internal/controller/worker/grpc_handler.go

@@ -2,13 +2,11 @@ package worker
 
 import (
 	"context"
-	"crypto/sha256"
 	"errors"
 
 	controlplanev1 "proxy-pool/gen/controlplane/v1"
 	"proxy-pool/internal/domain/workerruntime"
 
-	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/types/known/durationpb"
@@ -23,15 +21,10 @@ type GRPCHandler struct {
 	controlplanev1.UnimplementedWorkerControlPlaneServer
 	service  Service
 	identity IdentityAuthorizer
-	snapshots SnapshotSource
 }
 
-func NewGRPCHandler(service Service, identity IdentityAuthorizer, snapshots ...SnapshotSource) *GRPCHandler {
+func NewGRPCHandler(service Service, identity IdentityAuthorizer) *GRPCHandler {
-	handler := &GRPCHandler{service: service, identity: identity}
+	return &GRPCHandler{service: service, identity: identity}
-	if len(snapshots) == 1 {
-		handler.snapshots = snapshots[0]
-	}
-	return handler
 }
 
 func (handler *GRPCHandler) RegisterWorker(ctx context.Context, request *controlplanev1.RegisterWorkerRequest) (*controlplanev1.RegisterWorkerResponse, error) {
@@ -54,58 +47,6 @@ func (handler *GRPCHandler) RegisterWorker(ctx context.Context, request *control
 	}, nil
 }
 
-func (handler *GRPCHandler) WatchSnapshots(request *controlplanev1.WatchSnapshotsRequest, stream grpc.ServerStreamingServer[controlplanev1.SnapshotEnvelope]) error {
-	if request == nil || stream == nil || handler == nil || handler.service == nil || handler.identity == nil {
-		return grpcError(ErrInvalidCommand)
-	}
-	if handler.snapshots == nil {
-		return status.Error(codes.Unimplemented, "worker snapshots are unavailable")
-	}
-	if err := handler.authorize(stream.Context(), request.GetWorkerId()); err != nil {
-		return err
-	}
-	if !workerruntime.ValidIdentifier(request.GetWorkerId()) || !workerruntime.ValidIdentifier(request.GetSessionId()) ||
-		(len(request.GetLastChecksum()) != 0 && len(request.GetLastChecksum()) != sha256.Size) {
-		return grpcError(ErrInvalidCommand)
-	}
-	updates, err := handler.snapshots.Watch(stream.Context(), SnapshotWatchRequest{
-		WorkerID: request.GetWorkerId(), SessionID: request.GetSessionId(), LastAppliedVersion: request.GetLastAppliedVersion(),
-		LastChecksum: append([]byte(nil), request.GetLastChecksum()...),
-	})
-	if err != nil {
-		return grpcError(err)
-	}
-	for {
-		select {
-		case <-stream.Context().Done():
-			return stream.Context().Err()
-		case snapshot, ok := <-updates:
-			if !ok {
-				return nil
-			}
-			if err := handler.issueSnapshot(stream.Context(), request.GetWorkerId(), snapshot); err != nil {
-				return grpcError(err)
-			}
-			if err := stream.Send(&controlplanev1.SnapshotEnvelope{Payload: &controlplanev1.SnapshotEnvelope_Full{Full: snapshot}}); err != nil {
-				return err
-			}
-		}
-	}
-}
-
-func (handler *GRPCHandler) issueSnapshot(ctx context.Context, workerID string, snapshot *controlplanev1.WorkerSnapshot) error {
-	if snapshot == nil || snapshot.GetVersion() == 0 || snapshot.GetOwnershipEpoch() == 0 || len(snapshot.GetChecksum()) != sha256.Size ||
-		snapshot.GetGeneratedAt() == nil || snapshot.GetGeneratedAt().CheckValid() != nil ||
-		snapshot.GetValidUntil() == nil || snapshot.GetValidUntil().CheckValid() != nil {
-		return ErrInvalidCommand
-	}
-	var checksum [sha256.Size]byte
-	copy(checksum[:], snapshot.GetChecksum())
-	return handler.service.IssueSnapshot(ctx, workerruntime.SnapshotReference{
-		WorkerID: workerID, Version: snapshot.GetVersion(), OwnershipEpoch: snapshot.GetOwnershipEpoch(), Checksum: checksum,
-	})
-}
-
 func (handler *GRPCHandler) AcknowledgeSnapshot(ctx context.Context, request *controlplanev1.AcknowledgeSnapshotRequest) (*emptypb.Empty, error) {
 	if request == nil || handler == nil || handler.service == nil || handler.identity == nil {
 		return nil, grpcError(ErrInvalidCommand)

