Add sync manager protection to make sure only 1 go routine is triggered for a repo

Author: kushnaidu

pkg/cache/sync/sync.go

@@ -16,6 +16,7 @@ package sync
 
 import (
 	"context"
+	"sync"
 	"time"
 
 	configapi "github.com/nephio-project/porch/api/porchconfig/v1alpha1"
@@ -52,6 +53,8 @@ type SyncManager struct {
 	lastCronExpr  string
 	lastSyncError error
 	coreClient    client.WithWatch
+	mutex         sync.Mutex
+	running       bool
 }
 
 // NewSyncManager creates a new sync manager
@@ -65,6 +68,15 @@ func NewSyncManager(handler SyncHandler, coreClient client.WithWatch) *SyncManag
 
 // Start begins the sync process with periodic and one-time scheduling
 func (m *SyncManager) Start(ctx context.Context, defaultSyncFrequency time.Duration) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if m.running {
+		klog.Warningf("repositorySync %+v: already running, ignoring start request", m.handler.Key())
+		return
+	}
+	m.running = true
+
 	// Create cancellable context for goroutines
 	syncCtx, cancel := context.WithCancel(ctx)
 	m.cancel = cancel
@@ -75,9 +87,13 @@ func (m *SyncManager) Start(ctx context.Context, defaultSyncFrequency time.Durat
 
 // Stop stops the sync manager
 func (m *SyncManager) Stop() {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
 	if m.cancel != nil {
 		m.cancel()
 	}
+	m.running = false
 }
 
 // GetLastSyncError returns the last sync error

pkg/cache/sync/sync_test.go

@@ -348,6 +348,39 @@ func TestSyncManager_Start(t *testing.T) {
 	}
 }
 
+func TestSyncManager_Start_PreventMultipleStarts(t *testing.T) {
+	handler := &mockSyncHandler{
+		repoKey: repository.RepositoryKey{Name: "test-repo", Namespace: "test-ns"},
+	}
+	manager := NewSyncManager(handler, nil)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// First start should succeed
+	manager.Start(ctx, 1*time.Second)
+	assert.True(t, manager.running, "Manager should be running after first start")
+
+	// Parallel starts should be ignored and not increase syncCount
+	manager.Start(ctx, 1*time.Second)
+	manager.Start(ctx, 1*time.Second)
+	manager.Start(ctx, 1*time.Second)
+
+	// Wait to ensure no additional goroutines were started
+	time.Sleep(100 * time.Millisecond)
+
+	// Sync count should not have increased
+	assert.Equal(t, handler.syncCount, 1, "Parallel starts should not create additional sync activity")
+
+	// Stop and verify we can start again
+	manager.Stop()
+	assert.False(t, manager.running, "Manager should not be running after stop")
+
+	// Should be able to start again after stop
+	manager.Start(ctx, 1*time.Second)
+	assert.True(t, manager.running, "Manager should be running after restart")
+}
+
 func TestSyncManager_HasValidSyncSpec(t *testing.T) {
 	tests := []struct {
 		name     string