Skip redundant rescans on HELLO and speed up local full-scan indexing.

deploy/docker/Dockerfile.master-api

@@ -7,8 +7,8 @@ WORKDIR /src
 RUN apk add --no-cache git ca-certificates
 COPY node/media-node/ ./
 RUN go mod tidy \
- && CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X main.version=1.2.5" -o /media-node-linux-amd64 ./cmd/media-node \
+ && CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X main.version=1.2.6" -o /media-node-linux-amd64 ./cmd/media-node \
- && CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags="-s -w -X main.version=1.2.5" -o /media-node-linux-arm64 ./cmd/media-node
+ && CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags="-s -w -X main.version=1.2.6" -o /media-node-linux-arm64 ./cmd/media-node
 
 FROM base AS builder
 COPY package.json pnpm-workspace.yaml ./

node/media-node/cmd/media-node/main.go

@@ -24,7 +24,7 @@ import (
 	"github.com/sthmedia/media-node/internal/streaming"
 )
 
-var version = "1.2.5"
+var version = "1.2.6"
 
 func main() {
 	if len(os.Args) < 2 {

node/media-node/internal/control/client.go

@@ -283,12 +283,18 @@ func (c *Client) handleMessage(msgType string, payload json.RawMessage) {
 		}
 		log.Println("Connected to Master")
 		c.applyScannerSettings(ack.FullScanInterval, ack.FullScanAt, ack.FullScanIntervalSeconds)
+		rootsChanged := false
 		if len(ack.ScanRoots) > 0 {
-			c.applyScanRoots(ack.ScanRoots)
+			rootsChanged = c.applyScanRoots(ack.ScanRoots)
 		} else if len(ack.MoviesPaths) > 0 || len(ack.SeriesPaths) > 0 {
 			c.applyMediaPaths(ack.MoviesPaths, ack.SeriesPaths)
+			rootsChanged = true
+		}
+		// If roots changed, FullScan already started and will sync when done.
+		// Otherwise push current inventory (with shelfIds) to Master.
+		if !rootsChanged {
+			go c.sendFullSync()
 		}
-		go c.sendFullSync()
 	case "FULL_LIBRARY_SYNC_ACK":
 		var p struct {
 			Accepted   bool   `json:"accepted"`
@@ -418,7 +424,7 @@ func (c *Client) applyScanRoots(rows []struct {
 	Path    string `json:"path"`
 	ShelfID string `json:"shelfId"`
 	Kind    string `json:"kind"`
-}) {
+}) bool {
 	roots := make([]config.MediaRoot, 0, len(rows))
 	for _, r := range rows {
 		path := strings.TrimSpace(r.Path)
@@ -434,7 +440,7 @@ func (c *Client) applyScanRoots(rows []struct {
 		}
 		roots = append(roots, config.MediaRoot{Path: path, ShelfID: r.ShelfID, Kind: kind})
 	}
-	c.scanner.UpdateMediaRoots(roots)
+	changed := c.scanner.UpdateMediaRoots(roots)
 	c.cfg.Media.Roots = roots
 	var movies, series []string
 	for _, r := range roots {
@@ -446,11 +452,12 @@ func (c *Client) applyScanRoots(rows []struct {
 	}
 	c.cfg.Media.Movies = movies
 	c.cfg.Media.Series = series
-	if c.configPath != "" {
+	if changed && c.configPath != "" {
 		if err := config.Save(c.configPath, c.cfg); err != nil {
 			log.Printf("Failed to save media roots: %v", err)
 		}
 	}
+	return changed
 }
 
 func normalizePaths(in []string) []string {

node/media-node/internal/scanner/scanner.go

@@ -133,8 +133,14 @@ func (s *Scanner) UpdateMediaPaths(movies, series []string) {
 }
 
 // UpdateMediaRoots replaces scan roots (with optional shelf IDs).
-func (s *Scanner) UpdateMediaRoots(roots []config.MediaRoot) {
+// Returns true when roots changed (and a full scan was started).
+func (s *Scanner) UpdateMediaRoots(roots []config.MediaRoot) bool {
 	s.mu.Lock()
+	if mediaRootsEqual(s.cfg.Media.EffectiveRoots(), roots) {
+		s.mu.Unlock()
+		log.Printf("Media roots unchanged (%d roots) — skip rescan", len(roots))
+		return false
+	}
 	s.cfg.Media.Roots = append([]config.MediaRoot{}, roots...)
 	var movies, series []string
 	for _, r := range roots {
@@ -151,8 +157,23 @@ func (s *Scanner) UpdateMediaRoots(roots []config.MediaRoot) {
 	case s.reloadWatch <- struct{}{}:
 	default:
 	}
-	log.Printf("Media roots updated: %d roots", len(roots))
+	log.Printf("Media roots updated: %d roots — starting full scan", len(roots))
 	go s.FullScan()
+	return true
+}
+
+func mediaRootsEqual(a, b []config.MediaRoot) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if filepath.Clean(a[i].Path) != filepath.Clean(b[i].Path) ||
+			a[i].ShelfID != b[i].ShelfID ||
+			a[i].Kind != b[i].Kind {
+			return false
+		}
+	}
+	return true
 }
 
 func (s *Scanner) runStartupScan() {
@@ -491,7 +512,10 @@ func (s *Scanner) indexFile(path string, info os.FileInfo, eventType, preferredT
 	}
 
 	localFileID := database.FileID(path)
-	rev, _ := s.store.NextRevision()
+	var rev int64
+	if emitEvents {
+		rev, _ = s.store.NextRevision()
+	}
 
 	lf := database.LocalFile{
 		LocalFileID: localFileID,