feat(distlock): refactor into a standalone package

pkg/distlock/doc.go

@@ -0,0 +1,7 @@
+// Package distlock provides distributed, automatically renewed leases across independent nodes.
+//
+// A Cluster must return every node in the lock group, including temporarily unavailable nodes, because every node
+// counts toward quorum. Changing the node set is unsafe if a new quorum can be disjoint from an earlier quorum while
+// leases acquired from the earlier node set may still be valid. Callers must stop protected work when the context
+// returned by Lease.Context is done.
+package distlock

pkg/distlock/grpc/lease.pb.go

@@ -0,0 +1,547 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.34.2
+// 	protoc        v5.27.3
+// source: pkg/distlock/grpc/lease.proto
+
+package grpc
+
+import (
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	durationpb "google.golang.org/protobuf/types/known/durationpb"
+	reflect "reflect"
+	sync "sync"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+type AcquireLeaseRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Resource string `protobuf:"bytes,1,opt,name=resource,proto3" json:"resource,omitempty"`
+	// Token uniquely identifies the lease owner.
+	Token []byte `protobuf:"bytes,2,opt,name=token,proto3" json:"token,omitempty"`
+	// TTL sets how long the lease remains valid without renewal.
+	Ttl *durationpb.Duration `protobuf:"bytes,3,opt,name=ttl,proto3" json:"ttl,omitempty"`
+}
+
+func (x *AcquireLeaseRequest) Reset() {
+	*x = AcquireLeaseRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[0]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *AcquireLeaseRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*AcquireLeaseRequest) ProtoMessage() {}
+
+func (x *AcquireLeaseRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[0]
+	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 AcquireLeaseRequest.ProtoReflect.Descriptor instead.
+func (*AcquireLeaseRequest) Descriptor() ([]byte, []int) {
+	return file_pkg_distlock_grpc_lease_proto_rawDescGZIP(), []int{0}
+}
+
+func (x *AcquireLeaseRequest) GetResource() string {
+	if x != nil {
+		return x.Resource
+	}
+	return ""
+}
+
+func (x *AcquireLeaseRequest) GetToken() []byte {
+	if x != nil {
+		return x.Token
+	}
+	return nil
+}
+
+func (x *AcquireLeaseRequest) GetTtl() *durationpb.Duration {
+	if x != nil {
+		return x.Ttl
+	}
+	return nil
+}
+
+type AcquireLeaseResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// Acquired is true when this request successfully created the lease.
+	Acquired bool `protobuf:"varint,1,opt,name=acquired,proto3" json:"acquired,omitempty"`
+}
+
+func (x *AcquireLeaseResponse) Reset() {
+	*x = AcquireLeaseResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[1]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *AcquireLeaseResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*AcquireLeaseResponse) ProtoMessage() {}
+
+func (x *AcquireLeaseResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[1]
+	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 AcquireLeaseResponse.ProtoReflect.Descriptor instead.
+func (*AcquireLeaseResponse) Descriptor() ([]byte, []int) {
+	return file_pkg_distlock_grpc_lease_proto_rawDescGZIP(), []int{1}
+}
+
+func (x *AcquireLeaseResponse) GetAcquired() bool {
+	if x != nil {
+		return x.Acquired
+	}
+	return false
+}
+
+type RenewLeaseRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Resource string `protobuf:"bytes,1,opt,name=resource,proto3" json:"resource,omitempty"`
+	// Token identifies the owner of the existing lease.
+	Token []byte `protobuf:"bytes,2,opt,name=token,proto3" json:"token,omitempty"`
+	// TTL sets how long the renewed lease remains valid.
+	Ttl *durationpb.Duration `protobuf:"bytes,3,opt,name=ttl,proto3" json:"ttl,omitempty"`
+}
+
+func (x *RenewLeaseRequest) Reset() {
+	*x = RenewLeaseRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[2]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *RenewLeaseRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*RenewLeaseRequest) ProtoMessage() {}
+
+func (x *RenewLeaseRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[2]
+	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 RenewLeaseRequest.ProtoReflect.Descriptor instead.
