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 getRouteDefinitions() {
List 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 save(Mono route) {
return route.flatMap(routeDefinition -> {
redisTemplate.opsForHash().put(GATEWAY_ROUTES, routeDefinition.getId(), JSONObject.toJSONString(routeDefinition));
return Mono.empty();
});
}
@Override
public Mono delete(Mono 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> 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> 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/actuato... , 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/(?.*)",
"replacement": "/${remaining}"
}
}
],
"uri": "lb://consul",
"order": 0
},
"order": 0
},
{
"route_id": "CompositeDiscoveryClient_idc-gateway",
"route_definition": {
"id": "CompositeDiscoveryClient_idc-gateway",
"predicates": [
{
"name": "Path",
"args": {
"pattern": "/idc-gateway/**"
}
}
],
"filters": [
{
"name": "RewritePath",
"args": {
"regexp": "/idc-gateway/(?.*)",
"replacement": "/${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/(?.*)",
"replacement": "/${remaining}"
}
}
],
"uri": "lb://idc-provider1",
"order": 0
},
"order": 0
},
{
"route_id": "CompositeDiscoveryClient_idc-provider2",
"route_definition": {
"id": "CompositeDiscoveryClient_idc-provider2",
"predicates": [
{
"name": "Path",
"args": {
"pattern": "/idc-provider2/**"
}
}
],
"filters": [
{
"name": "RewritePath",
"args": {
"regexp": "/idc-provider2/(?.*)",
"replacement": "/${remaining}"
}
}
],
"uri": "lb://idc-provider2",
"order": 0
},
"order": 0
}
] 这个时候访问 http://192.168.124.5:2000/idc... 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...
{
"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/actuato... , 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】。