spring-cloud-gateway动态路由

概述

线上项目发布一般有以下几种方案:

  1. 停机发布
  2. 蓝绿部署
  3. 滚动部署
  4. 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。

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management:
endpoints:
web:
exposure:
include: "*"

2. redis配置

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@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

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@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

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@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

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@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。

  1. 访问 http://localhost:2000/actuator/gateway/routes , 可以看到只有默认路由。
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[
{
"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。

  1. 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

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{
"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

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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】。