+func (*RenewLeaseRequest) Descriptor() ([]byte, []int) {
+	return file_pkg_distlock_grpc_lease_proto_rawDescGZIP(), []int{2}
+}
+
+func (x *RenewLeaseRequest) GetResource() string {
+	if x != nil {
+		return x.Resource
+	}
+	return ""
+}
+
+func (x *RenewLeaseRequest) GetToken() []byte {
+	if x != nil {
+		return x.Token
+	}
+	return nil
+}
+
+func (x *RenewLeaseRequest) GetTtl() *durationpb.Duration {
+	if x != nil {
+		return x.Ttl
+	}
+	return nil
+}
+
+type RenewLeaseResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// Renewed is true when an unexpired lease matched the ownership token and was successfully renewed.
+	Renewed bool `protobuf:"varint,1,opt,name=renewed,proto3" json:"renewed,omitempty"`
+}
+
+func (x *RenewLeaseResponse) Reset() {
+	*x = RenewLeaseResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[3]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *RenewLeaseResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*RenewLeaseResponse) ProtoMessage() {}
+
+func (x *RenewLeaseResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[3]
+	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 RenewLeaseResponse.ProtoReflect.Descriptor instead.
+func (*RenewLeaseResponse) Descriptor() ([]byte, []int) {
+	return file_pkg_distlock_grpc_lease_proto_rawDescGZIP(), []int{3}
+}
+
+func (x *RenewLeaseResponse) GetRenewed() bool {
+	if x != nil {
+		return x.Renewed
+	}
+	return false
+}
+
+type ReleaseLeaseRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Resource string `protobuf:"bytes,1,opt,name=resource,proto3" json:"resource,omitempty"`
+	// Token identifies the owner of the existing lease.
+	Token []byte `protobuf:"bytes,2,opt,name=token,proto3" json:"token,omitempty"`
+}
+
+func (x *ReleaseLeaseRequest) Reset() {
+	*x = ReleaseLeaseRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[4]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *ReleaseLeaseRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*ReleaseLeaseRequest) ProtoMessage() {}
+
+func (x *ReleaseLeaseRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[4]
+	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 ReleaseLeaseRequest.ProtoReflect.Descriptor instead.
+func (*ReleaseLeaseRequest) Descriptor() ([]byte, []int) {
+	return file_pkg_distlock_grpc_lease_proto_rawDescGZIP(), []int{4}
+}
+
+func (x *ReleaseLeaseRequest) GetResource() string {
+	if x != nil {
+		return x.Resource
+	}
+	return ""
+}
+
+func (x *ReleaseLeaseRequest) GetToken() []byte {
+	if x != nil {
+		return x.Token
+	}
+	return nil
+}
+
+type ReleaseLeaseResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// Released is true when an unexpired lease existed, matched the ownership token, and was successfully released.
+	Released bool `protobuf:"varint,1,opt,name=released,proto3" json:"released,omitempty"`
+}
+
+func (x *ReleaseLeaseResponse) Reset() {
+	*x = ReleaseLeaseResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[5]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *ReleaseLeaseResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*ReleaseLeaseResponse) ProtoMessage() {}
+
+func (x *ReleaseLeaseResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_pkg_distlock_grpc_lease_proto_msgTypes[5]
+	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 ReleaseLeaseResponse.ProtoReflect.Descriptor instead.