internal/controller/worker/grpc_handler_test.go

@@ -64,29 +64,6 @@ func TestGRPCHandlerMapsErrorsAndLeavesStreamsUnimplemented(t *testing.T) {
 	}
 }
 
-func TestGRPCHandlerStreamsIssuedFullSnapshots(t *testing.T) {
-	checksum := make([]byte, 32)
-	checksum[0] = 1
-	full := &controlplanev1.WorkerSnapshot{
-		Version: 3, OwnershipEpoch: 9, Checksum: checksum,
-		GeneratedAt: timestamppb.New(time.Now()), ValidUntil: timestamppb.New(time.Now().Add(time.Minute)),
-	}
-	service := &grpcServiceStub{}
-	client, cleanup := grpcWorkerClient(t, service, allowIdentity{}, snapshotSourceStub{snapshots: []*controlplanev1.WorkerSnapshot{full}})
-	defer cleanup()
-	stream, err := client.WatchSnapshots(context.Background(), &controlplanev1.WatchSnapshotsRequest{WorkerId: "worker-a", SessionId: "session-a"})
-	if err != nil {
-		t.Fatalf("WatchSnapshots(): %v", err)
-	}
-	received, err := stream.Recv()
-	if err != nil || received.GetFull().GetVersion() != 3 {
-		t.Fatalf("Recv() = %+v, %v", received, err)
-	}
-	if service.issued.WorkerID != "worker-a" || service.issued.Version != 3 || service.issued.Checksum[0] != 1 {
-		t.Fatalf("issued snapshot = %+v", service.issued)
-	}
-}
-
 type grpcServiceStub struct {
 	registration    Registration
 	registerErr     error
@@ -94,16 +71,11 @@ type grpcServiceStub struct {
 	acknowledgeErr  error
 	report          workerruntime.Report
 	reportErr       error
-	issued          workerruntime.SnapshotReference
 }
 
 func (stub *grpcServiceStub) Register(context.Context, RegisterCommand) (Registration, error) {
 	return stub.registration, stub.registerErr
 }
-func (stub *grpcServiceStub) IssueSnapshot(_ context.Context, reference workerruntime.SnapshotReference) error {
-	stub.issued = reference
-	return nil
-}
 func (stub *grpcServiceStub) Acknowledge(_ context.Context, acknowledgement SnapshotAcknowledgement) error {
 	stub.acknowledgement = acknowledgement
 	return stub.acknowledgeErr
@@ -117,24 +89,11 @@ type allowIdentity struct{}
 
