feat(store): add WaitForStoreVersion API to wait for cluster store replication up to target version

api/pb/machine.pb.go

@@ -570,8 +570,8 @@ type JoinClusterRequest struct {
 	// MTU of the WireGuard interface on this machine. The daemon auto-detects the optimal MTU if 0 or not set.
 	WireguardMtu int32 `protobuf:"varint,7,opt,name=wireguard_mtu,json=wireguardMtu,proto3" json:"wireguard_mtu,omitempty"`
 	// Cluster store version this machine must reach before participating.
-	// Per-actor vector (Corrosion actor UUID → max applied db_version).
-	MinStoreVersion map[string]int64 `protobuf:"bytes,6,rep,name=min_store_version,json=minStoreVersion,proto3" json:"min_store_version,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3"`
+	// Per-actor vector (Corrosion actor UUID → minimum required db_version).
+	MinStoreVersion map[string]uint64 `protobuf:"bytes,6,rep,name=min_store_version,json=minStoreVersion,proto3" json:"min_store_version,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3"`
 }
 
 func (x *JoinClusterRequest) Reset() {
@@ -634,7 +634,7 @@ func (x *JoinClusterRequest) GetWireguardMtu() int32 {
 	return 0
 }
 
-func (x *JoinClusterRequest) GetMinStoreVersion() map[string]int64 {
+func (x *JoinClusterRequest) GetMinStoreVersion() map[string]uint64 {
 	if x != nil {
 		return x.MinStoreVersion
 	}
@@ -698,9 +698,16 @@ type MachineDetails struct {
 	Machine  *MachineInfo `protobuf:"bytes,2,opt,name=machine,proto3" json:"machine,omitempty"`
 	// Round-trip times to other machines in the cluster, keyed by peer machine ID.
 	Rtts map[string]*RTTStats `protobuf:"bytes,4,rep,name=rtts,proto3" json:"rtts,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
-	// Current cluster store version observed on this machine.
-	// Per-actor vector (Corrosion actor UUID → max applied db_version) read from Corrosion crsql_db_versions.
-	StoreVersion map[string]int64 `protobuf:"bytes,5,rep,name=store_version,json=storeVersion,proto3" json:"store_version,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3"`
+	// Store replication progress observed on this machine.
+	// Maps each Corrosion actor UUID to its highest processed database version. Corrosion also counts versions whose
+	// changes were superseded and skipped. Versions at or below a reported version may still be missing or pending
+	// locally.
+	//
+	// Pass this vector to WaitForStoreVersion on another machine to wait for replication through these versions.
+	// See that RPC's data-availability limitations. To combine observations from several machines, take the maximum
+	// for each actor.
+	// Capturing this vector does not wait for replication or prevent further writes.
+	StoreVersion map[string]uint64 `protobuf:"bytes,5,rep,name=store_version,json=storeVersion,proto3" json:"store_version,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3"`
 }
 
 func (x *MachineDetails) Reset() {
@@ -756,13 +763,64 @@ func (x *MachineDetails) GetRtts() map[string]*RTTStats {
 	return nil
 }
 
-func (x *MachineDetails) GetStoreVersion() map[string]int64 {
+func (x *MachineDetails) GetStoreVersion() map[string]uint64 {
 	if x != nil {
 		return x.StoreVersion
 	}
 	return nil
 }
 
+type WaitForStoreVersionRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// Minimum database version to reach for each Corrosion actor UUID.
+	// Obtain a vector from InspectMachine. To combine several responses, take the maximum version for each actor.
+	// Actors omitted from this vector and versions above its targets are not awaited. An empty vector requires
+	// no replication. Unknown actors with positive targets remain pending until replication reaches them or the RPC ends.
+	MinVersion map[string]uint64 `protobuf:"bytes,1,rep,name=min_version,json=minVersion,proto3" json:"min_version,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"varint,2,opt,name=value,proto3"`
+}
+
+func (x *WaitForStoreVersionRequest) Reset() {
+	*x = WaitForStoreVersionRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_api_pb_machine_proto_msgTypes[10]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *WaitForStoreVersionRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*WaitForStoreVersionRequest) ProtoMessage() {}
+
+func (x *WaitForStoreVersionRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_api_pb_machine_proto_msgTypes[10]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use WaitForStoreVersionRequest.ProtoReflect.Descriptor instead.
+func (*WaitForStoreVersionRequest) Descriptor() ([]byte, []int) {
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{10}
+}
+
+func (x *WaitForStoreVersionRequest) GetMinVersion() map[string]uint64 {
+	if x != nil {
+		return x.MinVersion
+	}
+	return nil
+}
+
 type TokenResponse struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -774,7 +832,7 @@ type TokenResponse struct {
 func (x *TokenResponse) Reset() {
 	*x = TokenResponse{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[10]
+		mi := &file_api_pb_machine_proto_msgTypes[11]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -787,7 +845,7 @@ func (x *TokenResponse) String() string {
 func (*TokenResponse) ProtoMessage() {}
 
 func (x *TokenResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[10]
+	mi := &file_api_pb_machine_proto_msgTypes[11]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -800,7 +858,7 @@ func (x *TokenResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use TokenResponse.ProtoReflect.Descriptor instead.
 func (*TokenResponse) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{10}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{11}
 }
 
 func (x *TokenResponse) GetToken() string {
@@ -819,7 +877,7 @@ type ResetRequest struct {
 func (x *ResetRequest) Reset() {
 	*x = ResetRequest{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[11]
+		mi := &file_api_pb_machine_proto_msgTypes[12]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -832,7 +890,7 @@ func (x *ResetRequest) String() string {
 func (*ResetRequest) ProtoMessage() {}
 
 func (x *ResetRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[11]
+	mi := &file_api_pb_machine_proto_msgTypes[12]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -845,7 +903,7 @@ func (x *ResetRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use ResetRequest.ProtoReflect.Descriptor instead.
 func (*ResetRequest) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{11}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{12}
 }
 
 type Service struct {
@@ -862,7 +920,7 @@ type Service struct {
 func (x *Service) Reset() {
 	*x = Service{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[12]
+		mi := &file_api_pb_machine_proto_msgTypes[13]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -875,7 +933,7 @@ func (x *Service) String() string {
 func (*Service) ProtoMessage() {}
 