+func (*ReleaseLeaseResponse) Descriptor() ([]byte, []int) {
+	return file_pkg_distlock_grpc_lease_proto_rawDescGZIP(), []int{5}
+}
+
+func (x *ReleaseLeaseResponse) GetReleased() bool {
+	if x != nil {
+		return x.Released
+	}
+	return false
+}
+
+var File_pkg_distlock_grpc_lease_proto protoreflect.FileDescriptor
+
+var file_pkg_distlock_grpc_lease_proto_rawDesc = []byte{
+	0x0a, 0x1d, 0x70, 0x6b, 0x67, 0x2f, 0x64, 0x69, 0x73, 0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2f, 0x67,
+	0x72, 0x70, 0x63, 0x2f, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12,
+	0x0b, 0x64, 0x69, 0x73, 0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2e, 0x76, 0x31, 0x1a, 0x1e, 0x67, 0x6f,
+	0x6f, 0x67, 0x6c, 0x65, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2f, 0x64, 0x75,
+	0x72, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0x74, 0x0a, 0x13,
+	0x41, 0x63, 0x71, 0x75, 0x69, 0x72, 0x65, 0x4c, 0x65, 0x61, 0x73, 0x65, 0x52, 0x65, 0x71, 0x75,
+	0x65, 0x73, 0x74, 0x12, 0x1a, 0x0a, 0x08, 0x72, 0x65, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x18,
+	0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x08, 0x72, 0x65, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x12,
+	0x14, 0x0a, 0x05, 0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x05,
+	0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x12, 0x2b, 0x0a, 0x03, 0x74, 0x74, 0x6c, 0x18, 0x03, 0x20, 0x01,
+	0x28, 0x0b, 0x32, 0x19, 0x2e, 0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74,
+	0x6f, 0x62, 0x75, 0x66, 0x2e, 0x44, 0x75, 0x72, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x03, 0x74,
+	0x74, 0x6c, 0x22, 0x32, 0x0a, 0x14, 0x41, 0x63, 0x71, 0x75, 0x69, 0x72, 0x65, 0x4c, 0x65, 0x61,
+	0x73, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x1a, 0x0a, 0x08, 0x61, 0x63,
+	0x71, 0x75, 0x69, 0x72, 0x65, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x08, 0x52, 0x08, 0x61, 0x63,
+	0x71, 0x75, 0x69, 0x72, 0x65, 0x64, 0x22, 0x72, 0x0a, 0x11, 0x52, 0x65, 0x6e, 0x65, 0x77, 0x4c,
+	0x65, 0x61, 0x73, 0x65, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12, 0x1a, 0x0a, 0x08, 0x72,
+	0x65, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x08, 0x72,
+	0x65, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x12, 0x14, 0x0a, 0x05, 0x74, 0x6f, 0x6b, 0x65, 0x6e,
+	0x18, 0x02, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x05, 0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x12, 0x2b, 0x0a,
+	0x03, 0x74, 0x74, 0x6c, 0x18, 0x03, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x19, 0x2e, 0x67, 0x6f, 0x6f,
+	0x67, 0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x44, 0x75, 0x72,
+	0x61, 0x74, 0x69, 0x6f, 0x6e, 0x52, 0x03, 0x74, 0x74, 0x6c, 0x22, 0x2e, 0x0a, 0x12, 0x52, 0x65,
+	0x6e, 0x65, 0x77, 0x4c, 0x65, 0x61, 0x73, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65,
+	0x12, 0x18, 0x0a, 0x07, 0x72, 0x65, 0x6e, 0x65, 0x77, 0x65, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28,
+	0x08, 0x52, 0x07, 0x72, 0x65, 0x6e, 0x65, 0x77, 0x65, 0x64, 0x22, 0x47, 0x0a, 0x13, 0x52, 0x65,
+	0x6c, 0x65, 0x61, 0x73, 0x65, 0x4c, 0x65, 0x61, 0x73, 0x65, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73,
+	0x74, 0x12, 0x1a, 0x0a, 0x08, 0x72, 0x65, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x18, 0x01, 0x20,
+	0x01, 0x28, 0x09, 0x52, 0x08, 0x72, 0x65, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x12, 0x14, 0x0a,
+	0x05, 0x74, 0x6f, 0x6b, 0x65, 0x6e, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x05, 0x74, 0x6f,
+	0x6b, 0x65, 0x6e, 0x22, 0x32, 0x0a, 0x14, 0x52, 0x65, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x4c, 0x65,
