feat: Add response logging and improve error handling in config proce…

…ssing

main.go

@@ -247,6 +247,13 @@ func (lm *LightyMux) newReverseProxy(nextHop *url.URL) *httputil.ReverseProxy {
 				lm.logger.Printf("Proxying request to: %s", req.URL.String())
 			}
 		},
+		ModifyResponse: func(resp *http.Response) error {
+			if lm.options.LogResponses {
+				lm.logger.Printf("Response from %s: status=%d, headers=%v",
+					resp.Request.URL.String(), resp.StatusCode, resp.Header)
+			}
+			return nil
+		},
 		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
 			if lm.options.LogErrors {
 				lm.logger.Printf("Proxy error: %v", err)
@@ -329,15 +336,13 @@ func (lm *LightyMux) applyConfig(config *LightyConfig) error {
 	for path, route := range config.Routes {
 		target := route.Target
 		if target == "" {
-			lm.logger.Printf("Skipping route %s: no target specified", path)
-			continue
+			return fmt.Errorf("route %s: no target specified", path)
 		}
 
 		if isWebScheme(target) {
 			nextHop, err := url.Parse(target)
 			if err != nil {
-				lm.logger.Printf("Error parsing URL %s: %v", target, err)
-				continue
+				return fmt.Errorf("route %s: invalid URL %s: %v", path, target, err)
 			}
 			proxy := lm.newReverseProxy(nextHop)
 
@@ -399,8 +404,7 @@ func (lm *LightyMux) applyConfig(config *LightyConfig) error {
 			// Check if target is a directory or a file
 			fileInfo, err := os.Stat(target)
 			if err != nil {
-				lm.logger.Printf("Error accessing path %s: %v", target, err)
-				continue
+				return fmt.Errorf("route %s: error accessing path %s: %v", path, target, err)
 			}
 
 			if fileInfo.IsDir() {

main_test.go

@@ -917,3 +917,81 @@ func TestRemoteReloaderErrors(t *testing.T) {
 		t.Error("Load() with non-existent server should return error")
 	}
 }
+
+func TestInitReloaderErrors(t *testing.T) {
+	tests := []struct {
+		name       string
+		configPath string
+		wantErr    string
+	}{
+		{
+			name:       "nonexistent config file",
+			configPath: "/nonexistent/config.yaml",
+			wantErr:    "failed to load initial config",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			lm := &LightyMux{
+				options: &Options{
+					ConfigRefreshInterval: time.Second,
+				},
+				mux:    http.NewServeMux(),
+				logger: log.New(os.Stderr, "", log.LstdFlags),
+			}
+			err := lm.initReloader(tt.configPath)
+			if err == nil {
+				t.Error("expected error, got nil")
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Errorf("expected error containing %q, got %v", tt.wantErr, err)
+			}
+		})
+	}
+}
+
+func TestProcessConfigErrors(t *testing.T) {
+	tests := []struct {
+		name     string
+		data     []byte
+		wantErr  string
+		setupLM  func(*LightyMux)
+	}{
+		{
+			name:    "invalid yaml",
+			data:    []byte(`invalid: yaml: [`),
+			wantErr: "failed to parse YAML",
+		},
+		{
+			name: "invalid URL target",
+			data: []byte(`
+routes:
+  "/api/":
+    target: "http://[invalid-url"  # Invalid URL syntax
+`),
+			wantErr: "failed to apply config",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buf := &strings.Builder{}
+			lm := &LightyMux{
+				options: &Options{},
+				mux:     http.NewServeMux(),
+				logger:  log.New(buf, "", log.LstdFlags),
+			}
+			if tt.setupLM != nil {
+				tt.setupLM(lm)
+			}
+			err := lm.processConfig(tt.data)
+			if err == nil {
+				t.Error("expected error, got nil")
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Errorf("expected error containing %q, got %v", tt.wantErr, err)
+			}
+		})
+	}
+}