 func (x *Service) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[12]
+	mi := &file_api_pb_machine_proto_msgTypes[13]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -888,7 +946,7 @@ func (x *Service) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Service.ProtoReflect.Descriptor instead.
 func (*Service) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{12}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{13}
 }
 
 func (x *Service) GetId() string {
@@ -930,7 +988,7 @@ type InspectServiceRequest struct {
 func (x *InspectServiceRequest) Reset() {
 	*x = InspectServiceRequest{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[13]
+		mi := &file_api_pb_machine_proto_msgTypes[14]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -943,7 +1001,7 @@ func (x *InspectServiceRequest) String() string {
 func (*InspectServiceRequest) ProtoMessage() {}
 
 func (x *InspectServiceRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[13]
+	mi := &file_api_pb_machine_proto_msgTypes[14]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -956,7 +1014,7 @@ func (x *InspectServiceRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use InspectServiceRequest.ProtoReflect.Descriptor instead.
 func (*InspectServiceRequest) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{13}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{14}
 }
 
 func (x *InspectServiceRequest) GetId() string {
@@ -977,7 +1035,7 @@ type InspectServiceResponse struct {
 func (x *InspectServiceResponse) Reset() {
 	*x = InspectServiceResponse{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[14]
+		mi := &file_api_pb_machine_proto_msgTypes[15]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -990,7 +1048,7 @@ func (x *InspectServiceResponse) String() string {
 func (*InspectServiceResponse) ProtoMessage() {}
 
 func (x *InspectServiceResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[14]
+	mi := &file_api_pb_machine_proto_msgTypes[15]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1003,7 +1061,7 @@ func (x *InspectServiceResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use InspectServiceResponse.ProtoReflect.Descriptor instead.
 func (*InspectServiceResponse) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{14}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{15}
 }
 
 func (x *InspectServiceResponse) GetService() *Service {
@@ -1027,7 +1085,7 @@ type InspectWireGuardNetworkResponse struct {
 func (x *InspectWireGuardNetworkResponse) Reset() {
 	*x = InspectWireGuardNetworkResponse{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[15]
+		mi := &file_api_pb_machine_proto_msgTypes[16]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -1040,7 +1098,7 @@ func (x *InspectWireGuardNetworkResponse) String() string {
 func (*InspectWireGuardNetworkResponse) ProtoMessage() {}
 
 func (x *InspectWireGuardNetworkResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[15]
+	mi := &file_api_pb_machine_proto_msgTypes[16]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1053,7 +1111,7 @@ func (x *InspectWireGuardNetworkResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use InspectWireGuardNetworkResponse.ProtoReflect.Descriptor instead.
 func (*InspectWireGuardNetworkResponse) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{15}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{16}
 }
 
 func (x *InspectWireGuardNetworkResponse) GetInterfaceName() string {
@@ -1100,7 +1158,7 @@ type WireGuardPeer struct {
 func (x *WireGuardPeer) Reset() {
 	*x = WireGuardPeer{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[16]
+		mi := &file_api_pb_machine_proto_msgTypes[17]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -1113,7 +1171,7 @@ func (x *WireGuardPeer) String() string {
 func (*WireGuardPeer) ProtoMessage() {}
 
 func (x *WireGuardPeer) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[16]
+	mi := &file_api_pb_machine_proto_msgTypes[17]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1126,7 +1184,7 @@ func (x *WireGuardPeer) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use WireGuardPeer.ProtoReflect.Descriptor instead.
 func (*WireGuardPeer) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{16}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{17}
 }
 
 func (x *WireGuardPeer) GetPublicKey() []byte {
@@ -1183,7 +1241,7 @@ type RTTStats struct {
 func (x *RTTStats) Reset() {
 	*x = RTTStats{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[17]
+		mi := &file_api_pb_machine_proto_msgTypes[18]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -1196,7 +1254,7 @@ func (x *RTTStats) String() string {
 func (*RTTStats) ProtoMessage() {}
 
 func (x *RTTStats) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[17]
+	mi := &file_api_pb_machine_proto_msgTypes[18]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1209,7 +1267,7 @@ func (x *RTTStats) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RTTStats.ProtoReflect.Descriptor instead.
 func (*RTTStats) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{17}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{18}
 }
 
 func (x *RTTStats) GetMedian() *durationpb.Duration {
@@ -1239,7 +1297,7 @@ type Service_Container struct {
 func (x *Service_Container) Reset() {
 	*x = Service_Container{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_api_pb_machine_proto_msgTypes[21]
+		mi := &file_api_pb_machine_proto_msgTypes[23]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -1252,7 +1310,7 @@ func (x *Service_Container) String() string {
 func (*Service_Container) ProtoMessage() {}
 
 func (x *Service_Container) ProtoReflect() protoreflect.Message {
-	mi := &file_api_pb_machine_proto_msgTypes[21]
+	mi := &file_api_pb_machine_proto_msgTypes[23]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1265,7 +1323,7 @@ func (x *Service_Container) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Service_Container.ProtoReflect.Descriptor instead.
 func (*Service_Container) Descriptor() ([]byte, []int) {
-	return file_api_pb_machine_proto_rawDescGZIP(), []int{12, 0}
+	return file_api_pb_machine_proto_rawDescGZIP(), []int{13, 0}
 }
 