+	0x61, 0x73, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x1a, 0x0a, 0x08, 0x72,
+	0x65, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x08, 0x52, 0x08, 0x72,
+	0x65, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x64, 0x32, 0xf1, 0x01, 0x0a, 0x05, 0x4c, 0x65, 0x61, 0x73,
+	0x65, 0x12, 0x4e, 0x0a, 0x07, 0x41, 0x63, 0x71, 0x75, 0x69, 0x72, 0x65, 0x12, 0x20, 0x2e, 0x64,
+	0x69, 0x73, 0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2e, 0x76, 0x31, 0x2e, 0x41, 0x63, 0x71, 0x75, 0x69,
+	0x72, 0x65, 0x4c, 0x65, 0x61, 0x73, 0x65, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x21,
+	0x2e, 0x64, 0x69, 0x73, 0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2e, 0x76, 0x31, 0x2e, 0x41, 0x63, 0x71,
+	0x75, 0x69, 0x72, 0x65, 0x4c, 0x65, 0x61, 0x73, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73,
+	0x65, 0x12, 0x48, 0x0a, 0x05, 0x52, 0x65, 0x6e, 0x65, 0x77, 0x12, 0x1e, 0x2e, 0x64, 0x69, 0x73,
+	0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2e, 0x76, 0x31, 0x2e, 0x52, 0x65, 0x6e, 0x65, 0x77, 0x4c, 0x65,
+	0x61, 0x73, 0x65, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x1f, 0x2e, 0x64, 0x69, 0x73,
+	0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2e, 0x76, 0x31, 0x2e, 0x52, 0x65, 0x6e, 0x65, 0x77, 0x4c, 0x65,
+	0x61, 0x73, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x4e, 0x0a, 0x07, 0x52,
+	0x65, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x12, 0x20, 0x2e, 0x64, 0x69, 0x73, 0x74, 0x6c, 0x6f, 0x63,
+	0x6b, 0x2e, 0x76, 0x31, 0x2e, 0x52, 0x65, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x4c, 0x65, 0x61, 0x73,
+	0x65, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x21, 0x2e, 0x64, 0x69, 0x73, 0x74, 0x6c,
+	0x6f, 0x63, 0x6b, 0x2e, 0x76, 0x31, 0x2e, 0x52, 0x65, 0x6c, 0x65, 0x61, 0x73, 0x65, 0x4c, 0x65,
+	0x61, 0x73, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x42, 0x31, 0x5a, 0x2f, 0x67,
+	0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x70, 0x73, 0x76, 0x69, 0x64, 0x65,
+	0x72, 0x73, 0x6b, 0x69, 0x2f, 0x75, 0x6e, 0x63, 0x6c, 0x6f, 0x75, 0x64, 0x2f, 0x70, 0x6b, 0x67,
+	0x2f, 0x64, 0x69, 0x73, 0x74, 0x6c, 0x6f, 0x63, 0x6b, 0x2f, 0x67, 0x72, 0x70, 0x63, 0x62, 0x06,
+	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+}
+
+var (
+	file_pkg_distlock_grpc_lease_proto_rawDescOnce sync.Once
+	file_pkg_distlock_grpc_lease_proto_rawDescData = file_pkg_distlock_grpc_lease_proto_rawDesc
+)
+
+func file_pkg_distlock_grpc_lease_proto_rawDescGZIP() []byte {
+	file_pkg_distlock_grpc_lease_proto_rawDescOnce.Do(func() {
+		file_pkg_distlock_grpc_lease_proto_rawDescData = protoimpl.X.CompressGZIP(file_pkg_distlock_grpc_lease_proto_rawDescData)
+	})
+	return file_pkg_distlock_grpc_lease_proto_rawDescData
+}
+
+var file_pkg_distlock_grpc_lease_proto_msgTypes = make([]protoimpl.MessageInfo, 6)
+var file_pkg_distlock_grpc_lease_proto_goTypes = []any{
+	(*AcquireLeaseRequest)(nil),  // 0: distlock.v1.AcquireLeaseRequest
+	(*AcquireLeaseResponse)(nil), // 1: distlock.v1.AcquireLeaseResponse
+	(*RenewLeaseRequest)(nil),    // 2: distlock.v1.RenewLeaseRequest
+	(*RenewLeaseResponse)(nil),   // 3: distlock.v1.RenewLeaseResponse
+	(*ReleaseLeaseRequest)(nil),  // 4: distlock.v1.ReleaseLeaseRequest
+	(*ReleaseLeaseResponse)(nil), // 5: distlock.v1.ReleaseLeaseResponse
+	(*durationpb.Duration)(nil),  // 6: google.protobuf.Duration
+}
+var file_pkg_distlock_grpc_lease_proto_depIdxs = []int32{
+	6, // 0: distlock.v1.AcquireLeaseRequest.ttl:type_name -> google.protobuf.Duration
+	6, // 1: distlock.v1.RenewLeaseRequest.ttl:type_name -> google.protobuf.Duration
