Spring Cloud Gateway实现流量染色的示例代码

@Component
public class TrafficColoringFilter implements GlobalFilter, Ordered {
 
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        String userId = exchange.getRequest().getHeaders().getFirst("User-ID");
 
        if ("1001".equals(userId)) {
            ServerHttpRequest mutatedRequest = exchange.getRequest().mutate()
                .header("X-Traffic-Tag", "gray")
                .build();
            exchange = exchange.mutate().request(mutatedRequest).build();
        }
 
        return chain.filter(exchange);
    }
 
    @Override
    public int getOrder() {
        return -1; // 确保最早执行
    }
}

spring:
  cloud:
    gateway:
      routes:
        - id: gray-route
          uri: http://new-version-service
          predicates:
            - Header=X-Traffic-Tag, gray
        - id: default-route
          uri: http://old-version-service

@GetMapping("/api/test")
public String test(@RequestHeader(value = "X-Traffic-Tag", required = false) String tag) {
    log.info("当前流量标记为: {}", tag);
    return "Hello";
}