spring cloud gateway 如何工做

spring cloud gateway的包結構(在Idea 2019.3中展現)

這個包是spring-cloud-gateway-core.這裏是真正的spring-gateway的實現的地方.
爲了證實,咱們打開spring-cloud-starter-gateway的pom文件

<dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gateway-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
    </dependencies>

除了cloud-start,starter-webflux就是cloud-gateway-core.因此後面咱們就分析
cloud-gateway-core這個jar包.

其中actuate中定義了GatewayControllerEndpoint,它提供了對外訪問的接口.

// TODO: Flush out routes without a definition
    @GetMapping("/routes")
    public Flux<Map<String, Object>> routes() {
        return this.routeLocator.getRoutes().map(this::serialize);
    }

    @GetMapping("/routes/{id}")
    public Mono<ResponseEntity<Map<String, Object>>> route(@PathVariable String id) {
        //......
    }
//如下方法是繼承於父類,抽象類AbstractGatewayControllerEndpoint
    @PostMapping("/refresh")
    public Mono<Void> refresh() {
        this.publisher.publishEvent(new RefreshRoutesEvent(this));
        return Mono.empty();
    }

    @GetMapping("/globalfilters")
    public Mono<HashMap<String, Object>> globalfilters() {
        return getNamesToOrders(this.globalFilters);
    }

    @GetMapping("/routefilters")
    public Mono<HashMap<String, Object>> routefilers() {
        return getNamesToOrders(this.GatewayFilters);
    }

    @GetMapping("/routepredicates")
    public Mono<HashMap<String, Object>> routepredicates() {
        return getNamesToOrders(this.routePredicates);
    }
    @PostMapping("/routes/{id}")
    @SuppressWarnings("unchecked")
    public Mono<ResponseEntity<Object>> save(@PathVariable String id,
            @RequestBody RouteDefinition route) {}
    @DeleteMapping("/routes/{id}")
    public Mono<ResponseEntity<Object>> delete(@PathVariable String id) {
        return this.routeDefinitionWriter.delete(Mono.just(id))
                .then(Mono.defer(() -> Mono.just(ResponseEntity.ok().build())))
                .onErrorResume(t -> t instanceof NotFoundException,
                        t -> Mono.just(ResponseEntity.notFound().build()));
    }

    @GetMapping("/routes/{id}/combinedfilters")
    public Mono<HashMap<String, Object>> combinedfilters(@PathVariable String id) {
        // TODO: missing global filters
    }

config包裏定義了一些Autoconfiguration和一些properties.讀取配置文件就在這裏完成.

咱們這裏看一下GatewayProperties.java

@ConfigurationProperties("spring.cloud.gateway")
@Validated
public class GatewayProperties {

    /**
     * List of Routes.
     */
    @NotNull
    @Valid
    private List<RouteDefinition> routes = new ArrayList<>();

    /**
     * List of filter definitions that are applied to every route.
     */
    private List<FilterDefinition> defaultFilters = new ArrayList<>();

    private List<MediaType> streamingMediaTypes = Arrays
            .asList(MediaType.TEXT_EVENT_STREAM, MediaType.APPLICATION_STREAM_JSON);
    #該類包括三個屬性,路由列表,默認過濾器列表和MediaType列表.路由列表中的路由定義RouteDefinition.
        過濾器中定義的FilterDefinition.

discovery定義了註冊中心的一些操做.
event定義了一系列事件,都繼承自ApplicationEvent.
filter定義了spring gateway實現的一些過濾器,包括gatewayfilter,globalfilter.