+	0, // 2: distlock.v1.Lease.Acquire:input_type -> distlock.v1.AcquireLeaseRequest
+	2, // 3: distlock.v1.Lease.Renew:input_type -> distlock.v1.RenewLeaseRequest
+	4, // 4: distlock.v1.Lease.Release:input_type -> distlock.v1.ReleaseLeaseRequest
+	1, // 5: distlock.v1.Lease.Acquire:output_type -> distlock.v1.AcquireLeaseResponse
+	3, // 6: distlock.v1.Lease.Renew:output_type -> distlock.v1.RenewLeaseResponse
+	5, // 7: distlock.v1.Lease.Release:output_type -> distlock.v1.ReleaseLeaseResponse
+	5, // [5:8] is the sub-list for method output_type
+	2, // [2:5] is the sub-list for method input_type
+	2, // [2:2] is the sub-list for extension type_name
+	2, // [2:2] is the sub-list for extension extendee
+	0, // [0:2] is the sub-list for field type_name
+}
+
+func init() { file_pkg_distlock_grpc_lease_proto_init() }
+func file_pkg_distlock_grpc_lease_proto_init() {
+	if File_pkg_distlock_grpc_lease_proto != nil {
+		return
+	}
+	if !protoimpl.UnsafeEnabled {
+		file_pkg_distlock_grpc_lease_proto_msgTypes[0].Exporter = func(v any, i int) any {
+			switch v := v.(*AcquireLeaseRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_pkg_distlock_grpc_lease_proto_msgTypes[1].Exporter = func(v any, i int) any {
+			switch v := v.(*AcquireLeaseResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_pkg_distlock_grpc_lease_proto_msgTypes[2].Exporter = func(v any, i int) any {
+			switch v := v.(*RenewLeaseRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_pkg_distlock_grpc_lease_proto_msgTypes[3].Exporter = func(v any, i int) any {
+			switch v := v.(*RenewLeaseResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_pkg_distlock_grpc_lease_proto_msgTypes[4].Exporter = func(v any, i int) any {
+			switch v := v.(*ReleaseLeaseRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_pkg_distlock_grpc_lease_proto_msgTypes[5].Exporter = func(v any, i int) any {
+			switch v := v.(*ReleaseLeaseResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: file_pkg_distlock_grpc_lease_proto_rawDesc,
+			NumEnums:      0,
+			NumMessages:   6,
+			NumExtensions: 0,
+			NumServices:   1,
+		},
+		GoTypes:           file_pkg_distlock_grpc_lease_proto_goTypes,
+		DependencyIndexes: file_pkg_distlock_grpc_lease_proto_depIdxs,
+		MessageInfos:      file_pkg_distlock_grpc_lease_proto_msgTypes,
+	}.Build()
+	File_pkg_distlock_grpc_lease_proto = out.File
+	file_pkg_distlock_grpc_lease_proto_rawDesc = nil
+	file_pkg_distlock_grpc_lease_proto_goTypes = nil
+	file_pkg_distlock_grpc_lease_proto_depIdxs = nil
+}

pkg/distlock/grpc/lease.proto

@@ -0,0 +1,54 @@
+syntax = "proto3";
+
+package distlock.v1;
+
+option go_package = "github.com/psviderski/uncloud/pkg/distlock/grpc";
+
+import "google/protobuf/duration.proto";
+
+// Lease provides atomic operations for time-bound ownership of resources on one node.
+service Lease {
+  // Acquire creates a lease when the resource has no unexpired lease.
+  rpc Acquire(AcquireLeaseRequest) returns (AcquireLeaseResponse);
+  // Renew extends an unexpired lease when its ownership token matches.
+  rpc Renew(RenewLeaseRequest) returns (RenewLeaseResponse);
+  // Release removes an unexpired lease when its ownership token matches.
+  rpc Release(ReleaseLeaseRequest) returns (ReleaseLeaseResponse);
+}
+
+message AcquireLeaseRequest {
+  string resource = 1;
+  // Token uniquely identifies the lease owner.
+  bytes token = 2;
+  // TTL sets how long the lease remains valid without renewal.
+  google.protobuf.Duration ttl = 3;
+}
+
+message AcquireLeaseResponse {
+  // Acquired is true when this request successfully created the lease.
