spring-cloud-gateway动态路由
- 2020 年 4 月 4 日
- 筆記
概述
线上项目发布一般有以下几种方案:
- 停机发布
- 蓝绿部署
- 滚动部署
- 灰度发布
停机发布 这种发布一般在夜里或者进行大版本升级的时候发布，因为需要停机，所以现在大家都在研究 Devops 方案。
蓝绿部署 需要准备两个相同的环境。一个环境新版本，一个环境旧版本，通过负载均衡进行切换与回滚，目的是为了减少服务停止时间。
滚动部署 就是在升级过程中，并不一下子启动所有新版本，是先启动一台新版本，再停止一台老版本，然后再启动一台新版本，再停止一台老版本，直到升级完成。基于 k8s 的升级方案默认就是滚动部署。
灰度发布 也叫金丝雀发布，灰度发布中，常常按照用户设置路由权重，例如 90%的用户维持使用老版本，10%的用户尝鲜新版本。不同版本应用共存，经常与 A/B 测试一起使用，用于测试选择多种方案。
上边介绍的几种发布方案，主要是引出我们接下来介绍的 spring-cloud-gateway 动态路由，我们可以基于动态路由、负载均衡和策略加载去实现 灰度发布。当然现在有很多开源的框架可以实现 灰度发布，这里只是研究学习。
动态路由
spring-cloud-gateway 默认将路由加载在内存中。具体可以参见 InMemoryRouteDefinitionRepository 类的实现。
这里我们基于 Redis 实现动态路由。基础项目见 spring-cloud-gateway 简介
1. 将 actuator 的端点暴露出来。
management: endpoints: web: exposure: include: "*" 2. redis 配置
@Configuration public class RedisConfig { @Bean(name = {"redisTemplate", "stringRedisTemplate"}) public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory factory) { StringRedisTemplate redisTemplate = new StringRedisTemplate(); redisTemplate.setConnectionFactory(factory); return redisTemplate; } } 3. 将原内存路由持久化到 redis
@Component public class RedisRouteDefinitionRepository implements RouteDefinitionRepository { /** * hash存储的key */ public static final String GATEWAY_ROUTES = "gateway_dynamic_route"; @Resource private StringRedisTemplate redisTemplate; /** * 获取路由信息 * @return */ @Override public Flux<RouteDefinition> getRouteDefinitions() { List<RouteDefinition> routeDefinitions = new ArrayList<>(); redisTemplate.opsForHash().values(GATEWAY_ROUTES).stream() .forEach(routeDefinition -> routeDefinitions.add(JSON.parseObject(routeDefinition.toString(), RouteDefinition.class))); return Flux.fromIterable(routeDefinitions); } @Override public Mono<Void> save(Mono<RouteDefinition> route) { return route.flatMap(routeDefinition -> { redisTemplate.opsForHash().put(GATEWAY_ROUTES, routeDefinition.getId(), JSONObject.toJSONString(routeDefinition)); return Mono.empty(); }); } @Override public Mono<Void> delete(Mono<String> routeId) { return routeId.flatMap(id -> { if (redisTemplate.opsForHash().hasKey(GATEWAY_ROUTES, id)) { redisTemplate.opsForHash().delete(GATEWAY_ROUTES, id); return Mono.empty(); } return Mono.defer(() -> Mono.error(new NotFoundException("route definition is not found, routeId:" + routeId))); }); } } 4. 重写动态路由服务
@Service public class GatewayDynamicRouteService implements ApplicationEventPublisherAware { @Resource private RedisRouteDefinitionRepository redisRouteDefinitionRepository; private ApplicationEventPublisher applicationEventPublisher; /** * 增加路由 * @param routeDefinition * @return */ public int add(RouteDefinition routeDefinition) { redisRouteDefinitionRepository.save(Mono.just(routeDefinition)).subscribe(); applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this)); return 1; } /** * 更新 * @param routeDefinition * @return */ public int update(RouteDefinition routeDefinition) { redisRouteDefinitionRepository.delete(Mono.just(routeDefinition.getId())); redisRouteDefinitionRepository.save(Mono.just(routeDefinition)).subscribe(); applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this)); return 1; } /** * 删除 * @param id * @return */ public Mono<ResponseEntity<Object>> delete(String id) { return redisRouteDefinitionRepository.delete(Mono.just(id)).then(Mono.defer(() -> Mono.just(ResponseEntity.ok().build()))) .onErrorResume(t -> t instanceof NotFoundException, t -> Mono.just(ResponseEntity.notFound().build())); } @Override public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) { this.applicationEventPublisher = applicationEventPublisher; } } 5. 对外暴露接口
