feat: "max_concurrent_connections"

Author: mirkobrombin

internal/config/config.go

@@ -35,9 +35,10 @@ type SiteConfig struct {
 	ReadHeaderTimeout int               `json:"read_header_timeout"` // in seconds
 	IdleTimeout       int               `json:"idle_timeout"`        // in seconds
 	MaxHeaderBytes    int               `json:"max_header_bytes"`    // in bytes
-	FlushInterval     string            `json:"proxy_flush_interval"`
-	BufferSizeKB      int               `json:"buffer_size_kb"`
-	EnableLogging     *bool             `json:"enable_logging,omitempty"` // Default true if nil
+	FlushInterval            string                 `json:"proxy_flush_interval"`
+	BufferSizeKB             int                    `json:"buffer_size_kb"`
+	MaxConcurrentConnections int                    `json:"max_concurrent_connections"`
+	EnableLogging            *bool                  `json:"enable_logging,omitempty"` // Default true if nil
 
 	PluginConfigs map[string]interface{} `json:"plugin_configs"`
 }

internal/server/handler.go

@@ -60,6 +60,11 @@ func createHandler(conf config.SiteConfig, log *logger.Logger, identifier string
 		siteMwManager.Use(middleware.TimeoutMiddleware(timeout))
 	}
 
+	// Add Concurrency Middleware
+	if conf.MaxConcurrentConnections > 0 {
+		siteMwManager.Use(middleware.ConcurrencyMiddleware(conf.MaxConcurrentConnections))
+	}
+
 	// Add logging middleware last to ensure it wraps the entire request.
 	// We default to true if the pointer is nil.
 	if conf.EnableLogging == nil || *conf.EnableLogging {

internal/server/middleware/concurrency.go

@@ -0,0 +1,25 @@
+package middleware
+
+import (
+	"net/http"
+)
+
+// ConcurrencyMiddleware limits the number of concurrent requests.
+func ConcurrencyMiddleware(maxConcurrent int) MiddlewareFunc {
+	// Semaphore channel to limit concurrent access
+	sem := make(chan struct{}, maxConcurrent)
+
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			select {
+			case sem <- struct{}{}:
+				// Acquired token
+				defer func() { <-sem }() // Release token
+				next.ServeHTTP(w, r)
+			default:
+				// Limit reached
+				http.Error(w, "Service Unavailable (Max Concurrent Connections Reached)", http.StatusServiceUnavailable)
+			}
+		})
+	}
+}