+  bool acquired = 1;
+}
+
+message RenewLeaseRequest {
+  string resource = 1;
+  // Token identifies the owner of the existing lease.
+  bytes token = 2;
+  // TTL sets how long the renewed lease remains valid.
+  google.protobuf.Duration ttl = 3;
+}
+
+message RenewLeaseResponse {
+  // Renewed is true when an unexpired lease matched the ownership token and was successfully renewed.
+  bool renewed = 1;
+}
+
+message ReleaseLeaseRequest {
+  string resource = 1;
+  // Token identifies the owner of the existing lease.
+  bytes token = 2;
+}
+
+message ReleaseLeaseResponse {
+  // Released is true when an unexpired lease existed, matched the ownership token, and was successfully released.
+  bool released = 1;
+}

pkg/distlock/grpc/lease_grpc.pb.go

@@ -0,0 +1,207 @@
+// Code generated by protoc-gen-go-grpc. DO NOT EDIT.
+// versions:
+// - protoc-gen-go-grpc v1.5.1
+// - protoc             v5.27.3
+// source: pkg/distlock/grpc/lease.proto
+
+package grpc
+
+import (
+	context "context"
+	grpc "google.golang.org/grpc"
+	codes "google.golang.org/grpc/codes"
+	status "google.golang.org/grpc/status"
+)
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+// Requires gRPC-Go v1.64.0 or later.
+const _ = grpc.SupportPackageIsVersion9
+
+const (
+	Lease_Acquire_FullMethodName = "/distlock.v1.Lease/Acquire"
+	Lease_Renew_FullMethodName   = "/distlock.v1.Lease/Renew"
+	Lease_Release_FullMethodName = "/distlock.v1.Lease/Release"
+)
+
+// LeaseClient is the client API for Lease service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://pkg.go.dev/google.golang.org/grpc/?tab=doc#ClientConn.NewStream.
+//
+// Lease provides atomic operations for time-bound ownership of resources on one node.
+type LeaseClient interface {
+	// Acquire creates a lease when the resource has no unexpired lease.
+	Acquire(ctx context.Context, in *AcquireLeaseRequest, opts ...grpc.CallOption) (*AcquireLeaseResponse, error)
+	// Renew extends an unexpired lease when its ownership token matches.
+	Renew(ctx context.Context, in *RenewLeaseRequest, opts ...grpc.CallOption) (*RenewLeaseResponse, error)
+	// Release removes an unexpired lease when its ownership token matches.
+	Release(ctx context.Context, in *ReleaseLeaseRequest, opts ...grpc.CallOption) (*ReleaseLeaseResponse, error)
+}
+
+type leaseClient struct {
+	cc grpc.ClientConnInterface
+}
+
+func NewLeaseClient(cc grpc.ClientConnInterface) LeaseClient {
+	return &leaseClient{cc}
+}
+
+func (c *leaseClient) Acquire(ctx context.Context, in *AcquireLeaseRequest, opts ...grpc.CallOption) (*AcquireLeaseResponse, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(AcquireLeaseResponse)
+	err := c.cc.Invoke(ctx, Lease_Acquire_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *leaseClient) Renew(ctx context.Context, in *RenewLeaseRequest, opts ...grpc.CallOption) (*RenewLeaseResponse, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(RenewLeaseResponse)
+	err := c.cc.Invoke(ctx, Lease_Renew_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *leaseClient) Release(ctx context.Context, in *ReleaseLeaseRequest, opts ...grpc.CallOption) (*ReleaseLeaseResponse, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(ReleaseLeaseResponse)
+	err := c.cc.Invoke(ctx, Lease_Release_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// LeaseServer is the server API for Lease service.
+// All implementations must embed UnimplementedLeaseServer
+// for forward compatibility.
+//
+// Lease provides atomic operations for time-bound ownership of resources on one node.
+type LeaseServer interface {
+	// Acquire creates a lease when the resource has no unexpired lease.
+	Acquire(context.Context, *AcquireLeaseRequest) (*AcquireLeaseResponse, error)
+	// Renew extends an unexpired lease when its ownership token matches.
+	Renew(context.Context, *RenewLeaseRequest) (*RenewLeaseResponse, error)
+	// Release removes an unexpired lease when its ownership token matches.
