feat: add logging to Docker and iptables operations, fix iptables path

- Create /var/log/network-go directory in Dockerfile for log storage
- Add comprehensive logging to Docker client creation, network management, and container operations
- Add logging to iptables rule management (list, delete, etc.)
- Fix iptables executable path resolution in deleteMatchingLinesInContainer to use configured binary path

network-go/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"log"
 	"os"
 	"os/signal"
 	"syscall"
@@ -12,21 +11,24 @@ import (
 	"firewall_containers/network-go/docker"
 	"firewall_containers/network-go/firewall"
 	"firewall_containers/network-go/iptables"
+	"firewall_containers/network-go/logger"
 	"firewall_containers/network-go/watcher"
 )
 
 // Config path - can be overridden via environment variable
 const defaultConfigPath = "/etc/user/config/networks.json"
 
+// Log path - can be overridden via environment variable
+const defaultLogPath = "/var/log/network-go/network-go.log"
+
 // Watch period - can be overridden via environment variable
 const defaultWatchPeriod = 30 * time.Second
 
-func getConfigPath() string {
-	path := os.Getenv("NETWORKS_CONFIG_PATH")
-	if path == "" {
-		return defaultConfigPath
+func getEnv(key, defaultVal string) string {
+	if val := os.Getenv(key); val != "" {
+		return val
 	}
-	return path
+	return defaultVal
 }
 
 func getWatchPeriod() time.Duration {
@@ -36,7 +38,7 @@ func getWatchPeriod() time.Duration {
 	}
 	seconds, err := time.ParseDuration(periodStr + "s")
 	if err != nil {
-		log.Printf("MAIN: invalid WATCH_PERIOD_SECONDS=%s, using default %s", periodStr, defaultWatchPeriod)
+		logger.Warn("MAIN: invalid WATCH_PERIOD_SECONDS=%s, using default %s", periodStr, defaultWatchPeriod)
 		return defaultWatchPeriod
 	}
 	return seconds
@@ -47,34 +49,44 @@ func getDebug() bool {
 }
 
 func main() {
-	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
-	log.Println("MAIN: starting network-go firewall container manager")
-
-	configPath := getConfigPath()
+	configPath := getEnv("NETWORKS_CONFIG_PATH", defaultConfigPath)
+	logPath := getEnv("NETWORK_GO_LOG_PATH", defaultLogPath)
 	watchPeriod := getWatchPeriod()
 	debug := getDebug()
 
-	log.Printf("MAIN: config path = %s", configPath)
-	log.Printf("MAIN: watch period = %s", watchPeriod)
-	log.Printf("MAIN: debug = %v", debug)
+	// Initialize the dual-output logger (stdout + file)
+	log := logger.NewLogger(debug, logPath)
+	logger.SetDefault(log)
+
+	log.Info("MAIN: starting network-go firewall container manager")
+	log.Info("MAIN: config path = %s", configPath)
+	log.Info("MAIN: log path = %s", logPath)
+	log.Info("MAIN: watch period = %s", watchPeriod)
+	log.Info("MAIN: debug = %v", debug)
 
 	// Create Docker client (uses DOCKER_HOST env var automatically)
 	dockerClient, err := docker.NewClient()
 	if err != nil {
-		log.Fatalf("MAIN: failed to create Docker client: %v", err)
+		log.Error("MAIN: failed to create Docker client: %v", err)
+		os.Exit(1)
 	}
 	defer dockerClient.Close()
+	log.Info("MAIN: Docker client created")
 
 	// Create iptables manager
 	iptablesMgr := iptables.NewManager(debug)
+	log.Info("MAIN: iptables manager created (binary=%s)", iptablesMgr.Binary())
 
 	ctx := context.Background()
 
 	// Load initial config
 	cfg, err := config.Load(configPath)
 	if err != nil {
-		log.Fatalf("MAIN: failed to load initial config: %v", err)
+		log.Error("MAIN: failed to load initial config: %v", err)
+		os.Exit(1)
 	}
+	log.Info("MAIN: config loaded: %d networks, %d IPs, %d policies",
+		len(cfg.Networks), len(cfg.IPs), len(cfg.Policies))
 
 	// Create the firewall orchestrator (needs config for resolver)
 	orchestrator := firewall.NewOrchestrator(dockerClient, iptablesMgr, cfg)
@@ -84,12 +96,14 @@ func main() {
 
 	// Set up file watcher to detect changes and re-reconcile
 	onChange := func() {
-		log.Println("MAIN: config file change detected, reloading and reconciling")
+		log.Info("MAIN: config file change detected, reloading and reconciling")
 		newCfg, err := config.Load(configPath)
 		if err != nil {
-			log.Printf("MAIN: failed to reload config: %v", err)
+			log.Error("MAIN: failed to reload config: %v", err)
 			return
 		}
+		log.Info("MAIN: config reloaded: %d networks, %d IPs, %d policies",
+			len(newCfg.Networks), len(newCfg.IPs), len(newCfg.Policies))
 		orchestrator.ReconcileAll(ctx, newCfg)
 	}
 
@@ -101,7 +115,7 @@ func main() {
 	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
 
 	sig := <-sigCh
-	log.Printf("MAIN: received signal %v, shutting down", sig)
+	log.Info("MAIN: received signal %v, shutting down", sig)
 	fileWatcher.Stop()
-	log.Println("MAIN: shutdown complete")
+	log.Info("MAIN: shutdown complete")
 }