 func (allowIdentity) Authorize(context.Context, string) error { return nil }
 
-type snapshotSourceStub struct {
+func grpcWorkerClient(t *testing.T, service Service, identity IdentityAuthorizer) (controlplanev1.WorkerControlPlaneClient, func()) {
-	snapshots []*controlplanev1.WorkerSnapshot
-}
-
-func (source snapshotSourceStub) Watch(_ context.Context, _ SnapshotWatchRequest) (<-chan *controlplanev1.WorkerSnapshot, error) {
-	updates := make(chan *controlplanev1.WorkerSnapshot, len(source.snapshots))
-	for _, snapshot := range source.snapshots {
-		updates <- snapshot
-	}
-	close(updates)
-	return updates, nil
-}
-
-func grpcWorkerClient(t *testing.T, service Service, identity IdentityAuthorizer, snapshots ...SnapshotSource) (controlplanev1.WorkerControlPlaneClient, func()) {
 	t.Helper()
 	listener := bufconn.Listen(1 << 20)
 	server := grpc.NewServer()
-	controlplanev1.RegisterWorkerControlPlaneServer(server, NewGRPCHandler(service, identity, snapshots...))
+	controlplanev1.RegisterWorkerControlPlaneServer(server, NewGRPCHandler(service, identity))
 	go func() { _ = server.Serve(listener) }()
 	connection, err := grpc.NewClient("passthrough:///bufnet", grpc.WithContextDialer(func(context.Context, string) (net.Conn, error) { return listener.Dial() }), grpc.WithInsecure())
 	if err != nil {

internal/controller/worker/server.go

@@ -23,7 +23,6 @@ var ErrInvalidServer = errors.New("invalid worker control server configuration")
 
 type ServerOptions struct {
 	ShutdownTimeout time.Duration
-	Snapshots       SnapshotSource
 }
 
 func DefaultServerOptions() ServerOptions {
@@ -61,7 +60,7 @@ func NewServer(controlPlane config.ControlPlane, service Service, options Server
 		}),
 	)
 	grpcServer := grpc.NewServer(serverOptions...)
-	controlplanev1.RegisterWorkerControlPlaneServer(grpcServer, NewGRPCHandler(service, identity, options.Snapshots))
+	controlplanev1.RegisterWorkerControlPlaneServer(grpcServer, NewGRPCHandler(service, identity))
 	return &Server{listen: controlPlane.Listen, grpcServer: grpcServer, shutdownTimeout: options.ShutdownTimeout}, nil
 }
 

internal/controller/worker/service.go

@@ -60,28 +60,10 @@ type Options struct {
 
 type Service interface {
 	Register(context.Context, RegisterCommand) (Registration, error)
-	IssueSnapshot(context.Context, workerruntime.SnapshotReference) error
 	Acknowledge(context.Context, SnapshotAcknowledgement) error
 	ReportRuntime(context.Context, workerruntime.Report) (RuntimeDecision, error)
 }
 
-func (service *service) IssueSnapshot(ctx context.Context, reference workerruntime.SnapshotReference) error {
-	if ctx == nil {
-		return ErrInvalidCommand
-	}
-	if err := ctx.Err(); err != nil {
-		return err
-	}
-	normalized, err := workerruntime.NormalizeSnapshotReference(reference)
-	if err != nil {
-		return errors.Join(ErrInvalidCommand, err)
-	}
-	if err := service.store.RecordIssuedSnapshot(ctx, normalized, service.options.SessionTTL); err != nil {
-		return classifyStoreError(err)
-	}
-	return nil
-}
-
 type service struct {
 	store   workerruntime.ControlStore
 	options Options

internal/controller/worker/service_test.go

@@ -35,8 +35,8 @@ func TestServiceRegistersAcknowledgesAndReportsRuntime(t *testing.T) {
 		WorkerID: "worker-a", Version: 7, OwnershipEpoch: registered.OwnershipEpoch,
 		Checksum: sha256.Sum256([]byte("snapshot-7")),
 	}
-	if err := service.IssueSnapshot(context.Background(), reference); err != nil {
+	if err := store.RecordIssuedSnapshot(context.Background(), reference, time.Minute); err != nil {
-		t.Fatalf("IssueSnapshot(): %v", err)
+		t.Fatalf("RecordIssuedSnapshot(): %v", err)
 	}
 	if err := service.Acknowledge(context.Background(), SnapshotAcknowledgement{
 		WorkerID: "worker-a", SessionID: registered.SessionID, Version: 7,

