteHystrixGatewayFilterFactory

The Official reference about is HystrixGatewayFilterFactory HystrixGatewayFilterFactory

The properties setting just as below

spring.cloud.gateway.default-filters[0].name = RouteHystrix
spring.cloud.gateway.default-filters[0].args.name = fallbackcmd
spring.cloud.gateway.default-filters[0].args.fallbackUri = forward:/sys/fallback
hystrix.command.default.execution.isolation.strategy = SEMAPHORE
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds = 90000
hystrix.command.default.execution.isolation.semaphore.maxConcurrentRequests = 10000
hystrix.command.default.circuitBreaker.requestVolumeThreshold = 5000
hystrix.command.default.circuitBreaker.errorThresholdPercentage = 80

You should set hystrix.command.default to custom hystrix settings. The Command Key is config.name+":"+ routeId

5 . How To Use GatewayContext

You Can Use GatewayContext To Get Cache JsonBody Or Form Body,Just Use

GatewayContext gatewayContext = exchange.getAttribute(GatewayContext.CACHE_GATEWAY_CONTEXT);

The GatewayContext Contain below fields

@Getter
@Setter
@ToString
public class GatewayContext {

    public static final String CACHE_GATEWAY_CONTEXT = "cacheGatewayContext";
    /**
     * whether read request data
     */
    private Boolean readRequestData = false;
    /**
     * whether read response data
     */
    private Boolean readResponseData = false;
    /**
     * cache json body
     */
    private String requestBody;
    /**
     * cache Response Body
     */
    private Object responseBody;
    /**
     * request headers
     */
    private HttpHeaders requestHeaders;
    /**
     * cache form data
     */
    private MultiValueMap<String, String> formData;
    /**
     * cache all request data include:form data and query param
     */
    private MultiValueMap<String, String> allRequestData = new LinkedMultiValueMap<>(0);
}

6 . Dynamic Predicate With Existing Routes

Define A Component Implements DynamicRouteProcessor,this processor process serverWebExchange for dynamic route predicate

the DynamicRouteProcessor definition

/**
 * Process ServerWebExchange for dynamic route predicate
 * @author chenggang
 * @date 2019/07/17
 */
public interface DynamicRouteProcessor<T> {

    /**
     * preprocess action
     * @param exchange ServerWebExchange
     * @return process Result ,if result is Optional.empty(),then dynamic predicate not working
     */
    Optional<PreprocessResult<T>> preprocess(ServerWebExchange exchange);

    /**
     * process to unify config for predicate
     * @param preprocessResult pre process result
     * @param route current route
     * @return
     */
    Optional<DynamicRouteConfig> processConfig(PreprocessResult<T> preprocessResult, Route route);

    /**
     * target predicate bean 's class
     * @return RoutePredicateFactory Class
     */
    Optional<Class< ? extends AbstractRoutePredicateFactory>> targetPredicateBeanClass();
}

custom dynamic route processor

@Component
public class CustomDynamicRouteProcessor implements DynamicRouteProcessor {

    @Override
    public Optional<PreprocessResult> preprocess(ServerWebExchange exchange) {
        String route = exchange.getRequest().getHeaders().getFirst("route");
        if(StringUtils.isBlank(route)){
            return Optional.of(PreprocessResult.builder().result(false).build());
        }
        return Optional.of(PreprocessResult.builder().result(true).resultData(route).build());
    }

    @Override
    public Optional<DynamicRouteConfig> processConfig(PreprocessResult preprocessResult, Route route) {
        if(!preprocessResult.getResult()){
            return Optional.empty();
        }
        Object resultData = preprocessResult.getResultData();
        if(!(resultData instanceof String)){
            return Optional.empty();
        }
        String data = (String) resultData;
        DemoDynamicRoutePredicateFactory.Config config = DemoDynamicRoutePredicateFactory.Config.builder().header(data).route(route).build();
        return Optional.of(config);
    }

    @Override
    public Optional<Class<? extends AbstractRoutePredicateFactory>> targetPredicateBeanClass() {
        return Optional.of(DemoDynamicRoutePredicateFactory.class);
    }
}

Define a AbstractRoutePredicateFactory ,the Config Class Must Implements DynamicRouteConfig

@Slf4j
@Component
public class DemoDynamicRoutePredicateFactory extends AbstractRoutePredicateFactory<DemoDynamicRoutePredicateFactory.Config> {

    public DemoDynamicRoutePredicateFactory() {
        super(Config.class);
    }

    @Override
    public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            Route route = config.getRoute();
            if(Objects.isNull(route.getUri())){
                log.debug("Route Uri Is NUll Return False,RouteID:{}",route.getId());
                return false;
            }
            String routeUriHost = route.getUri().getHost();
            String headerData = config.getHeader();
            if(StringUtils.isBlank(routeUriHost) || StringUtils.isBlank(headerData)){
                log.debug("Route Uri Host Or HeaderData Is Blank Return False,RouteID:{}",route.getId());
                return false;
            }
            if(routeUriHost.equalsIgnoreCase(headerData)){
                log.debug("Route Uri Host Matched Header Data Return True,RouteID:{}",route.getId());
                route.getFilters();
                return true;
            }
            log.debug("Route Uri Not Matched Return False,RouteID:{}",route.getId());
            return false;
        };
    }

    @Getter
    @Setter
    @Builder
    @ToString
    @AllArgsConstructor
    public static class Config implements DynamicRouteConfig {

        private Route route;
        private String header;

    }
}

This Feature Support dynamic predicate with existing routes,Fox example: You can according the custom header to match the loadbalance route,

More logical detail to see DynamicRoutePredicateHandlerMapping

7 . Add ExtraData Into GatewayContext

a. Implement GatewayContextExtraData<T> With Your Own ExtraData

package pro.chenggang.plugin.springcloud.gateway.context;

public interface GatewayContextExtraData<T> {

    /**
     * get context extra data
     * @return
     */
    T getData();
}

b. Implement ContextExtraDataGenerator<T>，And Make It As a Spring Bean. This will used in Gatewaycontext Filter

package pro.chenggang.plugin.springcloud.gateway.context;

public interface ContextExtraDataGenerator<T> {

    /**
     * generate context extra data
     * @param serverWebExchange
     * @return
     */
    GatewayContextExtraData<T> generateContextExtraData(ServerWebExchange serverWebExchange);

}

@Bean
public ContextExtraDataGenerator contextExtraDataGenerator(){
    return new CustomeContextExtraDataGenerator();
}

c. Use GatewayContext To Get Your Own ExtraData

GatewayContext gatewayContext = exchange.getAttribute(GatewayContext.CACHE_GATEWAY_CONTEXT);
Object extraData = gatewayContext.getGatewayContextExtraData().getData();

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Getting Started

Getting Started

1 . Include Dependency

2 . Add Enable Annotation To You Application

3 . Choose Plugin Feature To Use

4 . Specific Setting

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