Implement routing table snapshotter with automatic loading on startup

- Create snapshotter package with periodic (10 min) and on-demand snapshots
- Add JSON serialization with gzip compression and atomic file writes
- Update routing table to track AddedAt time for each route
- Load snapshots on startup, filtering out stale routes (>30 minutes old)
- Add ROUTEWATCH_DISABLE_SNAPSHOTTER env var for tests
- Use OS-appropriate state directories (macOS: ~/Library/Application Support, Linux: /var/lib or XDG_STATE_HOME)

internal/routewatch/app.go

@@ -14,6 +14,7 @@ import (
 	"git.eeqj.de/sneak/routewatch/internal/metrics"
 	"git.eeqj.de/sneak/routewatch/internal/routingtable"
 	"git.eeqj.de/sneak/routewatch/internal/server"
+	"git.eeqj.de/sneak/routewatch/internal/snapshotter"
 	"git.eeqj.de/sneak/routewatch/internal/streamer"
 
 	"go.uber.org/fx"
@@ -54,13 +55,14 @@ type RouteWatch struct {
 	routingTable *routingtable.RoutingTable
 	streamer     *streamer.Streamer
 	server       *server.Server
+	snapshotter  *snapshotter.Snapshotter
 	logger       *slog.Logger
 	maxRuntime   time.Duration
 }
 
 // New creates a new RouteWatch instance
 func New(deps Dependencies) *RouteWatch {
-	return &RouteWatch{
+	rw := &RouteWatch{
 		db:           deps.DB,
 		routingTable: deps.RoutingTable,
 		streamer:     deps.Streamer,
@@ -68,6 +70,19 @@ func New(deps Dependencies) *RouteWatch {
 		logger:       deps.Logger,
 		maxRuntime:   deps.Config.MaxRuntime,
 	}
+
+	// Create snapshotter unless disabled (for tests)
+	if os.Getenv("ROUTEWATCH_DISABLE_SNAPSHOTTER") != "1" {
+		snapshotter, err := snapshotter.New(deps.RoutingTable, deps.Logger)
+		if err != nil {
+			deps.Logger.Error("Failed to create snapshotter", "error", err)
+			// Continue without snapshotter
+		} else {
+			rw.snapshotter = snapshotter
+		}
+	}
+
+	return rw
 }
 
 // Run starts the RouteWatch application
@@ -97,6 +112,11 @@ func (rw *RouteWatch) Run(ctx context.Context) error {
 	// Start periodic routing table stats logging
 	go rw.logRoutingTableStats(ctx)
 
+	// Start snapshotter if available
+	if rw.snapshotter != nil {
+		rw.snapshotter.Start(ctx)
+	}
+
 	// Start streaming
 	if err := rw.streamer.Start(); err != nil {
 		return err
@@ -131,6 +151,13 @@ func (rw *RouteWatch) Run(ctx context.Context) error {
 		"duration", time.Since(metrics.ConnectedSince),
 	)
 
+	// Take final snapshot before shutdown if snapshotter is available
+	if rw.snapshotter != nil {
+		if err := rw.snapshotter.Shutdown(); err != nil {
+			rw.logger.Error("Failed to shutdown snapshotter", "error", err)
+		}
+	}
+
 	return nil
 }
 
@@ -199,10 +226,7 @@ func getModule() fx.Option {
 			),
 			routingtable.New,
 			streamer.New,
-			fx.Annotate(
-				server.New,
-				fx.ParamTags(``, ``, ``, ``),
-			),
+			server.New,
 			New,
 		),
 	)

internal/routewatch/app_integration_test.go

@@ -156,6 +156,9 @@ func (m *mockStore) GetStats() (database.Stats, error) {
 }
 
 func TestRouteWatchLiveFeed(t *testing.T) {
+	// Disable snapshotter for tests
+	t.Setenv("ROUTEWATCH_DISABLE_SNAPSHOTTER", "1")
+
 	// Create mock database
 	mockDB := newMockStore()
 	defer mockDB.Close()
@@ -169,7 +172,7 @@ func TestRouteWatchLiveFeed(t *testing.T) {
 	s := streamer.New(logger, metricsTracker)
 