 func (x *Service_Container) GetMachineId() string {
@@ -1392,7 +1450,7 @@ var file_api_pb_machine_proto_rawDesc = []byte{
 	0x14, 0x4d, 0x69, 0x6e, 0x53, 0x74, 0x6f, 0x72, 0x65, 0x56, 0x65, 0x72, 0x73, 0x69, 0x6f, 0x6e,
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@@ -1420,7 +1478,18 @@ var file_api_pb_machine_proto_rawDesc = []byte{
 	0x11, 0x53, 0x74, 0x6f, 0x72, 0x65, 0x56, 0x65, 0x72, 0x73, 0x69, 0x6f, 0x6e, 0x45, 0x6e, 0x74,
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@@ -1478,7 +1547,7 @@ var file_api_pb_machine_proto_rawDesc = []byte{
 	0x12, 0x32, 0x0a, 0x07, 0x73, 0x74, 0x64, 0x5f, 0x64, 0x65, 0x76, 0x18, 0x02, 0x20, 0x01, 0x28,
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+	0x64, 0x44, 0x65, 0x76, 0x32, 0xad, 0x06, 0x0a, 0x07, 0x4d, 0x61, 0x63, 0x68, 0x69, 0x6e, 0x65,
 	0x12, 0x4d, 0x0a, 0x12, 0x43, 0x68, 0x65, 0x63, 0x6b, 0x50, 0x72, 0x65, 0x72, 0x65, 0x71, 0x75,
 	0x69, 0x73, 0x69, 0x74, 0x65, 0x73, 0x12, 0x16, 0x2e, 0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2e,
 	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x45, 0x6d, 0x70, 0x74, 0x79, 0x1a, 0x1f,
@@ -1503,7 +1572,12 @@ var file_api_pb_machine_proto_rawDesc = []byte{
 	0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e,
 	0x45, 0x6d, 0x70, 0x74, 0x79, 0x1a, 0x1b, 0x2e, 0x61, 0x70, 0x69, 0x2e, 0x49, 0x6e, 0x73, 0x70,
 	0x65, 0x63, 0x74, 0x4d, 0x61, 0x63, 0x68, 0x69, 0x6e, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e,
-	0x73, 0x65, 0x12, 0x46, 0x0a, 0x0d, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x4d, 0x61, 0x63, 0x68,
+	0x73, 0x65, 0x12, 0x4e, 0x0a, 0x13, 0x57, 0x61, 0x69, 0x74, 0x46, 0x6f, 0x72, 0x53, 0x74, 0x6f,
+	0x72, 0x65, 0x56, 0x65, 0x72, 0x73, 0x69, 0x6f, 0x6e, 0x12, 0x1f, 0x2e, 0x61, 0x70, 0x69, 0x2e,
+	0x57, 0x61, 0x69, 0x74, 0x46, 0x6f, 0x72, 0x53, 0x74, 0x6f, 0x72, 0x65, 0x56, 0x65, 0x72, 0x73,
+	0x69, 0x6f, 0x6e, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x16, 0x2e, 0x67, 0x6f, 0x6f,
+	0x67, 0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x45, 0x6d, 0x70,
+	0x74, 0x79, 0x12, 0x46, 0x0a, 0x0d, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x4d, 0x61, 0x63, 0x68,
 	0x69, 0x6e, 0x65, 0x12, 0x19, 0x2e, 0x61, 0x70, 0x69, 0x2e, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65,
 	0x4d, 0x61, 0x63, 0x68, 0x69, 0x6e, 0x65, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x1a,
 	0x2e, 0x61, 0x70, 0x69, 0x2e, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65, 0x4d, 0x61, 0x63, 0x68, 0x69,
@@ -1542,7 +1616,7 @@ func file_api_pb_machine_proto_rawDescGZIP() []byte {
 	return file_api_pb_machine_proto_rawDescData
 }
 