internal/controller/worker/snapshot_source.go

@@ -1,21 +0,0 @@
-package worker
-
-import (
-	"context"
-	"errors"
-
-	controlplanev1 "proxy-pool/gen/controlplane/v1"
-)
-
-var ErrSnapshotsUnavailable = errors.New("worker snapshots are unavailable")
-
-type SnapshotWatchRequest struct {
-	WorkerID           string
-	SessionID          string
-	LastAppliedVersion uint64
-	LastChecksum       []byte
-}
-
-type SnapshotSource interface {
-	Watch(context.Context, SnapshotWatchRequest) (<-chan *controlplanev1.WorkerSnapshot, error)
-}

internal/gateway/controlplane/watcher.go

@@ -1,223 +0,0 @@
-package controlplane
-
-import (
-	"context"
-	"crypto/sha256"
-	"errors"
-	"fmt"
-	"io"
-	"math"
-	"time"
-
-	controlplanev1 "proxy-pool/gen/controlplane/v1"
-	proxyDomain "proxy-pool/internal/domain/proxy"
-	"proxy-pool/internal/domain/workerruntime"
-	"proxy-pool/internal/gateway/snapshot"
-
-	"google.golang.org/grpc"
-	"google.golang.org/protobuf/proto"
-	"google.golang.org/protobuf/types/known/emptypb"
-	"google.golang.org/protobuf/types/known/timestamppb"
-)
-
-var (
-	ErrInvalidSnapshotWatcher = errors.New("invalid gateway snapshot watcher")
-	ErrSnapshotChecksum       = errors.New("worker snapshot checksum mismatch")
-	ErrSnapshotDelta          = errors.New("worker snapshot delta requires a full snapshot")
-)
-
-type SnapshotStream interface {
-	Recv() (*controlplanev1.SnapshotEnvelope, error)
-}
-
-type SnapshotRPCClient interface {
-	Watch(context.Context, *controlplanev1.WatchSnapshotsRequest) (SnapshotStream, error)
-	Acknowledge(context.Context, *controlplanev1.AcknowledgeSnapshotRequest) (*emptypb.Empty, error)
-}
-
-type SnapshotWatcherOptions struct {
-	ClusterID string
-	WorkerID  string
-}
-
-type SnapshotWatcher struct {
-	client  SnapshotRPCClient
-	store   *snapshot.Store
-	options SnapshotWatcherOptions
-}
-
-func NewSnapshotWatcher(client SnapshotRPCClient, store *snapshot.Store, options SnapshotWatcherOptions) (*SnapshotWatcher, error) {
-	if client == nil || store == nil || !workerruntime.ValidIdentifier(options.ClusterID) || !workerruntime.ValidIdentifier(options.WorkerID) {
-		return nil, ErrInvalidSnapshotWatcher
-	}
-	return &SnapshotWatcher{client: client, store: store, options: options}, nil
-}
-
-// Watch applies verified full snapshots in stream order. Delta support remains
-// intentionally fail-closed until the Gateway can validate a complete routing view.
-func (watcher *SnapshotWatcher) Watch(ctx context.Context, sessionID string) error {
-	if watcher == nil || ctx == nil || !workerruntime.ValidIdentifier(sessionID) {
-		return ErrInvalidSnapshotWatcher
-	}
-	request := &controlplanev1.WatchSnapshotsRequest{WorkerId: watcher.options.WorkerID, SessionId: sessionID}
-	if current := watcher.store.Current(); current != nil {
-		request.LastAppliedVersion = current.Version
