224 lines
7.4 KiB
Go
224 lines
7.4 KiB
Go
package middleware
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import (
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"errors"
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"net/http"
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"net/http/httptest"
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"strings"
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"sync/atomic"
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"testing"
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"time"
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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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// newTestCircuitBreaker 构造与生产 CircuitBreaker 中间件相同语义、但可配置时序参数的版本，
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// 用于在测试中加速 CLOSED → OPEN → HALF_OPEN → CLOSED 状态机验证。
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func newTestCircuitBreaker(t *testing.T, interval, timeout time.Duration) (gin.HandlerFunc, *gobreaker.CircuitBreaker[struct{}]) {
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t.Helper()
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cb := gobreaker.NewCircuitBreaker[struct{}](gobreaker.Settings{
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Name: "test-svc",
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MaxRequests: 1,
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Interval: interval,
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Timeout: timeout,
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ReadyToTrip: func(counts gobreaker.Counts) bool {
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if counts.Requests == 0 {
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return false
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}
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return counts.TotalFailures*2 > counts.Requests
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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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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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if errors.Is(err, gobreaker.ErrOpenState) || errors.Is(err, gobreaker.ErrTooManyRequests) {
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c.AbortWithStatusJSON(http.StatusServiceUnavailable, gin.H{
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"error": "circuit_open",
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"retry_after": 30,
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})
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return
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}
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return
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}
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}, cb
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}
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func setupRouter(cbMW gin.HandlerFunc, downstreamStatus int) *gin.Engine {
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gin.SetMode(gin.TestMode)
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r := gin.New()
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r.Use(cbMW)
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r.GET("/test", func(c *gin.Context) {
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c.Status(downstreamStatus)
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})
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return r
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}
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// TestCircuitBreaker_ClosedToOpen 验证 5 秒窗口内错误率 > 50% 触发 CLOSED → OPEN。
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// ReadyToTrip 逻辑：TotalFailures*2 > Requests。
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// 第 1 次 5xx 后（Requests=1, Failures=1, 1*2>1）即触发；第 2 次请求被熔断直接返回 503。
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func TestCircuitBreaker_ClosedToOpen(t *testing.T) {
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mw, cb := newTestCircuitBreaker(t, time.Second, 30*time.Second)
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r := setupRouter(mw, http.StatusInternalServerError)
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// 第 1 次 5xx：放行到下游，触发 ReadyToTrip
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if w.Code != http.StatusInternalServerError {
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t.Fatalf("第 1 次请求期望 500，实际 %d", w.Code)
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}
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// 第 2 次请求应触发熔断：返回 503 + circuit_open
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w = httptest.NewRecorder()
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req = httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if w.Code != http.StatusServiceUnavailable {
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t.Fatalf("熔断后应返回 503，实际 %d", w.Code)
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}
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if !strings.Contains(w.Body.String(), "circuit_open") {
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t.Fatalf("响应体应包含 circuit_open，实际 %s", w.Body.String())
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}
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if cb.State() != gobreaker.StateOpen {
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t.Fatalf("CB 状态应为 OPEN，实际 %s", cb.State())
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}
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}
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// TestCircuitBreaker_OpenToHalfOpen 验证 OPEN 状态经过 Timeout 后转 HALF_OPEN，允许 1 个探测请求。
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// 注意：HALF_OPEN 状态只在探测请求执行期间可见；探测完成后（无论成功失败）状态会立刻转 CLOSED 或回 OPEN。
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// 因此本测试通过行为验证：OPEN 期间请求被拒（503），Timeout 后请求放行到下游（500）证明进入了 HALF_OPEN。
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func TestCircuitBreaker_OpenToHalfOpen(t *testing.T) {
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mw, cb := newTestCircuitBreaker(t, time.Second, 100*time.Millisecond)
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r := setupRouter(mw, http.StatusInternalServerError)
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// 触发熔断（1 次 5xx 即可）
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if cb.State() != gobreaker.StateOpen {
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t.Fatalf("预置条件失败：CB 应为 OPEN，实际 %s", cb.State())
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}
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// 立即再次请求：应被熔断拒绝（503）
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w = httptest.NewRecorder()
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req = httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if w.Code != http.StatusServiceUnavailable {