-var file_api_pb_machine_proto_msgTypes = make([]protoimpl.MessageInfo, 22)
+var file_api_pb_machine_proto_msgTypes = make([]protoimpl.MessageInfo, 24)
 var file_api_pb_machine_proto_goTypes = []any{
 	(*MachineInfo)(nil),                     // 0: api.MachineInfo
 	(*NetworkConfig)(nil),                   // 1: api.NetworkConfig
@@ -1554,83 +1628,88 @@ var file_api_pb_machine_proto_goTypes = []any{
 	(*JoinClusterRequest)(nil),              // 7: api.JoinClusterRequest
 	(*InspectMachineResponse)(nil),          // 8: api.InspectMachineResponse
 	(*MachineDetails)(nil),                  // 9: api.MachineDetails
-	(*TokenResponse)(nil),                   // 10: api.TokenResponse
-	(*ResetRequest)(nil),                    // 11: api.ResetRequest
-	(*Service)(nil),                         // 12: api.Service
-	(*InspectServiceRequest)(nil),           // 13: api.InspectServiceRequest
-	(*InspectServiceResponse)(nil),          // 14: api.InspectServiceResponse
-	(*InspectWireGuardNetworkResponse)(nil), // 15: api.InspectWireGuardNetworkResponse
-	(*WireGuardPeer)(nil),                   // 16: api.WireGuardPeer
-	(*RTTStats)(nil),                        // 17: api.RTTStats
-	nil,                                     // 18: api.JoinClusterRequest.MinStoreVersionEntry
-	nil,                                     // 19: api.MachineDetails.RttsEntry
-	nil,                                     // 20: api.MachineDetails.StoreVersionEntry
-	(*Service_Container)(nil),               // 21: api.Service.Container
-	(*IP)(nil),                              // 22: api.IP
-	(*IPPrefix)(nil),                        // 23: api.IPPrefix
-	(*IPPort)(nil),                          // 24: api.IPPort
-	(*Metadata)(nil),                        // 25: api.Metadata
-	(*timestamppb.Timestamp)(nil),           // 26: google.protobuf.Timestamp
-	(*durationpb.Duration)(nil),             // 27: google.protobuf.Duration
-	(*emptypb.Empty)(nil),                   // 28: google.protobuf.Empty
-	(*LogsRequest)(nil),                     // 29: api.LogsRequest
-	(*LogEntry)(nil),                        // 30: api.LogEntry
+	(*WaitForStoreVersionRequest)(nil),      // 10: api.WaitForStoreVersionRequest
+	(*TokenResponse)(nil),                   // 11: api.TokenResponse
+	(*ResetRequest)(nil),                    // 12: api.ResetRequest
+	(*Service)(nil),                         // 13: api.Service
+	(*InspectServiceRequest)(nil),           // 14: api.InspectServiceRequest
+	(*InspectServiceResponse)(nil),          // 15: api.InspectServiceResponse
+	(*InspectWireGuardNetworkResponse)(nil), // 16: api.InspectWireGuardNetworkResponse
+	(*WireGuardPeer)(nil),                   // 17: api.WireGuardPeer
+	(*RTTStats)(nil),                        // 18: api.RTTStats
+	nil,                                     // 19: api.JoinClusterRequest.MinStoreVersionEntry
+	nil,                                     // 20: api.MachineDetails.RttsEntry
+	nil,                                     // 21: api.MachineDetails.StoreVersionEntry
+	nil,                                     // 22: api.WaitForStoreVersionRequest.MinVersionEntry
+	(*Service_Container)(nil),               // 23: api.Service.Container
+	(*IP)(nil),                              // 24: api.IP
+	(*IPPrefix)(nil),                        // 25: api.IPPrefix
+	(*IPPort)(nil),                          // 26: api.IPPort
+	(*Metadata)(nil),                        // 27: api.Metadata
+	(*timestamppb.Timestamp)(nil),           // 28: google.protobuf.Timestamp
+	(*durationpb.Duration)(nil),             // 29: google.protobuf.Duration
+	(*emptypb.Empty)(nil),                   // 30: google.protobuf.Empty
+	(*LogsRequest)(nil),                     // 31: api.LogsRequest
+	(*LogEntry)(nil),                        // 32: api.LogEntry
 }
 var file_api_pb_machine_proto_depIdxs = []int32{
 	1,  // 0: api.MachineInfo.network:type_name -> api.NetworkConfig
-	22, // 1: api.MachineInfo.public_ip:type_name -> api.IP
-	23, // 2: api.NetworkConfig.subnet:type_name -> api.IPPrefix
-	22, // 3: api.NetworkConfig.management_ip:type_name -> api.IP
-	24, // 4: api.NetworkConfig.endpoints:type_name -> api.IPPort
-	22, // 5: api.UpdateMachineRequest.public_ip:type_name -> api.IP
-	24, // 6: api.UpdateMachineRequest.endpoints:type_name -> api.IPPort
+	24, // 1: api.MachineInfo.public_ip:type_name -> api.IP
+	25, // 2: api.NetworkConfig.subnet:type_name -> api.IPPrefix
+	24, // 3: api.NetworkConfig.management_ip:type_name -> api.IP
+	26, // 4: api.NetworkConfig.endpoints:type_name -> api.IPPort
+	24, // 5: api.UpdateMachineRequest.public_ip:type_name -> api.IP
+	26, // 6: api.UpdateMachineRequest.endpoints:type_name -> api.IPPort
 	0,  // 7: api.UpdateMachineResponse.machine:type_name -> api.MachineInfo
-	23, // 8: api.InitClusterRequest.network:type_name -> api.IPPrefix
-	22, // 9: api.InitClusterRequest.public_ip:type_name -> api.IP
-	24, // 10: api.InitClusterRequest.wireguard_endpoints:type_name -> api.IPPort
+	25, // 8: api.InitClusterRequest.network:type_name -> api.IPPrefix
+	24, // 9: api.InitClusterRequest.public_ip:type_name -> api.IP
+	26, // 10: api.InitClusterRequest.wireguard_endpoints:type_name -> api.IPPort
 	0,  // 11: api.InitClusterResponse.machine:type_name -> api.MachineInfo
 	0,  // 12: api.JoinClusterRequest.machine:type_name -> api.MachineInfo
 	0,  // 13: api.JoinClusterRequest.other_machines:type_name -> api.MachineInfo
-	18, // 14: api.JoinClusterRequest.min_store_version:type_name -> api.JoinClusterRequest.MinStoreVersionEntry
+	19, // 14: api.JoinClusterRequest.min_store_version:type_name -> api.JoinClusterRequest.MinStoreVersionEntry
 	9,  // 15: api.InspectMachineResponse.machines:type_name -> api.MachineDetails
-	25, // 16: api.MachineDetails.metadata:type_name -> api.Metadata
+	27, // 16: api.MachineDetails.metadata:type_name -> api.Metadata
 	0,  // 17: api.MachineDetails.machine:type_name -> api.MachineInfo
-	19, // 18: api.MachineDetails.rtts:type_name -> api.MachineDetails.RttsEntry
-	20, // 19: api.MachineDetails.store_version:type_name -> api.MachineDetails.StoreVersionEntry
-	21, // 20: api.Service.containers:type_name -> api.Service.Container
-	12, // 21: api.InspectServiceResponse.service:type_name -> api.Service
-	16, // 22: api.InspectWireGuardNetworkResponse.peers:type_name -> api.WireGuardPeer
-	26, // 23: api.WireGuardPeer.last_handshake_time:type_name -> google.protobuf.Timestamp
-	27, // 24: api.RTTStats.median:type_name -> google.protobuf.Duration
-	27, // 25: api.RTTStats.std_dev:type_name -> google.protobuf.Duration
-	17, // 26: api.MachineDetails.RttsEntry.value:type_name -> api.RTTStats
-	28, // 27: api.Machine.CheckPrerequisites:input_type -> google.protobuf.Empty
-	5,  // 28: api.Machine.InitCluster:input_type -> api.InitClusterRequest
-	7,  // 29: api.Machine.JoinCluster:input_type -> api.JoinClusterRequest
-	28, // 30: api.Machine.Token:input_type -> google.protobuf.Empty
-	28, // 31: api.Machine.Inspect:input_type -> google.protobuf.Empty
-	28, // 32: api.Machine.InspectMachine:input_type -> google.protobuf.Empty
-	2,  // 33: api.Machine.UpdateMachine:input_type -> api.UpdateMachineRequest
-	28, // 34: api.Machine.InspectWireGuardNetwork:input_type -> google.protobuf.Empty
-	11, // 35: api.Machine.Reset:input_type -> api.ResetRequest
-	13, // 36: api.Machine.InspectService:input_type -> api.InspectServiceRequest
-	29, // 37: api.Machine.MachineLogs:input_type -> api.LogsRequest
-	4,  // 38: api.Machine.CheckPrerequisites:output_type -> api.CheckPrerequisitesResponse
-	6,  // 39: api.Machine.InitCluster:output_type -> api.InitClusterResponse
-	28, // 40: api.Machine.JoinCluster:output_type -> google.protobuf.Empty
-	10, // 41: api.Machine.Token:output_type -> api.TokenResponse
-	0,  // 42: api.Machine.Inspect:output_type -> api.MachineInfo
-	8,  // 43: api.Machine.InspectMachine:output_type -> api.InspectMachineResponse
-	3,  // 44: api.Machine.UpdateMachine:output_type -> api.UpdateMachineResponse
-	15, // 45: api.Machine.InspectWireGuardNetwork:output_type -> api.InspectWireGuardNetworkResponse
-	28, // 46: api.Machine.Reset:output_type -> google.protobuf.Empty
-	14, // 47: api.Machine.InspectService:output_type -> api.InspectServiceResponse
-	30, // 48: api.Machine.MachineLogs:output_type -> api.LogEntry
-	38, // [38:49] is the sub-list for method output_type
-	27, // [27:38] is the sub-list for method input_type
-	27, // [27:27] is the sub-list for extension type_name
-	27, // [27:27] is the sub-list for extension extendee
-	0,  // [0:27] is the sub-list for field type_name
+	20, // 18: api.MachineDetails.rtts:type_name -> api.MachineDetails.RttsEntry
+	21, // 19: api.MachineDetails.store_version:type_name -> api.MachineDetails.StoreVersionEntry
+	22, // 20: api.WaitForStoreVersionRequest.min_version:type_name -> api.WaitForStoreVersionRequest.MinVersionEntry
+	23, // 21: api.Service.containers:type_name -> api.Service.Container
+	13, // 22: api.InspectServiceResponse.service:type_name -> api.Service
+	17, // 23: api.InspectWireGuardNetworkResponse.peers:type_name -> api.WireGuardPeer
+	28, // 24: api.WireGuardPeer.last_handshake_time:type_name -> google.protobuf.Timestamp
+	29, // 25: api.RTTStats.median:type_name -> google.protobuf.Duration
+	29, // 26: api.RTTStats.std_dev:type_name -> google.protobuf.Duration
+	18, // 27: api.MachineDetails.RttsEntry.value:type_name -> api.RTTStats
+	30, // 28: api.Machine.CheckPrerequisites:input_type -> google.protobuf.Empty
+	5,  // 29: api.Machine.InitCluster:input_type -> api.InitClusterRequest
+	7,  // 30: api.Machine.JoinCluster:input_type -> api.JoinClusterRequest
+	30, // 31: api.Machine.Token:input_type -> google.protobuf.Empty
+	30, // 32: api.Machine.Inspect:input_type -> google.protobuf.Empty
+	30, // 33: api.Machine.InspectMachine:input_type -> google.protobuf.Empty
+	10, // 34: api.Machine.WaitForStoreVersion:input_type -> api.WaitForStoreVersionRequest
+	2,  // 35: api.Machine.UpdateMachine:input_type -> api.UpdateMachineRequest
+	30, // 36: api.Machine.InspectWireGuardNetwork:input_type -> google.protobuf.Empty
+	12, // 37: api.Machine.Reset:input_type -> api.ResetRequest
+	14, // 38: api.Machine.InspectService:input_type -> api.InspectServiceRequest
+	31, // 39: api.Machine.MachineLogs:input_type -> api.LogsRequest
+	4,  // 40: api.Machine.CheckPrerequisites:output_type -> api.CheckPrerequisitesResponse
+	6,  // 41: api.Machine.InitCluster:output_type -> api.InitClusterResponse
+	30, // 42: api.Machine.JoinCluster:output_type -> google.protobuf.Empty
+	11, // 43: api.Machine.Token:output_type -> api.TokenResponse
+	0,  // 44: api.Machine.Inspect:output_type -> api.MachineInfo
+	8,  // 45: api.Machine.InspectMachine:output_type -> api.InspectMachineResponse
+	30, // 46: api.Machine.WaitForStoreVersion:output_type -> google.protobuf.Empty
+	3,  // 47: api.Machine.UpdateMachine:output_type -> api.UpdateMachineResponse
+	16, // 48: api.Machine.InspectWireGuardNetwork:output_type -> api.InspectWireGuardNetworkResponse
+	30, // 49: api.Machine.Reset:output_type -> google.protobuf.Empty
+	15, // 50: api.Machine.InspectService:output_type -> api.InspectServiceResponse
+	32, // 51: api.Machine.MachineLogs:output_type -> api.LogEntry
+	40, // [40:52] is the sub-list for method output_type
+	28, // [28:40] is the sub-list for method input_type
+	28, // [28:28] is the sub-list for extension type_name
+	28, // [28:28] is the sub-list for extension extendee
+	0,  // [0:28] is the sub-list for field type_name
 }
 