+	Release(context.Context, *ReleaseLeaseRequest) (*ReleaseLeaseResponse, error)
+	mustEmbedUnimplementedLeaseServer()
+}
+
+// UnimplementedLeaseServer must be embedded to have
+// forward compatible implementations.
+//
+// NOTE: this should be embedded by value instead of pointer to avoid a nil
+// pointer dereference when methods are called.
+type UnimplementedLeaseServer struct{}
+
+func (UnimplementedLeaseServer) Acquire(context.Context, *AcquireLeaseRequest) (*AcquireLeaseResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Acquire not implemented")
+}
+func (UnimplementedLeaseServer) Renew(context.Context, *RenewLeaseRequest) (*RenewLeaseResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Renew not implemented")
+}
+func (UnimplementedLeaseServer) Release(context.Context, *ReleaseLeaseRequest) (*ReleaseLeaseResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Release not implemented")
+}
+func (UnimplementedLeaseServer) mustEmbedUnimplementedLeaseServer() {}
+func (UnimplementedLeaseServer) testEmbeddedByValue()               {}
+
+// UnsafeLeaseServer may be embedded to opt out of forward compatibility for this service.
+// Use of this interface is not recommended, as added methods to LeaseServer will
+// result in compilation errors.
+type UnsafeLeaseServer interface {
+	mustEmbedUnimplementedLeaseServer()
+}
+
+func RegisterLeaseServer(s grpc.ServiceRegistrar, srv LeaseServer) {
+	// If the following call pancis, it indicates UnimplementedLeaseServer was
+	// embedded by pointer and is nil.  This will cause panics if an
+	// unimplemented method is ever invoked, so we test this at initialization
+	// time to prevent it from happening at runtime later due to I/O.
+	if t, ok := srv.(interface{ testEmbeddedByValue() }); ok {
+		t.testEmbeddedByValue()
+	}
+	s.RegisterService(&Lease_ServiceDesc, srv)
+}
+
+func _Lease_Acquire_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(AcquireLeaseRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(LeaseServer).Acquire(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: Lease_Acquire_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(LeaseServer).Acquire(ctx, req.(*AcquireLeaseRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Lease_Renew_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(RenewLeaseRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(LeaseServer).Renew(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: Lease_Renew_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(LeaseServer).Renew(ctx, req.(*RenewLeaseRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Lease_Release_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(ReleaseLeaseRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(LeaseServer).Release(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: Lease_Release_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(LeaseServer).Release(ctx, req.(*ReleaseLeaseRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+// Lease_ServiceDesc is the grpc.ServiceDesc for Lease service.
+// It's only intended for direct use with grpc.RegisterService,
+// and not to be introspected or modified (even as a copy)
+var Lease_ServiceDesc = grpc.ServiceDesc{
+	ServiceName: "distlock.v1.Lease",
+	HandlerType: (*LeaseServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "Acquire",
+			Handler:    _Lease_Acquire_Handler,
+		},
+		{
+			MethodName: "Renew",
+			Handler:    _Lease_Renew_Handler,
+		},
+		{
+			MethodName: "Release",
+			Handler:    _Lease_Release_Handler,
+		},
+	},
+	Streams:  []grpc.StreamDesc{},
+	Metadata: "pkg/distlock/grpc/lease.proto",
+}

pkg/distlock/grpc/server.go

@@ -0,0 +1,99 @@
+// Package grpc provides a gRPC transport for distlock node-local lease operations.
+package grpc
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/psviderski/uncloud/pkg/distlock"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/durationpb"
+)
+
+// Server adapts a node-local distlock.Store to the Lease gRPC service.
+type Server struct {
+	UnimplementedLeaseServer
+	store distlock.Store
+}
+
+// NewServer creates a node-local lease server.
+func NewServer(store distlock.Store) *Server {
+	return &Server{store: store}
+}
+
+// Acquire creates a lease when the resource has no unexpired lease.
+func (s *Server) Acquire(ctx context.Context, req *AcquireLeaseRequest) (*AcquireLeaseResponse, error) {
+	ttl, err := validateLeaseRequest(req.Resource, req.Token, req.Ttl)
+	if err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	acquired, err := s.store.Acquire(ctx, req.Resource, req.Token, ttl)
+	if err != nil {
+		return nil, storeStatusError(ctx, "acquire lease", err)
+	}
+	return &AcquireLeaseResponse{Acquired: acquired}, nil
+}
+
+// Renew extends an unexpired lease when its ownership token matches.
