chore: version 1.0.7 - add log levels

- Add configurable log levels: DEBUG, INFO, WARN, ERROR
- Replace debug.enabled with log.level in configuration
- Add Warn/Warnf methods for warning messages
- Log orphan events and buffer overflow as WARN
- Log parse errors as WARN
- Log raw events and correlations as DEBUG

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

internal/config/config_test.go

@@ -474,3 +474,83 @@ func TestGetSocketPermissions(t *testing.T) {
 		})
 	}
 }
+
+func TestLogConfig_GetLevel(t *testing.T) {
+	tests := []struct {
+		name     string
+		config   LogConfig
+		expected string
+	}{
+		{
+			name:     "default",
+			config:   LogConfig{Level: ""},
+			expected: "INFO",
+		},
+		{
+			name:     "DEBUG uppercase",
+			config:   LogConfig{Level: "DEBUG"},
+			expected: "DEBUG",
+		},
+		{
+			name:     "debug lowercase",
+			config:   LogConfig{Level: "debug"},
+			expected: "DEBUG",
+		},
+		{
+			name:     "WARN",
+			config:   LogConfig{Level: "WARN"},
+			expected: "WARN",
+		},
+		{
+			name:     "ERROR",
+			config:   LogConfig{Level: "ERROR"},
+			expected: "ERROR",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.config.GetLevel()
+			if result != tt.expected {
+				t.Errorf("GetLevel() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestLoad_LogLevel(t *testing.T) {
+	content := `
+log:
+  level: DEBUG
+
+inputs:
+  unix_sockets:
+    - name: http
+      path: /var/run/logcorrelator/http.socket
+    - name: network
+      path: /var/run/logcorrelator/network.socket
+
+outputs:
+  file:
+    path: /var/log/test.log
+
+correlation:
+  time_window_s: 1
+  emit_orphans: true
+`
+
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, "config.yml")
+	if err := os.WriteFile(configPath, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write config: %v", err)
+	}
+
+	cfg, err := Load(configPath)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if cfg.Log.GetLevel() != "DEBUG" {
+		t.Errorf("expected log level DEBUG, got %s", cfg.Log.GetLevel())
+	}
+}