 	// Create routing table
-	rt := routingtable.New()
+	rt := routingtable.New(logger)
 
 	// Create server
 	srv := server.New(mockDB, rt, s, logger)

internal/routewatch/dbhandler.go

@@ -9,7 +9,7 @@ import (
 
 const (
 	// databaseHandlerQueueSize is the queue capacity for database operations
-	databaseHandlerQueueSize = 100
+	databaseHandlerQueueSize = 200
 )
 
 // DatabaseHandler handles BGP messages and stores them in the database
@@ -19,7 +19,10 @@ type DatabaseHandler struct {
 }
 
 // NewDatabaseHandler creates a new database handler
-func NewDatabaseHandler(db database.Store, logger *slog.Logger) *DatabaseHandler {
+func NewDatabaseHandler(
+	db database.Store,
+	logger *slog.Logger,
+) *DatabaseHandler {
 	return &DatabaseHandler{
 		db:     db,
 		logger: logger,
@@ -55,7 +58,13 @@ func (h *DatabaseHandler) HandleMessage(msg *ristypes.RISMessage) {
 			// Get or create prefix
 			_, err := h.db.GetOrCreatePrefix(prefix, timestamp)
 			if err != nil {
-				h.logger.Error("Failed to get/create prefix", "prefix", prefix, "error", err)
+				h.logger.Error(
+					"Failed to get/create prefix",
+					"prefix",
+					prefix,
+					"error",
+					err,
+				)
 
 				continue
 			}
@@ -63,7 +72,13 @@ func (h *DatabaseHandler) HandleMessage(msg *ristypes.RISMessage) {
 			// Get or create origin ASN
 			_, err = h.db.GetOrCreateASN(originASN, timestamp)
 			if err != nil {
-				h.logger.Error("Failed to get/create ASN", "asn", originASN, "error", err)
+				h.logger.Error(
+					"Failed to get/create ASN",
+					"asn",
+					originASN,
+					"error",
+					err,
+				)
 
 				continue
 			}
@@ -78,20 +93,36 @@ func (h *DatabaseHandler) HandleMessage(msg *ristypes.RISMessage) {
 					// Get or create both ASNs
 					fromAS, err := h.db.GetOrCreateASN(fromASN, timestamp)
 					if err != nil {
-						h.logger.Error("Failed to get/create from ASN", "asn", fromASN, "error", err)
+						h.logger.Error(
+							"Failed to get/create from ASN",
+							"asn",
+							fromASN,
+							"error",
+							err,
+						)
 
 						continue
 					}
 
 					toAS, err := h.db.GetOrCreateASN(toASN, timestamp)
 					if err != nil {
-						h.logger.Error("Failed to get/create to ASN", "asn", toASN, "error", err)
+						h.logger.Error(
+							"Failed to get/create to ASN",
+							"asn",
+							toASN,
+							"error",
+							err,
+						)
 
 						continue
 					}
 
 					// Record the peering
-					err = h.db.RecordPeering(fromAS.ID.String(), toAS.ID.String(), timestamp)
+					err = h.db.RecordPeering(
+						fromAS.ID.String(),
+						toAS.ID.String(),
+						timestamp,
+					)
 					if err != nil {
 						h.logger.Error("Failed to record peering",
 							"from_asn", fromASN,
@@ -109,7 +140,13 @@ func (h *DatabaseHandler) HandleMessage(msg *ristypes.RISMessage) {
 		// Get prefix
 		_, err := h.db.GetOrCreatePrefix(prefix, timestamp)
 		if err != nil {
-			h.logger.Error("Failed to get prefix for withdrawal", "prefix", prefix, "error", err)
+			h.logger.Error(
+				"Failed to get prefix for withdrawal",
+				"prefix",
+				prefix,
+				"error",
+				err,
+			)
 
 			continue
 		}

internal/routingtable/routingtable.go

@@ -2,7 +2,13 @@
 package routingtable
 
 import (
+	"compress/gzip"
+	"encoding/json"
 	"fmt"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"runtime"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -11,6 +17,15 @@ import (
 	"github.com/google/uuid"
 )
 
