rename ngin to rest

rest/handler/breakerhandler.go

@@ -0,0 +1,41 @@
+package handler
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"zero/core/breaker"
+	"zero/core/logx"
+	"zero/core/stat"
+	"zero/rest/internal"
+	"zero/rest/internal/security"
+)
+
+const breakerSeparator = "://"
+
+func BreakerHandler(method, path string, metrics *stat.Metrics) func(http.Handler) http.Handler {
+	brk := breaker.NewBreaker(breaker.WithName(strings.Join([]string{method, path}, breakerSeparator)))
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			promise, err := brk.Allow()
+			if err != nil {
+				metrics.AddDrop()
+				logx.Errorf("[http] dropped, %s - %s - %s",
+					r.RequestURI, internal.GetRemoteAddr(r), r.UserAgent())
+				w.WriteHeader(http.StatusServiceUnavailable)
+				return
+			}
+
+			cw := &security.WithCodeResponseWriter{Writer: w}
+			defer func() {
+				if cw.Code < http.StatusInternalServerError {
+					promise.Accept()
+				} else {
+					promise.Reject(fmt.Sprintf("%d %s", cw.Code, http.StatusText(cw.Code)))
+				}
+			}()
+			next.ServeHTTP(cw, r)
+		})
+	}
+}