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t.Fatalf("OPEN 期间请求应被拒（503），实际 %d", w.Code)
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}
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// 等待 Timeout + 少量缓冲 → 状态转为 HALF_OPEN
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time.Sleep(150 * time.Millisecond)
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// 探测请求应放行到下游（返回 500，而非 503）
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// 证明状态已从 OPEN → HALF_OPEN（否则会返回 503）
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w = httptest.NewRecorder()
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req = httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if w.Code != http.StatusInternalServerError {
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t.Fatalf("HALF_OPEN 探测请求应放行到下游（500），实际 %d", w.Code)
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}
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// 探测失败（下游 500）→ 状态回 OPEN
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if cb.State() != gobreaker.StateOpen {
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t.Fatalf("探测失败后 CB 应回 OPEN，实际 %s", cb.State())
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}
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}
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// TestCircuitBreaker_HalfOpenToClosed 验证 HALF_OPEN 探测成功后转 CLOSED。
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func TestCircuitBreaker_HalfOpenToClosed(t *testing.T) {
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mw, cb := newTestCircuitBreaker(t, time.Second, 100*time.Millisecond)
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// 下游成功（200），让探测能成功
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r := setupRouter(mw, http.StatusOK)
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// 先用另一个 router 触发熔断（下游 500）
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badR := setupRouter(mw, http.StatusInternalServerError)
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for i := 0; i < 4; i++ {
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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badR.ServeHTTP(w, req)
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}
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if cb.State() != gobreaker.StateOpen {
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t.Fatalf("预置条件失败：CB 应为 OPEN，实际 %s", cb.State())
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}
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// 等待 Timeout → HALF_OPEN
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time.Sleep(150 * time.Millisecond)
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// 探测请求（下游 200）→ 成功 → 转 CLOSED
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if w.Code != http.StatusOK {
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t.Fatalf("探测请求应返回 200，实际 %d", w.Code)
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}
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if cb.State() != gobreaker.StateClosed {
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t.Fatalf("探测成功后 CB 应为 CLOSED，实际 %s", cb.State())
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}
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}
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// TestCircuitBreaker_HalfOpenToOpen 验证 HALF_OPEN 探测失败后转回 OPEN。
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func TestCircuitBreaker_HalfOpenToOpen(t *testing.T) {
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mw, cb := newTestCircuitBreaker(t, time.Second, 100*time.Millisecond)
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r := setupRouter(mw, http.StatusInternalServerError)
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// 触发熔断
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for i := 0; i < 4; i++ {
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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}
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if cb.State() != gobreaker.StateOpen {
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t.Fatalf("预置条件失败：CB 应为 OPEN，实际 %s", cb.State())
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}
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// 等待 Timeout → HALF_OPEN
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time.Sleep(150 * time.Millisecond)
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// 探测请求（下游 500）→ 失败 → 转 OPEN
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if cb.State() != gobreaker.StateOpen {
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t.Fatalf("探测失败后 CB 应重新转 OPEN，实际 %s", cb.State())
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}
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}
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// TestCircuitBreaker_4xxNotCounted 验证 4xx 响应不计入熔断失败计数。
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func TestCircuitBreaker_4xxNotCounted(t *testing.T) {
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var callCount int32
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mw, cb := newTestCircuitBreaker(t, time.Second, 30*time.Second)
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gin.SetMode(gin.TestMode)
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r := gin.New()
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r.Use(mw)
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r.GET("/test", func(c *gin.Context) {
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atomic.AddInt32(&callCount, 1)
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c.Status(http.StatusNotFound) // 404
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})
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// 触发 10 次 404，应不触发熔断
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for i := 0; i < 10; i++ {
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w := httptest.NewRecorder()
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req := httptest.NewRequest(http.MethodGet, "/test", nil)
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r.ServeHTTP(w, req)
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if w.Code != http.StatusNotFound {
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t.Fatalf("请求 %d 应返回 404，实际 %d", i+1, w.Code)
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}
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}
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if cb.State() != gobreaker.StateClosed {
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t.Fatalf("4xx 不应触发熔断，CB 应保持 CLOSED，实际 %s", cb.State())
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}
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// 所有请求应都到达下游（未被熔断短路）
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if got := atomic.LoadInt32(&callCount); got != 10 {
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t.Fatalf("下游应被调用 10 次，实际 %d", got)
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}
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}
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