4307f6b73c
依据 coord-final-decisions §3.8 W1-W8 裁决与 president-final-rulings §2.15/§2.16/§2.19 完整实现网关硬化： - W1/W2: 错误码 GW_ 前缀 + ActionState 信封响应体 - W3: 全量替换为 log/slog 结构化日志 - W4: /readyz 并行 ping 9 下游 + 软失败规则 - W5: 7 个业务 Prometheus 指标 + /metrics 端点 - W6: tracer 资源属性补全（name/version/env/host） - W7: DevMode=true && ENV=production panic 防护 - W8: 保持共享 downstream 熔断 P2 RS256 升级：接入 shared-go/jwks.Fetcher（TTL 5min）。 P2.7+P3-P5 路由扩展：student/parent/messages/dashboard。 文档同步：README/01/02/known-issues，arch.db 已更新。 质量校验：go vet + build + test 均通过。
104 lines
2.5 KiB
Go
104 lines
2.5 KiB
Go
package middleware
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import (
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"net/http"
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"sync"
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"time"
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"github.com/edu-cloud/api-gateway/internal/observability"
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"github.com/gin-gonic/gin"
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)
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// bucket 是单个客户端的令牌桶
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type bucket struct {
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mu sync.Mutex
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tokens float64
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lastTime time.Time
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}
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// rateLimiter 持有所有客户端 IP 的令牌桶
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type rateLimiter struct {
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rps float64
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burst int
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buckets sync.Map // map[string]*bucket
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}
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// RateLimit 返回基于令牌桶的限流中间件（内存版，P6 迁 Redis）。
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// 每个客户端 IP 独立桶，按 rps（每秒令牌数）补充，最大容量为 burst。
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// 超限返回 429 + ActionState 信封（W1/W2 裁决）：
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//
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// {"success":false,"error":{"code":"GW_RATE_LIMITED","message":"..."},"retry_after":60}
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//
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// 内部启动 cleanup goroutine，每 5 分钟清理 10 分钟未访问的桶。
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func RateLimit(rps float64, burst int) gin.HandlerFunc {
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rl := &rateLimiter{rps: rps, burst: burst}
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// 启动清理 goroutine
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go rl.cleanup(5*time.Minute, 10*time.Minute)
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return func(c *gin.Context) {
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ip := c.ClientIP()
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b := rl.getBucket(ip)
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b.mu.Lock()
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now := time.Now()
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elapsed := now.Sub(b.lastTime).Seconds()
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b.lastTime = now
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// 按经过时间补充令牌
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b.tokens += elapsed * rl.rps
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if b.tokens > float64(rl.burst) {
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b.tokens = float64(rl.burst)
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}
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// 令牌不足：拒绝
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if b.tokens < 1 {
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b.mu.Unlock()
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observability.IncRateLimited(ip)
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c.Header("Retry-After", "60")
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c.AbortWithStatusJSON(http.StatusTooManyRequests, gin.H{
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"success": false,
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"error": gin.H{
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"code": "GW_RATE_LIMITED",
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"message": "rate limit exceeded",
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},
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"retry_after": 60,
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})
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return
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}
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b.tokens--
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b.mu.Unlock()
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c.Next()
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}
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}
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// getBucket 获取指定 IP 的令牌桶，不存在则新建（初始满桶）
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func (rl *rateLimiter) getBucket(ip string) *bucket {
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if v, ok := rl.buckets.Load(ip); ok {
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return v.(*bucket)
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}
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b := &bucket{
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tokens: float64(rl.burst),
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lastTime: time.Now(),
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}
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actual, _ := rl.buckets.LoadOrStore(ip, b)
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return actual.(*bucket)
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}
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// cleanup 周期性清理长时间未访问的桶，避免内存无限增长
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func (rl *rateLimiter) cleanup(interval, maxIdle time.Duration) {
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ticker := time.NewTicker(interval)
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defer ticker.Stop()
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for range ticker.C {
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now := time.Now()
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rl.buckets.Range(func(key, value any) bool {
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b := value.(*bucket)
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b.mu.Lock()
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idle := now.Sub(b.lastTime)
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b.mu.Unlock()
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if idle > maxIdle {
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rl.buckets.Delete(key)
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}
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return true
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})
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}
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}
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