 func init() { file_api_pb_machine_proto_init() }
@@ -1761,7 +1840,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[10].Exporter = func(v any, i int) any {
-			switch v := v.(*TokenResponse); i {
+			switch v := v.(*WaitForStoreVersionRequest); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1773,7 +1852,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[11].Exporter = func(v any, i int) any {
-			switch v := v.(*ResetRequest); i {
+			switch v := v.(*TokenResponse); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1785,7 +1864,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[12].Exporter = func(v any, i int) any {
-			switch v := v.(*Service); i {
+			switch v := v.(*ResetRequest); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1797,7 +1876,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[13].Exporter = func(v any, i int) any {
-			switch v := v.(*InspectServiceRequest); i {
+			switch v := v.(*Service); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1809,7 +1888,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[14].Exporter = func(v any, i int) any {
-			switch v := v.(*InspectServiceResponse); i {
+			switch v := v.(*InspectServiceRequest); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1821,7 +1900,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[15].Exporter = func(v any, i int) any {
-			switch v := v.(*InspectWireGuardNetworkResponse); i {
+			switch v := v.(*InspectServiceResponse); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1833,7 +1912,7 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[16].Exporter = func(v any, i int) any {
-			switch v := v.(*WireGuardPeer); i {
+			switch v := v.(*InspectWireGuardNetworkResponse); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -1845,6 +1924,18 @@ func file_api_pb_machine_proto_init() {
 			}
 		}
 		file_api_pb_machine_proto_msgTypes[17].Exporter = func(v any, i int) any {
+			switch v := v.(*WireGuardPeer); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_api_pb_machine_proto_msgTypes[18].Exporter = func(v any, i int) any {
 			switch v := v.(*RTTStats); i {
 			case 0:
 				return &v.state
@@ -1856,7 +1947,7 @@ func file_api_pb_machine_proto_init() {
 				return nil
 			}
 		}
-		file_api_pb_machine_proto_msgTypes[21].Exporter = func(v any, i int) any {
+		file_api_pb_machine_proto_msgTypes[23].Exporter = func(v any, i int) any {
 			switch v := v.(*Service_Container); i {
 			case 0:
 				return &v.state
@@ -1880,7 +1971,7 @@ func file_api_pb_machine_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_api_pb_machine_proto_rawDesc,
 			NumEnums:      0,
-			NumMessages:   22,
+			NumMessages:   24,
 			NumExtensions: 0,
 			NumServices:   1,
 		},

