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。
80 lines
2.4 KiB
Go
80 lines
2.4 KiB
Go
package middleware
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import (
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"errors"
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"log/slog"
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"net/http"
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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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"github.com/sony/gobreaker/v2"
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)
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// CircuitBreaker 返回针对指定服务的熔断中间件（W8 裁决：保持共享 downstream）。
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//
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// 基于 gobreaker v2 实现：
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// - Interval=5s：CLOSED 状态下的统计窗口
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// - ReadyToTrip：错误率 > 50% 触发 OPEN
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// - Timeout=30s：OPEN 持续 30 秒后转 HALF_OPEN
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// - MaxRequests=1：HALF_OPEN 仅允许 1 个探测请求
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//
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// 仅当下游返回 5xx 视为失败；4xx 与 2xx 不计入熔断。
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// 熔断打开或半开探测名额已满时返回 503 + ActionState 信封（W1/W2 裁决）：
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//
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// {"success":false,"error":{"code":"GW_CIRCUIT_OPEN","message":"..."},"retry_after":30}
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func CircuitBreaker(serviceName string) gin.HandlerFunc {
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cb := gobreaker.NewCircuitBreaker[struct{}](gobreaker.Settings{
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Name: serviceName,
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MaxRequests: 1,
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Interval: 5 * time.Second,
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Timeout: 30 * time.Second,
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ReadyToTrip: func(counts gobreaker.Counts) bool {
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// 请求数为 0 时不触发，避免除零
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if counts.Requests == 0 {
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return false
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}
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// 错误率 > 50%
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return counts.TotalFailures*2 > counts.Requests
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},
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OnStateChange: func(name string, from, to gobreaker.State) {
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observability.SetCircuitBreakerState(name, from.String(), 0)
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observability.SetCircuitBreakerState(name, to.String(), 1)
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slog.Info("circuit breaker state changed",
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"service", name,
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"from", from.String(),
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"to", to.String(),
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)
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},
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})
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return func(c *gin.Context) {
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_, err := cb.Execute(func() (struct{}, error) {
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c.Next()
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// 下游 5xx 视为熔断失败
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if c.Writer.Status() >= 500 {
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return struct{}{}, errors.New("downstream_error")
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}
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return struct{}{}, nil
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})
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if err != nil {
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// 熔断打开或半开探测名额已满：返回 503
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if errors.Is(err, gobreaker.ErrOpenState) || errors.Is(err, gobreaker.ErrTooManyRequests) {
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c.Header("Retry-After", "30")
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c.AbortWithStatusJSON(http.StatusServiceUnavailable, gin.H{
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"success": false,
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"error": gin.H{
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"code": "GW_CIRCUIT_OPEN",
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"message": "upstream circuit breaker open",
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},
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"retry_after": 30,
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})
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return
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}
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// 其他情况（下游已写 5xx 响应）：响应已写入，不覆盖
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return
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}
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}
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}
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