-	}
-	stream, err := watcher.client.Watch(ctx, request)
-	if err != nil {
-		return err
-	}
-	for {
-		envelope, err := stream.Recv()
-		if errors.Is(err, io.EOF) {
-			return nil
-		}
-		if err != nil {
-			return err
-		}
-		if err := watcher.applyAndAcknowledge(ctx, sessionID, envelope); err != nil {
-			return err
-		}
-	}
-}
-
-func (watcher *SnapshotWatcher) applyAndAcknowledge(ctx context.Context, sessionID string, envelope *controlplanev1.SnapshotEnvelope) error {
-	if envelope == nil || envelope.GetFull() == nil {
-		return ErrSnapshotDelta
-	}
-	full := envelope.GetFull()
-	applyErr := watcher.applyFull(full)
-	if len(full.GetChecksum()) != sha256.Size {
-		return errors.Join(applyErr, ErrSnapshotChecksum)
-	}
-	acknowledgement := &controlplanev1.AcknowledgeSnapshotRequest{
-		WorkerId: watcher.options.WorkerID, SessionId: sessionID, Version: full.GetVersion(),
-		OwnershipEpoch: full.GetOwnershipEpoch(), Checksum: append([]byte(nil), full.GetChecksum()...),
-		Applied: applyErr == nil,
-	}
-	if applyErr != nil {
-		acknowledgement.ErrorCode = "snapshot_apply_failed"
-	}
-	_, acknowledgeErr := watcher.client.Acknowledge(ctx, acknowledgement)
-	if applyErr != nil || acknowledgeErr != nil {
-		return errors.Join(applyErr, acknowledgeErr)
-	}
-	return nil
-}
-
-func (watcher *SnapshotWatcher) applyFull(full *controlplanev1.WorkerSnapshot) error {
-	if full == nil || full.GetVersion() == 0 || full.GetOwnershipEpoch() == 0 {
-		return ErrInvalidSnapshotWatcher
-	}
-	checksum, err := workerSnapshotChecksum(full)
-	if err != nil {
-		return err
-	}
-	if len(full.GetChecksum()) != sha256.Size || string(checksum[:]) != string(full.GetChecksum()) {
-		return ErrSnapshotChecksum
-	}
-	proxies, err := wireProxies(full.GetProxies())
-	if err != nil {
-		return err
-	}
-	envelope := snapshot.Envelope{
-		ClusterID: watcher.options.ClusterID, WorkerID: watcher.options.WorkerID,
-		Epoch: full.GetOwnershipEpoch(), Version: full.GetVersion(), Full: true, Proxies: proxies,
-	}
-	envelope.Checksum = snapshot.Checksum(proxies)
-	return watcher.store.Apply(envelope)
-}
-
-func workerSnapshotChecksum(full *controlplanev1.WorkerSnapshot) ([sha256.Size]byte, error) {
-	if full == nil {
-		return [sha256.Size]byte{}, ErrInvalidSnapshotWatcher
-	}
-	copy := proto.Clone(full).(*controlplanev1.WorkerSnapshot)
-	copy.Checksum = nil
-	encoded, err := proto.MarshalOptions{Deterministic: true}.Marshal(copy)
-	if err != nil {
-		return [sha256.Size]byte{}, fmt.Errorf("marshal worker snapshot: %w", err)
-	}
-	return sha256.Sum256(encoded), nil
-}
-
-func wireProxies(source []*controlplanev1.OwnedProxy) ([]proxyDomain.Proxy, error) {
-	proxies := make([]proxyDomain.Proxy, len(source))
-	for index, item := range source {
-		proxy, err := wireProxy(item)
-		if err != nil {