api/pb/machine.proto

@@ -19,6 +19,22 @@ service Machine {
   rpc Inspect(google.protobuf.Empty) returns (MachineInfo);
   // InspectMachine retrieves detailed information about the machine. Supports broadcasting to multiple machines.
   rpc InspectMachine(google.protobuf.Empty) returns (InspectMachineResponse);
+  // WaitForStoreVersion waits until the cluster store on this machine has reached each requested actor version, with
+  // no known missing or pending transactions through those versions.
+  // Corrosion may satisfy a version by applying its surviving changes or by marking it complete because its changes
+  // have been superseded.
+  //
+  // Waiting normally makes the captured data available on this machine. However, another write may replace some of that
+  // data before it arrives. Corrosion can then complete the older version without transferring the replaced data.
+  // If the replacement is outside the requested versions, this RPC can succeed while the affected data is still missing
+  // or outdated. This can happen during concurrent updates even when all machines are well connected.
+  //
+  // Success does not guarantee an exact snapshot or delivery of every historical value. Callers that require a specific
+  // record or condition should verify it after waiting.
+  //
+  // This RPC observes native replication without initiating synchronisation.
+  // Use the RPC deadline to bound the wait.
+  rpc WaitForStoreVersion(WaitForStoreVersionRequest) returns (google.protobuf.Empty);
   // UpdateMachine updates the configuration of the machine.
   rpc UpdateMachine(UpdateMachineRequest) returns (UpdateMachineResponse);
   // InspectWireGuardNetwork retrieves the current WireGuard network configuration and peer status.
@@ -105,8 +121,8 @@ message JoinClusterRequest {
   // MTU of the WireGuard interface on this machine. The daemon auto-detects the optimal MTU if 0 or not set.
   int32 wireguard_mtu = 7;
   // Cluster store version this machine must reach before participating.
-  // Per-actor vector (Corrosion actor UUID → max applied db_version).
-  map<string, int64> min_store_version = 6;
+  // Per-actor vector (Corrosion actor UUID → minimum required db_version).
+  map<string, uint64> min_store_version = 6;
 }
 
 message InspectMachineResponse {
@@ -119,9 +135,24 @@ message MachineDetails {
   MachineInfo machine = 2;
   // Round-trip times to other machines in the cluster, keyed by peer machine ID.
   map<string, RTTStats> rtts = 4;
-  // Current cluster store version observed on this machine.
-  // Per-actor vector (Corrosion actor UUID → max applied db_version) read from Corrosion crsql_db_versions.
-  map<string, int64> store_version = 5;
+  // Store replication progress observed on this machine.
+  // Maps each Corrosion actor UUID to its highest processed database version. Corrosion also counts versions whose
+  // changes were superseded and skipped. Versions at or below a reported version may still be missing or pending
+  // locally.
+  //
+  // Pass this vector to WaitForStoreVersion on another machine to wait for replication through these versions.
+  // See that RPC's data-availability limitations. To combine observations from several machines, take the maximum
+  // for each actor.
+  // Capturing this vector does not wait for replication or prevent further writes.
+  map<string, uint64> store_version = 5;
+}
+
+message WaitForStoreVersionRequest {
+  // Minimum database version to reach for each Corrosion actor UUID.
+  // Obtain a vector from InspectMachine. To combine several responses, take the maximum version for each actor.
+  // Actors omitted from this vector and versions above its targets are not awaited. An empty vector requires
+  // no replication. Unknown actors with positive targets remain pending until replication reaches them or the RPC ends.
+  map<string, uint64> min_version = 1;
 }
 
 message TokenResponse {

api/pb/machine_grpc.pb.go

@@ -26,6 +26,7 @@ const (
 	Machine_Token_FullMethodName                   = "/api.Machine/Token"
 	Machine_Inspect_FullMethodName                 = "/api.Machine/Inspect"
 	Machine_InspectMachine_FullMethodName          = "/api.Machine/InspectMachine"
+	Machine_WaitForStoreVersion_FullMethodName     = "/api.Machine/WaitForStoreVersion"
 	Machine_UpdateMachine_FullMethodName           = "/api.Machine/UpdateMachine"
 	Machine_InspectWireGuardNetwork_FullMethodName = "/api.Machine/InspectWireGuardNetwork"
 	Machine_Reset_FullMethodName                   = "/api.Machine/Reset"
@@ -46,6 +47,22 @@ type MachineClient interface {
 	Inspect(ctx context.Context, in *emptypb.Empty, opts ...grpc.CallOption) (*MachineInfo, error)
 	// InspectMachine retrieves detailed information about the machine. Supports broadcasting to multiple machines.
 	InspectMachine(ctx context.Context, in *emptypb.Empty, opts ...grpc.CallOption) (*InspectMachineResponse, error)
+	// WaitForStoreVersion waits until the cluster store on this machine has reached each requested actor version, with
+	// no known missing or pending transactions through those versions.
+	// Corrosion may satisfy a version by applying its surviving changes or by marking it complete because its changes
+	// have been superseded.
+	//
+	// Waiting normally makes the captured data available on this machine. However, another write may replace some of that
+	// data before it arrives. Corrosion can then complete the older version without transferring the replaced data.
+	// If the replacement is outside the requested versions, this RPC can succeed while the affected data is still missing
+	// or outdated. This can happen during concurrent updates even when all machines are well connected.
+	//
+	// Success does not guarantee an exact snapshot or delivery of every historical value. Callers that require a specific
+	// record or condition should verify it after waiting.
+	//
+	// This RPC observes native replication without initiating synchronisation.
+	// Use the RPC deadline to bound the wait.
+	WaitForStoreVersion(ctx context.Context, in *WaitForStoreVersionRequest, opts ...grpc.CallOption) (*emptypb.Empty, error)
 	// UpdateMachine updates the configuration of the machine.
 	UpdateMachine(ctx context.Context, in *UpdateMachineRequest, opts ...grpc.CallOption) (*UpdateMachineResponse, error)
 	// InspectWireGuardNetwork retrieves the current WireGuard network configuration and peer status.
@@ -124,6 +141,16 @@ func (c *machineClient) InspectMachine(ctx context.Context, in *emptypb.Empty, o
 	return out, nil
 }
 