+const (
+	// routeStalenessThreshold is how old a route can be before we consider it stale
+	// Using 30 minutes as a conservative value for snapshot loading
+	routeStalenessThreshold = 30 * time.Minute
+
+	// snapshotFilename is the name of the snapshot file
+	snapshotFilename = "routewatch-snapshot.json.gz"
+)
+
 // Route represents a single route entry in the routing table
 type Route struct {
 	PrefixID    uuid.UUID `json:"prefix_id"`
@@ -21,6 +36,7 @@ type Route struct {
 	ASPath      []int     `json:"as_path"` // Full AS path
 	NextHop     string    `json:"next_hop"`
 	AnnouncedAt time.Time `json:"announced_at"`
+	AddedAt     time.Time `json:"added_at"` // When we added this route to our table
 }
 
 // RouteKey uniquely identifies a route in the table
@@ -48,15 +64,22 @@ type RoutingTable struct {
 	lastMetricsReset time.Time
 }
 
-// New creates a new empty routing table
-func New() *RoutingTable {
-	return &RoutingTable{
+// New creates a new routing table, loading from snapshot if available
+func New(logger *slog.Logger) *RoutingTable {
+	rt := &RoutingTable{
 		routes:           make(map[RouteKey]*Route),
 		byPrefix:         make(map[uuid.UUID]map[RouteKey]*Route),
 		byOriginASN:      make(map[uuid.UUID]map[RouteKey]*Route),
 		byPeerASN:        make(map[int]map[RouteKey]*Route),
 		lastMetricsReset: time.Now(),
 	}
+
+	// Try to load from snapshot
+	if err := rt.loadFromSnapshot(logger); err != nil {
+		logger.Warn("Failed to load routing table from snapshot", "error", err)
+	}
+
+	return rt
 }
 
 // AddRoute adds or updates a route in the routing table
@@ -81,6 +104,11 @@ func (rt *RoutingTable) AddRoute(route *Route) {
 		}
 	}
 
+	// Set AddedAt if not already set
+	if route.AddedAt.IsZero() {
+		route.AddedAt = time.Now().UTC()
+	}
+
 	// Add to main map
 	rt.routes[key] = route
 
@@ -357,6 +385,7 @@ func (rt *RoutingTable) GetAllRoutesUnsafe() []*Route {
 	for _, route := range rt.routes {
 		routes = append(routes, route)
 	}
+
 	return routes
 }
 
