Spring Cloud Gateway（十三）：基于MongoDB实现动态路由

1、概述

Spring Cloud Gateway 默认的RouteDefinitionWriter实现类是org.springframework.cloud.gateway.route.InMemoryRouteDefinitionRepository，Route信息保存在当前实例的内存中，这在集群环境中会存在同步问题。本文就基于MongoD自定义一个RouteDefinitionWriter。

基本要点：

1、路由规则存储在MongoDB中（也可以是别的存储介质）

2、网关启动读取已配置好的路由规则

3、首次读取从MongoDB中加载，同时存在缓存中，以后读取直接从缓存读取

4、通过api动态添加路由规则，同时添加到缓存和MongoDB中

2、MongoRouteDefinition

import lombok.Data;
import org.springframework.cloud.gateway.filter.FilterDefinition;
import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
import org.springframework.data.mongodb.core.mapping.Field;

import java.util.ArrayList;
import java.util.List;

/**
 * 存储在mongodb中的自定义路由信息
 *
 * @author lkf
 * @date 2018-11-29 10-51
 */
@Data
public class MongoRouteDefinition {

    /**
     * 路由id
     */
    @Field(\"route_id\")
    private String routeId;
    /**
     * 路由谓词
     */
    private List<PredicateDefinition> predicates = new ArrayList<>();
    /**
     * 过滤器
     */
    private List<FilterDefinition> filters = new ArrayList<>();
    /**
     * 跳转地址uri
     */
    private String uri;
    /**
     * 路由顺序
     */
    private int order;

}

3、自定义RouteDefinitionRepository

package com.lkf.gateway.repository;

import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.data.mongodb.core.MongoTemplate;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.net.URI;
import java.util.*;

import static java.util.Collections.synchronizedMap;

/**
 * 使用Mongo保存自定义路由配置（代替默认的InMemoryRouteDefinitionRepository）
 * <p/>
 * 首次调用会把自定义路由配置信息加载到缓存中，以后的每次调用都从缓存返回
 *
 * @author lkf
 * @date 2018-11-29 10-48
 */
public class MongoRouteDefinitionRepository implements RouteDefinitionRepository {
    private final Map<String, RouteDefinition> routes = synchronizedMap(new LinkedHashMap<String, RouteDefinition>());

    private final MongoTemplate mongoTemplate;
    private final String mongoCollection;

    public MongoRouteDefinitionRepository(MongoTemplate mongoTemplate,String mongoCollection ) {
        this.mongoTemplate = mongoTemplate;
        this.mongoCollection = mongoCollection;
    }

    /**
     * 获取自定义路由信息
     *
     * @author lkf
     * @date 2018/11/29 12:00
     */
    @Override
    public Flux<RouteDefinition> getRouteDefinitions() {
        //判断本地缓存是否为空，不为空直接返回
        if (Objects.nonNull(routes) && routes.size() > 0) {
            return getRoutes();
        }
        //从mongodb获取自定义路由信息
        List<MongoRouteDefinition> mongoRouteDefinitionList = mongoTemplate.findAll(MongoRouteDefinition.class, mongoCollection);
        List<RouteDefinition> routeDefinitions = new ArrayList<>();
        //转换为路由定义对象并存入缓存中
        mongoRouteDefinitionList.forEach(mongoRouteDefinition -> {
            RouteDefinition routeDefinition = new RouteDefinition();
            routeDefinition.setId(mongoRouteDefinition.getRouteId());
            routeDefinition.setFilters(mongoRouteDefinition.getFilters());
            routeDefinition.setPredicates(mongoRouteDefinition.getPredicates());
            routeDefinition.setUri(URI.create(mongoRouteDefinition.getUri()));
            routeDefinition.setOrder(mongoRouteDefinition.getOrder());
            routes.put(routeDefinition.getId(), routeDefinition);
        });
        return Flux.fromIterable(routeDefinitions);
    }