+func (c *machineClient) WaitForStoreVersion(ctx context.Context, in *WaitForStoreVersionRequest, opts ...grpc.CallOption) (*emptypb.Empty, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(emptypb.Empty)
+	err := c.cc.Invoke(ctx, Machine_WaitForStoreVersion_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 func (c *machineClient) UpdateMachine(ctx context.Context, in *UpdateMachineRequest, opts ...grpc.CallOption) (*UpdateMachineResponse, error) {
 	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
 	out := new(UpdateMachineResponse)
@@ -196,6 +223,22 @@ type MachineServer interface {
 	Inspect(context.Context, *emptypb.Empty) (*MachineInfo, error)
 	// InspectMachine retrieves detailed information about the machine. Supports broadcasting to multiple machines.
 	InspectMachine(context.Context, *emptypb.Empty) (*InspectMachineResponse, error)
+	// WaitForStoreVersion waits until the cluster store on this machine has reached each requested actor version, with
+	// no known missing or pending transactions through those versions.
+	// Corrosion may satisfy a version by applying its surviving changes or by marking it complete because its changes
+	// have been superseded.
+	//
+	// Waiting normally makes the captured data available on this machine. However, another write may replace some of that
+	// data before it arrives. Corrosion can then complete the older version without transferring the replaced data.
+	// If the replacement is outside the requested versions, this RPC can succeed while the affected data is still missing
+	// or outdated. This can happen during concurrent updates even when all machines are well connected.
+	//
+	// Success does not guarantee an exact snapshot or delivery of every historical value. Callers that require a specific
+	// record or condition should verify it after waiting.
+	//
+	// This RPC observes native replication without initiating synchronisation.
+	// Use the RPC deadline to bound the wait.
+	WaitForStoreVersion(context.Context, *WaitForStoreVersionRequest) (*emptypb.Empty, error)
 	// UpdateMachine updates the configuration of the machine.
 	UpdateMachine(context.Context, *UpdateMachineRequest) (*UpdateMachineResponse, error)
 	// InspectWireGuardNetwork retrieves the current WireGuard network configuration and peer status.
@@ -232,6 +275,9 @@ func (UnimplementedMachineServer) Inspect(context.Context, *emptypb.Empty) (*Mac
 func (UnimplementedMachineServer) InspectMachine(context.Context, *emptypb.Empty) (*InspectMachineResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method InspectMachine not implemented")
 }
+func (UnimplementedMachineServer) WaitForStoreVersion(context.Context, *WaitForStoreVersionRequest) (*emptypb.Empty, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method WaitForStoreVersion not implemented")
+}
 func (UnimplementedMachineServer) UpdateMachine(context.Context, *UpdateMachineRequest) (*UpdateMachineResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method UpdateMachine not implemented")
 }
@@ -376,6 +422,24 @@ func _Machine_InspectMachine_Handler(srv interface{}, ctx context.Context, dec f
 	return interceptor(ctx, in, info, handler)
 }
 
+func _Machine_WaitForStoreVersion_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(WaitForStoreVersionRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(MachineServer).WaitForStoreVersion(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: Machine_WaitForStoreVersion_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(MachineServer).WaitForStoreVersion(ctx, req.(*WaitForStoreVersionRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 func _Machine_UpdateMachine_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
 	in := new(UpdateMachineRequest)
 	if err := dec(in); err != nil {
@@ -490,6 +554,10 @@ var Machine_ServiceDesc = grpc.ServiceDesc{
 			MethodName: "InspectMachine",
 			Handler:    _Machine_InspectMachine_Handler,
 		},
+		{
+			MethodName: "WaitForStoreVersion",
+			Handler:    _Machine_WaitForStoreVersion_Handler,
+		},
 		{
 			MethodName: "UpdateMachine",
 			Handler:    _Machine_UpdateMachine_Handler,

internal/cli/cli.go

@@ -458,7 +458,7 @@ func (cli *CLI) AddMachine(ctx context.Context, opts AddMachineOptions) (_ *clie
 	}
 
 	// Snapshot the cluster store version so the new machine can catch up before participating.
-	var storeVersion map[string]int64
+	var storeVersion map[string]uint64
 	inspectResp, err = c.MachineClient.InspectMachine(ctx, &emptypb.Empty{})
 	if err != nil {
 		// TODO(lhf): remove Unimplemented check when v0.17.0 is released.

internal/machine/cluster.go

@@ -446,11 +446,11 @@ func (cc *clusterController) waitStoreSync(ctx context.Context) error {
 }
 
 // laggingActors returns target actors whose local version is below the required value, as [have, need].
-func laggingActors(local, target map[string]int64) map[string][2]int64 {
-	lagging := make(map[string][2]int64)
+func laggingActors(local, target map[string]uint64) map[string][2]uint64 {
+	lagging := make(map[string][2]uint64)
 	for actor, need := range target {
 		if have := local[actor]; have < need {
-			lagging[actor] = [2]int64{have, need}
+			lagging[actor] = [2]uint64{have, need}
 		}
 	}
 	return lagging

internal/machine/machine.go

@@ -1124,6 +1124,19 @@ func (m *Machine) InspectMachine(ctx context.Context, _ *emptypb.Empty) (*pb.Ins
 	}, nil
 }
 
+func (m *Machine) WaitForStoreVersion(ctx context.Context, req *pb.WaitForStoreVersionRequest) (*emptypb.Empty, error) {
+	if err := m.store.WaitForVersion(ctx, req.MinVersion); err != nil {
+		if ctx.Err() != nil {
+			return nil, status.FromContextError(ctx.Err()).Err()
+		}
+		if errors.Is(err, store.ErrInvalidStoreVersion) {
+			return nil, status.Error(codes.InvalidArgument, err.Error())
+		}
+		return nil, status.Error(codes.Internal, err.Error())
+	}
+	return &emptypb.Empty{}, nil
+}
+
 // UpdateMachine updates the configuration of this machine in its local state (the source of truth) and syncs
 // the result to the cluster store.
 func (m *Machine) UpdateMachine(ctx context.Context, req *pb.UpdateMachineRequest) (*pb.UpdateMachineResponse, error) {

