Spring Cloud Gateway 接口文档聚合实现

在微服务架构下，通常每个微服务都会使用Swagger来管理我们的接口文档，当微服务越来越多，接口查找管理无形中要浪费我们不少时间，毕竟懒是程序员的美德。

由于swagger2暂时不支持webflux 走了很多坑，完成这个效果感谢 @dreamlu @世言。

文档聚合效果

通过访问网关的 host:port/swagger-ui.html，即可实现: pig聚合文档效果预览传送门

通过右上角的Select a spec 选择服务模块来查看swagger文档

Pig的Zuul 核心实现

获取到zuul配置的路由信息，主要到SwaggerResource

1/**
2* 参考jhipster
3* GatewaySwaggerResourcesProvider
4*/
5@Component
6@Primary
7public class RegistrySwaggerResourcesProvider implements SwaggerResourcesProvider {
8    private final RouteLocator routeLocator;
9    public RegistrySwaggerResourcesProvider(RouteLocator routeLocator) {
10        this.routeLocator = routeLocator;
11    }
12    
13    @Override
14    public List<SwaggerResource> get() {
15        List<SwaggerResource> resources = new ArrayList<>();
16        List<Route> routes = routeLocator.getRoutes();
17        routes.forEach(route -> {
18            //授权不维护到swagger
19            if (!StringUtils.contains(route.getId(), ServiceNameConstant.AUTH_SERVICE)){
20                resources.add(swaggerResource(route.getId(), route.getFullPath().replace("**", "v2/api-docs")));
21            }
22        });
23        return resources;
24    }
25
26    private SwaggerResource swaggerResource(String name, String location) {
27        SwaggerResource swaggerResource = new SwaggerResource();
28        swaggerResource.setName(name);
29        swaggerResource.setLocation(location);
30        swaggerResource.setSwaggerVersion("2.0");
31        return swaggerResource;
32    }
33}

PigX的Spring Cloud Gateway 实现

注入路由到SwaggerResource

1@Component
2@Primary
3@AllArgsConstructor
4public class SwaggerProvider implements SwaggerResourcesProvider {
5	public static final String API_URI = "/v2/api-docs";
6	private final RouteLocator routeLocator;
7	private final GatewayProperties gatewayProperties;
8
9
10	@Override
11	public List<SwaggerResource> get() {
12		List<SwaggerResource> resources = new ArrayList<>();
13		List<String> routes = new ArrayList<>();
14		routeLocator.getRoutes().subscribe(route -> routes.add(route.getId()));
15		gatewayProperties.getRoutes().stream().filter(routeDefinition -> 	routes.contains(routeDefinition.getId()))
16			.forEach(routeDefinition -> routeDefinition.getPredicates().stream()
17				.filter(predicateDefinition -> "Path".equalsIgnoreCase(predicateDefinition.getName()))
18				.filter(predicateDefinition -> !"pigx-auth".equalsIgnoreCase(routeDefinition.getId()))
19				.forEach(predicateDefinition -> resources.add(swaggerResource(routeDefinition.getId(),
20					predicateDefinition.getArgs().get(NameUtils.GENERATED_NAME_PREFIX + "0")
21						.replace("/**", API_URI)))));
22		return resources;
23	}
24
25	private SwaggerResource swaggerResource(String name, String location) {
26		SwaggerResource swaggerResource = new SwaggerResource();
27		swaggerResource.setName(name);
28		swaggerResource.setLocation(location);
29		swaggerResource.setSwaggerVersion("2.0");
30		return swaggerResource;
31	}
32}
33