-			return nil, err
-		}
-		proxies[index] = proxy
-	}
-	return proxies, nil
-}
-
-func wireProxy(source *controlplanev1.OwnedProxy) (proxyDomain.Proxy, error) {
-	if source == nil || !workerruntime.ValidIdentifier(source.GetId()) || !workerruntime.ValidIdentifier(source.GetUpstream()) ||
-		source.GetHost() == "" || source.GetPort() == 0 || source.GetPort() > math.MaxUint16 || source.GetMaxConcurrency() == 0 {
-		return proxyDomain.Proxy{}, ErrInvalidSnapshotWatcher
-	}
-	scheme, ok := wireScheme(source.GetProtocol())
-	if !ok {
-		return proxyDomain.Proxy{}, ErrInvalidSnapshotWatcher
-	}
-	expiresAt, err := wireTimestamp(source.GetExpiresAt())
-	if err != nil {
-		return proxyDomain.Proxy{}, err
-	}
-	usableUntil, err := wireTimestamp(source.GetUsableUntil())
-	if err != nil {
-		return proxyDomain.Proxy{}, err
-	}
-	tags := make(map[string]string, len(source.GetTags()))
-	for key, value := range source.GetTags() {
-		tags[key] = value
-	}
-	return proxyDomain.Proxy{
-		ID: source.GetId(), Scheme: scheme, Host: source.GetHost(), Port: uint16(source.GetPort()),
-		Username: source.GetUsername(), CredentialVersion: source.GetCredentialVersion(), SecretRef: source.GetSecretRef(),
-		SourceUpstream: source.GetUpstream(), ExpiresAt: expiresAt, UsableUntil: usableUntil,
-		MaxConcurrency: int64(source.GetMaxConcurrency()), State: proxyDomain.StateAvailable, Tags: tags,
-	}, nil
-}
-
-func wireScheme(protocol controlplanev1.ProxyProtocol) (proxyDomain.Scheme, bool) {
-	switch protocol {
-	case controlplanev1.ProxyProtocol_PROXY_PROTOCOL_HTTP:
-		return proxyDomain.SchemeHTTP, true
-	case controlplanev1.ProxyProtocol_PROXY_PROTOCOL_HTTPS:
-		return proxyDomain.SchemeHTTPS, true
-	case controlplanev1.ProxyProtocol_PROXY_PROTOCOL_SOCKS5:
-		return proxyDomain.SchemeSOCKS5, true
-	default:
-		return "", false
-	}
-}
-
-func wireTimestamp(value *timestamppb.Timestamp) (*time.Time, error) {
-	if value == nil {
-		return nil, nil
-	}
-	if err := value.CheckValid(); err != nil {
-		return nil, ErrInvalidSnapshotWatcher
-	}
-	converted := value.AsTime().UTC()
-	return &converted, nil
-}
-
-type generatedSnapshotRPCClient struct {
-	client controlplanev1.WorkerControlPlaneClient
-}
-
-func NewGeneratedSnapshotRPCClient(client controlplanev1.WorkerControlPlaneClient) SnapshotRPCClient {
-	return generatedSnapshotRPCClient{client: client}
-}
-
-func (client generatedSnapshotRPCClient) Watch(ctx context.Context, request *controlplanev1.WatchSnapshotsRequest) (SnapshotStream, error) {
-	return client.client.WatchSnapshots(ctx, request, grpc.WaitForReady(true))
-}
-
-func (client generatedSnapshotRPCClient) Acknowledge(ctx context.Context, request *controlplanev1.AcknowledgeSnapshotRequest) (*emptypb.Empty, error) {
-	return client.client.AcknowledgeSnapshot(ctx, request, grpc.WaitForReady(true))
-}