    /**
     * 新增路由信息
     *
     * @param route 路由定义对象
     * @return reactor.core.publisher.Mono<java.lang.Void>
     * @author lkf
     * @date 2018/11/29 13:08
     */
    @Override
    public Mono<Void> save( Mono<RouteDefinition> route ) {
        return route.flatMap(routeDefinition -> {
            MongoRouteDefinition mongoRouteDefinition = new MongoRouteDefinition();
            mongoRouteDefinition.setRouteId(routeDefinition.getId());
            mongoRouteDefinition.setPredicates(routeDefinition.getPredicates());
            mongoRouteDefinition.setFilters(routeDefinition.getFilters());
            mongoRouteDefinition.setUri(routeDefinition.getUri().toString());
            mongoRouteDefinition.setOrder(routeDefinition.getOrder());
            mongoTemplate.save(mongoRouteDefinition, mongoCollection);
            routes.put(routeDefinition.getId(), routeDefinition);
            return Mono.empty();
        });

    }

    /**
     * 删除路由信息
     *
     * @param routeId 路由id
     * @return reactor.core.publisher.Mono<java.lang.Void>
     * @author lkf
     * @date 2018/11/29 13:09
     */
    @Override
    public Mono<Void> delete( Mono<String> routeId ) {
        return routeId.flatMap(id -> {
            if (routes.containsKey(id)) {
                routes.remove(id);
                return Mono.empty();
            }
            return Mono.defer(() -> Mono.error(new NotFoundException(\"RouteDefinition not found: \" + routeId)));
        });
    }

    private Flux<RouteDefinition> getRoutes() {
        return Flux.fromIterable(routes.values());
    }

}

4、自定义网关属性实体 CmpGatewayProperties

/**
 * 自定义网关属性实体
 *
 * @author lkf
 * @date 2018-11-29 13-13
 */
@Data
@ConfigurationProperties(prefix = \"cmp.gateway.route\")
public class CmpGatewayProperties {
    private String collection;
}

5、添加配置

## MongoDB 连接地址
spring.data.mongodb.uri=mongodb://账号:密码@ip:37017/库名
## 存放路由规则的 collection
cmp.gateway.route.collection=gateway_route

6、验证

6.1、MongoDB 添加路由规则

{
    \"_id\" : ObjectId(\"5bff4e9c12cc87ac0f888ddc\"),
    \"route_id\" : \"service-001\",
    \"predicates\" : [ 
        {
            \"name\" : \"Path\",
            \"args\" : {
                \"pattern\" : \"/user/**\"
            }
        }
    ],
    \"filters\" : [ 
        {
            \"name\" : \"RewritePath\",
            \"args\" : {
                \"regexp\" : \"/user-service/(?<remaining>.*)\",
                \"replacement\" : \"/${remaining}\"
            }
        }
    ],
    \"uri\" : \"lb://user-service\",
    \"order\" : 0
}

6.2、api 获取路由信息

通过网关暴露的api地址：

http://localhost:9000/actuator/gateway/routes

{
    \"route_id\": \"service-001\",
    \"route_definition\": {
        \"id\": \"service-001\",
        \"predicates\": [
            {
                \"name\": \"Path\",
                \"args\": {
                    \"pattern\": \"/user/**\"
                }
            }
        ],
        \"filters\": [
            {
                \"name\": \"RewritePath\",
                \"args\": {
                    \"regexp\": \"/user-service/(?<remaining>.*)\",
                    \"replacement\": \"/${remaining}\"
                }
            }
        ],
        \"uri\": \"lb://user-service\",
        \"order\": 0
    },
    \"order\": 0
}

6.3、api 新增路由信息

http://localhost:9000/actuator/gateway/routes/service-002

curl -H \"Content-Type:application/json\" -X POST --data \'{
    \"predicates\" : [ 
        {
            \"name\" : \"Path\",
            \"args\" : {
                \"pattern\" : \"/user/**\"
            }
        }
    ],
    \"filters\" : [ 
        {
            \"name\" : \"RewritePath\",
            \"args\" : {
                \"regexp\" : \"/user-service/(?<remaining>.*)\",
                \"replacement\" : \"/${remaining}\"
            }
        }
    ],
    \"uri\" : \"lb://user-service\",
    \"order\" : 0
}\' http://localhost:9000/actuator/gateway/routes/service-002

再次查询路由，结果如下，已经新增成功：