1、什麼是動态路由，也就是在網關服務不停機的狀态下，動态的添加route或者删除route，這就是動态路由的定義，我們在前面實戰zuul的時候也提到過這個問題，當時的實作動态路由的方式是，使用配置中心進行route的配置，然後在增删路由的時候，使用actuator進行手動重新整理。 當然在 spring-cloud-gateway中也可以這樣實作，但是 spring-cloud-gateway中還為我們提供了另一種方式，那就是直接使用actuator API，官網位址如下：https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/#actuator-api。
2、使用 spring-cloud-gateway 的 actuator API來實作動态路由實戰：
2.1、在項目中引入spring-boot-starter-actuator的依賴：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
2.2、暴露端點：
management:
endpoints:
web:
exposure:
include: "*"
2.3、使用 spring-cloud-gateway 的 actuator API來檢視已經配置的路由資訊，位址為 http://網關服務ip:網關服務位址/actuator/gateway/routes 可得出已經配置的路由清單：
[
{
"predicate": "Paths: [/gateway-server/**], match trailing slash: true",
"metadata": {
"jmx.port": "62460",
"management.port": "6060"
},
"route_id": "ReactiveCompositeDiscoveryClient_GATEWAY-SERVER",
"filters": [
"[[RewritePath /gateway-server/(?<remaining>.*) = '/${remaining}'], order = 1]"
],
"uri": "lb://GATEWAY-SERVER",
"order": 0
},
{
"predicate": "Paths: [/orderapi/**], match trailing slash: true",
"route_id": "orderapi",
"filters": [
"[[StripPrefix parts = 1], order = 1]",
"[[Hystrix name = 'fallbackcmd', fallback = forward:/orderapi/order/mock], order = 2]",
"[org.springframework.cloud.gateway.filter.factory.RequestRateLimiterGatewayFilterFactory$$Lambda$878/[email protected], order = 3]"
],
"uri": "http://localhost:7070",
"order": 0
},
{
"predicate": "Paths: [/userapi/**], match trailing slash: true",
"route_id": "userapi",
"filters": [
"[[StripPrefix parts = 1], order = 1]"
],
"uri": "lb://user-service",
"order": 0
},
{
"predicate": "(Paths: [/customer/predicate/**], match trailing slash: true && [email protected])",
"route_id": "costomer_predicate",
"filters": [
"[[StripPrefix parts = 2], order = 1]"
],
"uri": "http://www.baidu.com:80",
"order": 0
}
]
2.4、使用 spring-cloud-gateway 的 actuator API來添加路由：
請求位址：http://localhost:6060/actuator/gateway/routes/api_route
請求方式：post application/json
入參格式：
{
"id": "first_route",
"predicates": [{
"name": "Path",
"args": {
"_genkey_0": "/api1"
}
}],
"filters": [{
"name": "StripPrefix",
"args": {
"_genkey_0": 1
}
}],
"uri": "https://www.baidu.com",
"order": 0
}
添加完成後再次檢視路由清單，如下：
[
{
"predicate": "Paths: [/gateway-server/**], match trailing slash: true",
"metadata": {
"jmx.port": "62818",
"management.port": "6060"
},
"route_id": "ReactiveCompositeDiscoveryClient_GATEWAY-SERVER",
"filters": [
"[[RewritePath /gateway-server/(?<remaining>.*) = '/${remaining}'], order = 1]"
],
"uri": "lb://GATEWAY-SERVER",
"order": 0
},
{
"predicate": "Paths: [/orderapi/**], match trailing slash: true",
"route_id": "orderapi",
"filters": [
"[[StripPrefix parts = 1], order = 1]",
"[[Hystrix name = 'fallbackcmd', fallback = forward:http://localhost:6060/fallback], order = 2]",
"[org.springframework.cloud.gateway.filter.factory.RequestRateLimiterGatewayFilterFactory$$Lambda$878/[email protected], order = 3]"
],
"uri": "http://localhost:7070",
"order": 0
},
{
"predicate": "Paths: [/userapi/**], match trailing slash: true",
"route_id": "userapi",
"filters": [
"[[StripPrefix parts = 1], order = 1]"
],
"uri": "lb://user-service",
"order": 0
},
{
"predicate": "(Paths: [/customer/predicate/**], match trailing slash: true && [email protected])",
"route_id": "costomer_predicate",
"filters": [
"[[StripPrefix parts = 2], order = 1]"
],
"uri": "http://www.baidu.com:80",
"order": 0
},
{
"predicate": "Paths: [/api1], match trailing slash: true",
"route_id": "api_route",
"filters": [
"[[StripPrefix parts = 1], order = 1]"
],
"uri": "https://www.baidu.com:443",
"order": 0
}
]
可見我們添加的路由api_route已經添加進去了，其他的删除的接口也都有。
3、spring-cloud-gateway 的 actuator API來實作動态route的擴充：
上面我們講解了使用 actuator API來實作動态路由的實戰，接下來我們來針對這種方式進行擴充，為什麼要擴充呢？原因就是actuator API來實作動态路的方式，在預設情況下是沒有之持久化的,也就是說一旦重新開機網關服務的話，動态添加的路由就沒有了，是以我們需要進行擴充。
我們就實作使用redis來儲存路由資訊吧，實作方式如下，在spring-cloud-gateway中提供了一個接口 RouteDefinitionRepository 路由定義倉庫，類圖如下：
預設值提供了存在在記憶體中的倉庫。
接下來我們來實作存儲在redis中的實作類：
@Component
public class RedisRouteDefRepository implements RouteDefinitionRepository {
public static final String GATEWAY_ROUTE_REDIS_KEY = "gateway_route_redis_key";
@Autowired
private StringRedisTemplate redisTemplate;
@Override
public Flux<RouteDefinition> getRouteDefinitions() {
List<RouteDefinition> list = new ArrayList <>();
redisTemplate.opsForHash().values(GATEWAY_ROUTE_REDIS_KEY).stream().forEach(route->{
list.add(JSON.parseObject(route.toString(), RouteDefinition.class));
});
return Flux.fromIterable(list);
}
@Override
public Mono<Void> save(Mono <RouteDefinition> route) {
return route.flatMap(routeDefinition ->{
redisTemplate.opsForHash().put(GATEWAY_ROUTE_REDIS_KEY, routeDefinition.getId(), JSON.toJSONString(routeDefinition));
return Mono.empty();
});
}
@Override
public Mono <Void> delete(Mono <String> routeId) {
return routeId.flatMap(id->{
redisTemplate.opsForHash().delete(GATEWAY_ROUTE_REDIS_KEY, id);
return Mono.empty();
});
}
}
這樣動态添加的路由資訊就會被儲存在redis中，而在配置檔案中定義的路由資訊是不會儲存在redis中的：