@@ -417,3 +446,108 @@ func (k RouteKey) String() string {
 func isIPv6(prefix string) bool {
 	return strings.Contains(prefix, ":")
 }
+
+// getStateDirectory returns the appropriate state directory based on the OS
+func getStateDirectory() (string, error) {
+	switch runtime.GOOS {
+	case "darwin":
+		// macOS: Use ~/Library/Application Support/routewatch
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+
+		return filepath.Join(home, "Library", "Application Support", "routewatch"), nil
+	case "linux", "freebsd", "openbsd", "netbsd":
+		// Unix-like: Use /var/lib/routewatch if running as root, otherwise use XDG_STATE_HOME
+		if os.Geteuid() == 0 {
+			return "/var/lib/routewatch", nil
+		}
+		// Check XDG_STATE_HOME first
+		if xdgState := os.Getenv("XDG_STATE_HOME"); xdgState != "" {
+			return filepath.Join(xdgState, "routewatch"), nil
+		}
+		// Fall back to ~/.local/state/routewatch
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+
+		return filepath.Join(home, ".local", "state", "routewatch"), nil
+	default:
+		return "", fmt.Errorf("unsupported operating system: %s", runtime.GOOS)
+	}
+}
+
+// loadFromSnapshot attempts to load the routing table from a snapshot file
+func (rt *RoutingTable) loadFromSnapshot(logger *slog.Logger) error {
+	stateDir, err := getStateDirectory()
+	if err != nil {
+		return fmt.Errorf("failed to determine state directory: %w", err)
+	}
+
+	snapshotPath := filepath.Join(stateDir, snapshotFilename)
+
+	// Check if snapshot file exists
+	if _, err := os.Stat(snapshotPath); os.IsNotExist(err) {
+		logger.Info("No snapshot file found, starting with empty routing table")
+
+		return nil
+	}
+
+	// Open the snapshot file
+	file, err := os.Open(filepath.Clean(snapshotPath))
+	if err != nil {
+		return fmt.Errorf("failed to open snapshot file: %w", err)
+	}
+	defer func() { _ = file.Close() }()
+
+	// Create gzip reader
+	gzReader, err := gzip.NewReader(file)
+	if err != nil {
+		return fmt.Errorf("failed to create gzip reader: %w", err)
+	}
+	defer func() { _ = gzReader.Close() }()
+
+	// Decode the snapshot
+	var snapshot struct {
+		Timestamp time.Time     `json:"timestamp"`
+		Stats     DetailedStats `json:"stats"`
+		Routes    []*Route      `json:"routes"`
+	}
+
+	decoder := json.NewDecoder(gzReader)
+	if err := decoder.Decode(&snapshot); err != nil {
+		return fmt.Errorf("failed to decode snapshot: %w", err)
+	}
+
+	// Calculate staleness cutoff time
+	now := time.Now().UTC()
+	cutoffTime := now.Add(-routeStalenessThreshold)
+
+	// Load non-stale routes
+	loadedCount := 0
+	staleCount := 0
+
+	for _, route := range snapshot.Routes {
+		// Check if route is stale based on AddedAt time
+		if route.AddedAt.Before(cutoffTime) {
+			staleCount++
+
+			continue
+		}
+
+		// Add the route (this will update counters and indexes)
+		rt.AddRoute(route)
+		loadedCount++
+	}
+
+	logger.Info("Loaded routing table from snapshot",
+		"snapshot_time", snapshot.Timestamp,
+		"loaded_routes", loadedCount,
+		"stale_routes", staleCount,
+		"total_routes_in_snapshot", len(snapshot.Routes),
+	)
+
+	return nil
+}

internal/routingtable/routingtable_test.go

@@ -1,6 +1,7 @@
 package routingtable
 
 import (
+	"log/slog"
 	"sync"
 	"testing"
 	"time"
@@ -9,7 +10,9 @@ import (
 )
 
 func TestRoutingTable(t *testing.T) {
-	rt := New()
+	// Create a test logger
+	logger := slog.Default()
+	rt := New(logger)
 
 	// Test data
 	prefixID1 := uuid.New()
@@ -118,7 +121,9 @@ func TestRoutingTable(t *testing.T) {
 }
 
 func TestRoutingTableConcurrency(t *testing.T) {
-	rt := New()
+	// Create a test logger
+	logger := slog.Default()
+	rt := New(logger)
 
 	// Test concurrent access
 	var wg sync.WaitGroup
@@ -170,7 +175,9 @@ func TestRoutingTableConcurrency(t *testing.T) {
 }
 
 func TestRouteUpdate(t *testing.T) {
-	rt := New()
+	// Create a test logger
+	logger := slog.Default()
+	rt := New(logger)
 
 	prefixID := uuid.New()
 	originASNID := uuid.New()

internal/snapshotter/snapshotter.go

@@ -36,32 +36,44 @@ type Snapshotter struct {
 }
 
 // New creates a new Snapshotter instance
-func New(ctx context.Context, rt *routingtable.RoutingTable, logger *slog.Logger) (*Snapshotter, error) {
+func New(rt *routingtable.RoutingTable, logger *slog.Logger) (*Snapshotter, error) {
 	stateDir, err := getStateDirectory()
 	if err != nil {
 		return nil, fmt.Errorf("failed to determine state directory: %w", err)
 	}
 
