[KS-372] Lazy initialize the registrysyncer (#13787)

.changeset/healthy-lamps-argue.md

@@ -0,0 +1,5 @@
+---
+"chainlink": minor
+---
+
+Initialize registry syncer' contract reader lazily #keystone #internal

core/services/registrysyncer/syncer.go

@@ -35,9 +35,12 @@ type Syncer interface {
 }
 
 type registrySyncer struct {
-	stopCh    services.StopChan
-	launchers []Launcher
-	reader    types.ContractReader
+	stopCh          services.StopChan
+	launchers       []Launcher
+	reader          types.ContractReader
+	initReader      func(ctx context.Context, lggr logger.Logger, relayer contractReaderFactory, registryAddress string) (types.ContractReader, error)
+	relayer         contractReaderFactory
+	registryAddress string
 
 	wg   sync.WaitGroup
 	lggr logger.Logger
@@ -57,17 +60,13 @@ func New(
 	registryAddress string,
 ) (*registrySyncer, error) {
 	stopCh := make(services.StopChan)
-	ctx, _ := stopCh.NewCtx()
-	reader, err := newReader(ctx, lggr, relayer, registryAddress)
-	if err != nil {
-		return nil, err
-	}
-
-	return newSyncer(
-		stopCh,
-		lggr.Named("RegistrySyncer"),
-		reader,
-	), nil
+	return &registrySyncer{
+		stopCh:          stopCh,
+		lggr:            lggr,
+		relayer:         relayer,
+		registryAddress: registryAddress,
+		initReader:      newReader,
+	}, nil
 }
 
 type contractReaderFactory interface {
@@ -114,18 +113,6 @@ func newReader(ctx context.Context, lggr logger.Logger, relayer contractReaderFa
 	return cr, err
 }
 
-func newSyncer(
-	stopCh services.StopChan,
-	lggr logger.Logger,
-	reader types.ContractReader,
-) *registrySyncer {
-	return &registrySyncer{
-		stopCh: stopCh,
-		lggr:   lggr,
-		reader: reader,
-	}
-}
-
 func (s *registrySyncer) Start(ctx context.Context) error {
 	s.wg.Add(1)
 	go func() {
@@ -211,6 +198,15 @@ func (s *registrySyncer) sync(ctx context.Context) error {
 		return nil
 	}
 
+	if s.reader == nil {
+		reader, err := s.initReader(ctx, s.lggr, s.relayer, s.registryAddress)
+		if err != nil {
+			return err
+		}
+
+		s.reader = reader
+	}
+
 	state, err := s.state(ctx)
 	if err != nil {
 		return fmt.Errorf("failed to sync with remote registry: %w", err)

core/services/registrysyncer/syncer_test.go

@@ -116,6 +116,15 @@ func randomWord() [32]byte {
 	return [32]byte(word)
 }
 
+type launcher struct {
+	localRegistry State
+}
+
+func (l *launcher) Launch(ctx context.Context, localRegistry State) error {
+	l.localRegistry = localRegistry
+	return nil
+}
+
 func TestReader_Integration(t *testing.T) {
 	ctx := testutils.Context(t)
 	reg, regAddress, owner, sim := startNewChainWithRegistry(t)
@@ -192,10 +201,14 @@ func TestReader_Integration(t *testing.T) {
 	require.NoError(t, err)
 
 	factory := newContractReaderFactory(t, sim)
-	reader, err := New(logger.TestLogger(t), factory, regAddress.Hex())
+	syncer, err := New(logger.TestLogger(t), factory, regAddress.Hex())
 	require.NoError(t, err)
 
-	s, err := reader.state(ctx)
+	l := &launcher{}
+	syncer.AddLauncher(l)
+
+	err = syncer.sync(ctx)
+	s := l.localRegistry
 	require.NoError(t, err)
 	assert.Len(t, s.IDsToCapabilities, 1)