internal/machine/state.go

@@ -29,9 +29,9 @@ type State struct {
 	// PublicIP is this machine's advertised public IP for ingress. Zero value if unset.
 	PublicIP netip.Addr `json:",omitempty"`
 	// MinStoreVersion is the cluster store version this machine must reach before participating.
-	// Per-actor vector (Corrosion actor UUID → max applied db_version) captured from an existing
+	// Per-actor vector (Corrosion actor UUID → max processed db_version) captured from an existing
 	// member at join time. Cleared once reached.
-	MinStoreVersion map[string]int64 `json:",omitempty"`
+	MinStoreVersion map[string]uint64 `json:",omitempty"`
 	// CorrosionAPIToken authenticates requests to the local Corrosion API.
 	CorrosionAPIToken secret.Secret `json:",omitempty"`
 

internal/machine/store/replication.go

@@ -0,0 +1,106 @@
+package store
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+// ErrInvalidStoreVersion indicates an invalid actor UUID in a store version vector.
+var ErrInvalidStoreVersion = errors.New("invalid store version")
+
+// WaitForVersion waits until the local store has reached each actor's minimum version in minVersion, with no known
+// missing or pending transactions through those versions. Corrosion may satisfy a version by applying its surviving
+// changes or by marking it complete because its changes have been superseded.
+//
+// Waiting normally makes the captured data available locally. However, if another write replaces some of that data
+// before it arrives, Corrosion can complete the older version without transferring the replaced data. If the
+// replacement is outside minVersion, this method can return while the affected data is still missing or outdated.
+// This can happen during concurrent updates even when all machines are well connected.
+//
+// This method does not guarantee an exact snapshot or delivery of every historical value.
+// Callers that require a specific record or condition should verify it after waiting.
+//
+// The method observes native replication without initiating synchronisation.
+// An empty minVersion requires no replication. The context controls cancellation and the deadline.
+func (s *Store) WaitForVersion(ctx context.Context, minVersion map[string]uint64) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	placeholders := make([]string, 0, len(minVersion))
+	args := make([]any, 0, 2*len(minVersion))
+	for actor, version := range minVersion {
+		actorID, err := uuid.Parse(actor)
+		if err != nil {
+			return fmt.Errorf("%w: actor '%s' is not a UUID: %v", ErrInvalidStoreVersion, actor, err)
+		}
+		if version == 0 {
+			continue
+		}
+
+		// Corrosion accepts a JSON array of bytes as a BLOB parameter. A UUID marshals as a string,
+		// and a byte slice marshals as base64, so use a plain fixed-size array instead.
+		placeholders = append(placeholders, "(?, ?)")
+		args = append(args, [16]byte(actorID), version)
+	}
+	if len(args) == 0 {
+		return nil
+	}
+
+	// Check all bookkeeping in one SQLite snapshot. Raw buffered rows can remain after application,
+	// but sequence bookkeeping is removed in the same transaction that applies or clears a version.
+	query := `WITH min_version(actor_id, version) AS (VALUES ` + strings.Join(placeholders, ", ") + `)
+		SELECT NOT EXISTS (
+			SELECT 1 FROM min_version
+			LEFT JOIN crsql_db_versions AS current ON current.site_id = min_version.actor_id
+			WHERE COALESCE(current.db_version, 0) < min_version.version
+				OR EXISTS (
+					SELECT 1 FROM __corro_bookkeeping_gaps
+					WHERE actor_id = min_version.actor_id AND start <= min_version.version
+				)
+				OR EXISTS (
+					SELECT 1 FROM __corro_seq_bookkeeping
+					WHERE site_id = min_version.actor_id AND db_version <= min_version.version
+				)
+		)`
+
+	ticker := time.NewTicker(100 * time.Millisecond)
+	defer ticker.Stop()
+
+	for {
+		rows, err := s.corro.QueryContext(ctx, query, args...)
+		if err != nil {
+			return fmt.Errorf("check store replication: %w", err)
+		}
+		if !rows.Next() {
+			if err = rows.Err(); err != nil {
+				return fmt.Errorf("check store replication: %w", err)
+			}
+			return errors.New("check store replication: store version query returned no rows")
+		}
+		var reached int
+		if err = rows.Scan(&reached); err != nil {
+			rows.Close()
+			return fmt.Errorf("check store replication: %w", err)
+		}
+		rows.Next() // Consume the end-of-query event.
+		rows.Close()
+		if err = rows.Err(); err != nil {
+			return fmt.Errorf("check store replication: %w", err)
+		}
+		if reached == 1 {
+			return ctx.Err()
+		}
+
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-ticker.C:
+		}
+	}
+}

internal/machine/store/store.go

@@ -73,20 +73,27 @@ func (s *Store) Delete(ctx context.Context, key string) error {
 	return err
 }
 
-// Version returns the cluster store's per-actor version vector:
-// Corrosion actor ID (UUID string) → max received db_version for that actor.
-func (s *Store) Version(ctx context.Context) (map[string]int64, error) {
+// Version returns the replication progress observed by this store.
+// Each entry maps a Corrosion actor UUID to its highest processed database version. Corrosion also counts versions
+// whose changes were superseded and skipped. Versions at or below a reported version may still be missing or pending
+// locally.
+//
+// You can use [Store.WaitForVersion] to wait for replication through these versions, subject to the data-availability
+// limitations documented there.
+//
+// Capturing a vector does not wait for replication or prevent further writes.
+func (s *Store) Version(ctx context.Context) (map[string]uint64, error) {
 	rows, err := s.corro.QueryContext(ctx, "SELECT site_id, db_version FROM crsql_db_versions")
 	if err != nil {
 		return nil, fmt.Errorf("query crsql_db_versions: %w", err)
 	}
 	defer rows.Close()
 
-	versions := make(map[string]int64)
+	versions := make(map[string]uint64)
 	for rows.Next() {
 		var (
 			siteID  []byte
-			version int64
+			version uint64
 		)
 		if err = rows.Scan(&siteID, &version); err != nil {
 			return nil, fmt.Errorf("scan actor version: %w", err)
@@ -102,8 +109,8 @@ func (s *Store) Version(ctx context.Context) (map[string]int64, error) {
 
 type MissingChange struct {
 	ActorID      string
-	StartVersion int64
-	EndVersion   int64
+	StartVersion uint64
+	EndVersion   uint64
 }
 
 // KnownMissingChanges returns a list of currently known missing changes in the Corrosion database.