 	// Ensure state directory exists
-	if err := os.MkdirAll(stateDir, 0755); err != nil {
+	const stateDirPerms = 0750
+	if err := os.MkdirAll(stateDir, stateDirPerms); err != nil {
 		return nil, fmt.Errorf("failed to create state directory: %w", err)
 	}
 
-	ctx, cancel := context.WithCancel(ctx)
-
 	s := &Snapshotter{
 		rt:       rt,
 		stateDir: stateDir,
 		logger:   logger,
-		ctx:      ctx,
-		cancel:   cancel,
 	}
 
+	return s, nil
+}
+
+// Start begins the periodic snapshot process
+func (s *Snapshotter) Start(ctx context.Context) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if s.ctx != nil {
+		// Already started
+		return
+	}
+
+	ctx, cancel := context.WithCancel(ctx)
+	s.ctx = ctx
+	s.cancel = cancel
+
 	// Start periodic snapshot goroutine
 	s.wg.Add(1)
 	go s.periodicSnapshot()
-
-	return s, nil
 }
 
 // getStateDirectory returns the appropriate state directory based on the OS
@@ -73,6 +85,7 @@ func getStateDirectory() (string, error) {
 		if err != nil {
 			return "", err
 		}
+
 		return filepath.Join(home, "Library", "Application Support", "routewatch"), nil
 	case "linux", "freebsd", "openbsd", "netbsd":
 		// Unix-like: Use /var/lib/routewatch if running as root, otherwise use XDG_STATE_HOME
@@ -88,6 +101,7 @@ func getStateDirectory() (string, error) {
 		if err != nil {
 			return "", err
 		}
+
 		return filepath.Join(home, ".local", "state", "routewatch"), nil
 	default:
 		return "", fmt.Errorf("unsupported operating system: %s", runtime.GOOS)
@@ -154,19 +168,23 @@ func (s *Snapshotter) TakeSnapshot() error {
 	tempPath := filepath.Join(s.stateDir, snapshotFilename+tempFileSuffix)
 	finalPath := filepath.Join(s.stateDir, snapshotFilename)
 
+	// Clean the paths to avoid any path traversal issues
+	tempPath = filepath.Clean(tempPath)
+	finalPath = filepath.Clean(finalPath)
+
 	tempFile, err := os.Create(tempPath)
 	if err != nil {
 		return fmt.Errorf("failed to create temporary file: %w", err)
 	}
 	defer func() {
-		tempFile.Close()
+		_ = tempFile.Close()
 		// Clean up temp file if it still exists
-		os.Remove(tempPath)
+		_ = os.Remove(tempPath)
 	}()
 
 	// Create gzip writer
 	gzipWriter := gzip.NewWriter(tempFile)
-	gzipWriter.Header.Comment = fmt.Sprintf("RouteWatch snapshot taken at %s", snapshot.Timestamp.Format(time.RFC3339))
+	gzipWriter.Comment = fmt.Sprintf("RouteWatch snapshot taken at %s", snapshot.Timestamp.Format(time.RFC3339))
 
 	// Write compressed data
 	if _, err := gzipWriter.Write(jsonData); err != nil {
@@ -213,7 +231,9 @@ func (s *Snapshotter) Shutdown() error {
 	s.logger.Info("Shutting down snapshotter")
 
 	// Cancel context to stop periodic snapshots
-	s.cancel()
+	if s.cancel != nil {
+		s.cancel()
+	}
 
 	// Wait for periodic snapshot goroutine to finish
 	s.wg.Wait()
@@ -230,6 +250,7 @@ func (s *Snapshotter) Shutdown() error {
 func (s *Snapshotter) GetLastSnapshotTime() time.Time {
 	s.mu.Lock()
 	defer s.mu.Unlock()
+
 	return s.lastSnapshot
 }