internal/gateway/controlplane/watcher_test.go

@@ -1,97 +0,0 @@
-package controlplane
-
-import (
-	"context"
-	"crypto/sha256"
-	"io"
-	"testing"
-	"time"
-
-	controlplanev1 "proxy-pool/gen/controlplane/v1"
-	"proxy-pool/internal/gateway/snapshot"
-
-	"google.golang.org/protobuf/types/known/emptypb"
-	"google.golang.org/protobuf/types/known/timestamppb"
-)
-
-func TestSnapshotWatcherAppliesVerifiedFullSnapshotAndAcknowledges(t *testing.T) {
-	store := snapshot.NewStore("cluster-a", "worker-a")
-	full := &controlplanev1.WorkerSnapshot{
-		Version: 1, OwnershipEpoch: 7, GeneratedAt: timestamppb.New(time.Now()), ValidUntil: timestamppb.New(time.Now().Add(time.Minute)),
-		Proxies: []*controlplanev1.OwnedProxy{{
-			Id: "proxy-a", Upstream: "upstream-a", Protocol: controlplanev1.ProxyProtocol_PROXY_PROTOCOL_HTTP,
-			Host: "192.0.2.10", Port: 8080, MaxConcurrency: 3, ExpiresAt: timestamppb.New(time.Now().Add(time.Minute)),
-		}},
-	}
-	setSnapshotChecksum(t, full)
-	client := &snapshotClientStub{stream: &snapshotStreamStub{values: []*controlplanev1.SnapshotEnvelope{{Payload: &controlplanev1.SnapshotEnvelope_Full{Full: full}}}}}
-	watcher, err := NewSnapshotWatcher(client, store, SnapshotWatcherOptions{ClusterID: "cluster-a", WorkerID: "worker-a"})
-	if err != nil {
-		t.Fatalf("NewSnapshotWatcher(): %v", err)
-	}
-	if err := watcher.Watch(context.Background(), "session-a"); err != nil {
-		t.Fatalf("Watch(): %v", err)
-	}
-	view := store.Current()
-	if view == nil || view.Version != 1 || view.Epoch != 7 || len(view.Entries) != 1 || view.Entries[0].Proxy.ID != "proxy-a" {
-		t.Fatalf("snapshot view = %+v", view)
-	}
-	if client.watch.GetSessionId() != "session-a" || client.ack.GetVersion() != 1 || !client.ack.GetApplied() || string(client.ack.GetChecksum()) != string(full.GetChecksum()) {
-		t.Fatalf("watch=%+v ack=%+v", client.watch, client.ack)
-	}
-}
-
-func TestSnapshotWatcherRejectsChecksumAndAcknowledgesFailure(t *testing.T) {
-	store := snapshot.NewStore("cluster-a", "worker-a")
-	full := &controlplanev1.WorkerSnapshot{Version: 1, OwnershipEpoch: 7, Checksum: make([]byte, sha256.Size)}
-	client := &snapshotClientStub{stream: &snapshotStreamStub{values: []*controlplanev1.SnapshotEnvelope{{Payload: &controlplanev1.SnapshotEnvelope_Full{Full: full}}}}}
-	watcher, err := NewSnapshotWatcher(client, store, SnapshotWatcherOptions{ClusterID: "cluster-a", WorkerID: "worker-a"})
-	if err != nil {
-		t.Fatalf("NewSnapshotWatcher(): %v", err)
-	}
-	if err := watcher.Watch(context.Background(), "session-a"); err == nil {
-		t.Fatal("Watch() error = nil, want checksum rejection")
-	}
-	if client.ack == nil || client.ack.GetApplied() || client.ack.GetVersion() != 1 {
-		t.Fatalf("negative acknowledgement = %+v", client.ack)
-	}
-}
-
-type snapshotClientStub struct {
-	stream SnapshotStream
-	watch  *controlplanev1.WatchSnapshotsRequest
-	ack    *controlplanev1.AcknowledgeSnapshotRequest
-}
-
-func (client *snapshotClientStub) Watch(_ context.Context, request *controlplanev1.WatchSnapshotsRequest) (SnapshotStream, error) {
-	client.watch = request
-	return client.stream, nil
-}
-
-func (client *snapshotClientStub) Acknowledge(_ context.Context, acknowledgement *controlplanev1.AcknowledgeSnapshotRequest) (*emptypb.Empty, error) {
-	client.ack = acknowledgement
-	return &emptypb.Empty{}, nil
-}
-
-type snapshotStreamStub struct {
-	values []*controlplanev1.SnapshotEnvelope
-	index  int
-}
-
-func (stream *snapshotStreamStub) Recv() (*controlplanev1.SnapshotEnvelope, error) {
-	if stream.index >= len(stream.values) {
-		return nil, io.EOF
-	}
-	value := stream.values[stream.index]
-	stream.index++
-	return value, nil
-}
-
-func setSnapshotChecksum(t *testing.T, full *controlplanev1.WorkerSnapshot) {
-	t.Helper()
-	checksum, err := workerSnapshotChecksum(full)
-	if err != nil {
-		t.Fatalf("workerSnapshotChecksum(): %v", err)
-	}
-	full.Checksum = checksum[:]
-}