提供swagger 对外接口配置

1@Slf4j
2@Configuration
3@AllArgsConstructor
4public class RouterFunctionConfiguration {
5	private final SwaggerResourceHandler swaggerResourceHandler;
6	private final SwaggerSecurityHandler swaggerSecurityHandler;
7	private final SwaggerUiHandler swaggerUiHandler;
8
9	@Bean
10	public RouterFunction routerFunction() {
11		return RouterFunctions.route(
12			.andRoute(RequestPredicates.GET("/swagger-resources")
13				.and(RequestPredicates.accept(MediaType.ALL)), swaggerResourceHandler)
14			.andRoute(RequestPredicates.GET("/swagger-resources/configuration/ui")
15				.and(RequestPredicates.accept(MediaType.ALL)), swaggerUiHandler)
16			.andRoute(RequestPredicates.GET("/swagger-resources/configuration/security")
17				.and(RequestPredicates.accept(MediaType.ALL)), swaggerSecurityHandler);
18
19	}
20}

业务handler 的实现

1	@Override
2	public Mono<ServerResponse> handle(ServerRequest request) {
3		return ServerResponse.status(HttpStatus.OK)
4			.contentType(MediaType.APPLICATION_JSON_UTF8)
5			.body(BodyInserters.fromObject(swaggerResources.get()));
6	}
7	
8    @Override
9	public Mono<ServerResponse> handle(ServerRequest request) {
10		return ServerResponse.status(HttpStatus.OK)
11			.contentType(MediaType.APPLICATION_JSON_UTF8)
12			.body(BodyInserters.fromObject(
13				Optional.ofNullable(securityConfiguration)
14					.orElse(SecurityConfigurationBuilder.builder().build())));
15	}
16	
17    @Override
18    public Mono<ServerResponse> handle(ServerRequest request) {
19        return ServerResponse.status(HttpStatus.OK)
20			.contentType(MediaType.APPLICATION_JSON_UTF8)
21			.body(BodyInserters.fromObject(
22				Optional.ofNullable(uiConfiguration)
23					.orElse(UiConfigurationBuilder.builder().build())));
24	}

swagger路径转换

通过以上配置，可以实现文档的参考和展示了，但是使用swagger 的 try it out 功能发现路径是路由切割后的路径比如：

swagger 文档中的路径为：主机名：端口：映射路径少了一个 服务路由前缀，是因为展示handler 经过了 StripPrefixGatewayFilterFactory 这个过滤器的处理，原有的路由前缀被过滤掉了！

方案1，通过swagger 的host 配置手动维护一个前缀

1return new Docket(DocumentationType.SWAGGER_2)
2    .apiInfo(apiInfo())
3    .host("主机名：端口：服务前缀")  //注意这里的主机名：端口是网关的地址和端口
4    .select()
5    .apis(RequestHandlerSelectors.withMethodAnnotation(ApiOperation.class))
6    .paths(PathSelectors.any())
7    .build()
8    .globalOperationParameters(parameterList);

方案2，增加X-Forwarded-Prefix

swagger 在拼装URL 数据时候，会增加X-Forwarder-Prefix 请求头里面的信息为前缀

通过如上分析，知道应该在哪里下手了吧，在网关上追加一个请求头即可

1@Component
2public class SwaggerHeaderFilter extends AbstractGatewayFilterFactory {
3	private static final String HEADER_NAME = "X-Forwarded-Prefix";
4
5	@Override
6	public GatewayFilter apply(Object config) {
7		return (exchange, chain) -> {
8			ServerHttpRequest request = exchange.getRequest();
9			String path = request.getURI().getPath();
10			if (!StringUtils.endsWithIgnoreCase(path, SwaggerProvider.API_URI)) {
11				return chain.filter(exchange);
12			}
13
14			String basePath = path.substring(0, path.lastIndexOf(SwaggerProvider.API_URI));
15
16
17			ServerHttpRequest newRequest = request.mutate().header(HEADER_NAME, basePath).build();
18			ServerWebExchange newExchange = exchange.mutate().request(newRequest).build();
19			return chain.filter(newExchange);
20		};
21	}
22}

总结

相对zuul的实现，核心逻辑都是一样，获取到配置路由信息，重写swaggerresource
gateway的配置稍微麻烦，资源的提供handler，swagger url 重写的细节
源码获取：最新Spring Cloud 技术栈，基于Spring Cloud Finchley.RELEASE、oAuth2 实现的权限系统