Implemented a real-time console log streaming via WebSocket for debugging purposes. Users can enable console output in settings to view application logs directly in the web interface.

pkg/web/console_logger.go

@@ -0,0 +1,105 @@
+// Fail2ban UI - A Swiss made, management interface for Fail2ban.
+//
+// Copyright (C) 2025 Swissmakers GmbH (https://swissmakers.ch)
+//
+// Licensed under the GNU General Public License, Version 3 (GPL-3.0)
+// You may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package web
+
+import (
+	"io"
+	"log"
+	"os"
+	"sync"
+
+	"github.com/swissmakers/fail2ban-ui/internal/config"
+)
+
+// ConsoleLogWriter is a multi-writer that writes to both the original log output
+// and broadcasts to WebSocket clients when console output is enabled
+type ConsoleLogWriter struct {
+	originalWriter io.Writer
+	hub            *Hub
+	mu             sync.RWMutex
+	enabled        bool
+}
+
+// NewConsoleLogWriter creates a new console log writer
+func NewConsoleLogWriter(hub *Hub, originalWriter io.Writer) *ConsoleLogWriter {
+	return &ConsoleLogWriter{
+		originalWriter: originalWriter,
+		hub:            hub,
+		enabled:        false,
+	}
+}
+
+// SetEnabled enables or disables console output broadcasting
+func (c *ConsoleLogWriter) SetEnabled(enabled bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.enabled = enabled
+}
+
+// Write implements io.Writer interface
+func (c *ConsoleLogWriter) Write(p []byte) (n int, err error) {
+	// Always write to original writer
+	n, err = c.originalWriter.Write(p)
+	
+	// Broadcast to WebSocket if enabled
+	c.mu.RLock()
+	enabled := c.enabled
+	c.mu.RUnlock()
+	
+	if enabled && c.hub != nil {
+		// Remove trailing newline for cleaner display
+		message := string(p)
+		if len(message) > 0 && message[len(message)-1] == '\n' {
+			message = message[:len(message)-1]
+		}
+		if len(message) > 0 {
+			c.hub.BroadcastConsoleLog(message)
+		}
+	}
+	
+	return n, err
+}
+
+var globalConsoleLogWriter *ConsoleLogWriter
+var consoleLogWriterOnce sync.Once
+
+// SetupConsoleLogWriter sets up the console log writer and replaces the standard log output
+// This captures all log.Printf, log.Println, etc. output
+func SetupConsoleLogWriter(hub *Hub) {
+	consoleLogWriterOnce.Do(func() {
+		// Create a multi-writer that writes to both original stdout and our console writer
+		globalConsoleLogWriter = NewConsoleLogWriter(hub, os.Stdout)
+		
+		// Replace log output - this captures all log.Printf, log.Println, etc.
+		log.SetOutput(globalConsoleLogWriter)
+	})
+}
+
+// UpdateConsoleLogEnabled updates the enabled state based on settings
+func UpdateConsoleLogEnabled() {
+	if globalConsoleLogWriter != nil {
+		settings := config.GetSettings()
+		globalConsoleLogWriter.SetEnabled(settings.ConsoleOutput)
+	}
+}
+
+// SetConsoleLogEnabled directly sets the enabled state
+func SetConsoleLogEnabled(enabled bool) {
+	if globalConsoleLogWriter != nil {
+		globalConsoleLogWriter.SetEnabled(enabled)
+	}
+}