@RestController @RequestMapping("/gateway") public class GatewayDynamicRouteController { @Resource private GatewayDynamicRouteService gatewayDynamicRouteService; @PostMapping("/add") public String create(@RequestBody RouteDefinition entity) { int result = gatewayDynamicRouteService.add(entity); return String.valueOf(result); } @PostMapping("/update") public String update(@RequestBody RouteDefinition entity) { int result = gatewayDynamicRouteService.update(entity); return String.valueOf(result); } @DeleteMapping("/delete/{id}") public Mono<ResponseEntity<Object>> delete(@PathVariable String id) { return gatewayDynamicRouteService.delete(id); } } 测试
测试前删除我们配置的静态路由，因为静态路由和 redis 动态路由同时存在时取并集。
- 访问 http://localhost:2000/actuator/gateway/routes , 可以看到只有默认路由。
[ { "route_id": "CompositeDiscoveryClient_consul", "route_definition": { "id": "CompositeDiscoveryClient_consul", "predicates": [ { "name": "Path", "args": { "pattern": "/consul/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/consul/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://consul", "order": 0 }, "order": 0 }, { "route_id": "CompositeDiscoveryClient_idc-gateway", "route_definition": { "id": "CompositeDiscoveryClient_idc-gateway", "predicates": [ { "name": "Path", "args": { "pattern": "/idc-gateway/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/idc-gateway/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://idc-gateway", "order": 0 }, "order": 0 }, { "route_id": "CompositeDiscoveryClient_idc-provider1", "route_definition": { "id": "CompositeDiscoveryClient_idc-provider1", "predicates": [ { "name": "Path", "args": { "pattern": "/idc-provider1/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/idc-provider1/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://idc-provider1", "order": 0 }, "order": 0 }, { "route_id": "CompositeDiscoveryClient_idc-provider2", "route_definition": { "id": "CompositeDiscoveryClient_idc-provider2", "predicates": [ { "name": "Path", "args": { "pattern": "/idc-provider2/**" } } ], "filters": [ { "name": "RewritePath", "args": { "regexp": "/idc-provider2/(?<remaining>.*)", "replacement": "/${remaining}" } } ], "uri": "lb://idc-provider2", "order": 0 }, "order": 0 } ] 这个时候访问 http://192.168.124.5:2000/idc-provider1/provider1/1 根据结果可以推测能正确路由到 provider1， 测试结果一致。
- 创建
provider1路由，将路径设置为/p1/**，测试是否生效。
POST 请求 http://localhost:2000/gateway/add
{ "id":"provider1", "predicates":[ { "name":"Path", "args":{ "_genkey_0":"/p1/**" } }, { "name":"RemoteAddr", "args":{ "_genkey_0":"192.168.124.5/16" } } ], "filters":[ { "name":"StripPrefix", "args":{ "_genkey_0":"1" } } ], "uri":"lb://idc-provider1", "order":0 } 查看 redis 存储，或者请求 http://localhost:2000/actuator/gateway/routes , 都可以看到配置成功。
访问
curl http://localhost:2000/p1/provider1/1 结果输出 2001，与期望一致。
由此可见动态路由已经生效。
结语
本文到此结束。感兴趣的小伙伴后续可以通过加载配置文件，基于权重进行灰度。欢迎大家关注公众号【当我遇上你】。
