fixed middleware implementation, added middleware tracing for easier debug

internal/api/v1/health_check.go

@@ -0,0 +1,34 @@
+package v1
+
+import (
+	"net"
+	"net/http"
+
+	U "github.com/yusing/go-proxy/internal/api/v1/utils"
+	"github.com/yusing/go-proxy/internal/common"
+)
+
+func IsSiteHealthy(url string) bool {
+	// try HEAD first
+	// if HEAD is not allowed, try GET
+	resp, err := U.Head(url)
+	if resp != nil {
+		resp.Body.Close()
+	}
+	if err != nil && resp != nil && resp.StatusCode == http.StatusMethodNotAllowed {
+		_, err = U.Get(url)
+	}
+	if resp != nil {
+		resp.Body.Close()
+	}
+	return err == nil
+}
+
+func IsStreamHealthy(scheme, address string) bool {
+	conn, err := net.DialTimeout(scheme, address, common.DialTimeout)
+	if err != nil {
+		return false
+	}
+	conn.Close()
+	return true
+}