+func (s *Server) Renew(ctx context.Context, req *RenewLeaseRequest) (*RenewLeaseResponse, error) {
+	ttl, err := validateLeaseRequest(req.Resource, req.Token, req.Ttl)
+	if err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	renewed, err := s.store.Renew(ctx, req.Resource, req.Token, ttl)
+	if err != nil {
+		return nil, storeStatusError(ctx, "renew lease", err)
+	}
+	return &RenewLeaseResponse{Renewed: renewed}, nil
+}
+
+// Release removes an unexpired lease when its ownership token matches.
+func (s *Server) Release(ctx context.Context, req *ReleaseLeaseRequest) (*ReleaseLeaseResponse, error) {
+	if err := validateResourceToken(req.Resource, req.Token); err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	released, err := s.store.Release(ctx, req.Resource, req.Token)
+	if err != nil {
+		return nil, storeStatusError(ctx, "release lease", err)
+	}
+	return &ReleaseLeaseResponse{Released: released}, nil
+}
+
+func validateLeaseRequest(resource string, token []byte, ttl *durationpb.Duration) (time.Duration, error) {
+	if err := validateResourceToken(resource, token); err != nil {
+		return 0, err
+	}
+	if ttl == nil {
+		return 0, fmt.Errorf("TTL is not set")
+	}
+	if err := ttl.CheckValid(); err != nil {
+		return 0, fmt.Errorf("invalid TTL: %w", err)
+	}
+	duration := ttl.AsDuration()
+	if duration <= 0 {
+		return 0, fmt.Errorf("TTL must be positive")
+	}
+	return duration, nil
+}
+
+func validateResourceToken(resource string, token []byte) error {
+	if resource == "" {
+		return fmt.Errorf("resource is empty")
+	}
+	if len(token) == 0 {
+		return fmt.Errorf("token is empty")
+	}
+	return nil
+}
+
+func storeStatusError(ctx context.Context, operation string, err error) error {
+	if ctxErr := ctx.Err(); ctxErr != nil {
+		return status.FromContextError(ctxErr).Err()
+	}
+	return status.Error(codes.Internal, fmt.Sprintf("%s: %v", operation, err))
+}

pkg/distlock/memory.go

@@ -0,0 +1,139 @@
+package distlock
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"sync"
+	"time"
+)
+
+type memoryLease struct {
+	token     []byte
+	expiresAt time.Time
+}
+
+// MemoryStore stores leases in memory. Its contents are lost when the process exits.
+type MemoryStore struct {
+	mu     sync.Mutex
+	leases map[string]memoryLease
+	now    func() time.Time
+}
+
+// NewMemoryStore creates an empty in-memory lease store.
+func NewMemoryStore() *MemoryStore {
+	return &MemoryStore{
+		leases: make(map[string]memoryLease),
+		now:    time.Now,
+	}
+}
+
+// Acquire creates a lease when the resource does not have an unexpired lease.
+func (s *MemoryStore) Acquire(
+	ctx context.Context, resource string, token []byte, ttl time.Duration,
+) (bool, error) {
+	if err := validateStoreInput(ctx, resource, token, ttl); err != nil {
+		return false, err
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if err := ctx.Err(); err != nil {
+		return false, err
+	}
+	now := s.now()
+
+	if lease, ok := s.leases[resource]; ok && now.Before(lease.expiresAt) {
+		return false, nil
+	}
+
+	s.leases[resource] = memoryLease{
+		token:     bytes.Clone(token),
+		expiresAt: now.Add(ttl),
+	}
+	return true, nil
+}
+
+// Renew extends an unexpired lease when its ownership token matches.
+func (s *MemoryStore) Renew(
+	ctx context.Context, resource string, token []byte, ttl time.Duration,
+) (bool, error) {
+	if err := validateStoreInput(ctx, resource, token, ttl); err != nil {
+		return false, err
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if err := ctx.Err(); err != nil {
+		return false, err
+	}
+	now := s.now()
+
+	lease, ok := s.leases[resource]
+	if !ok {
+		return false, nil
+	}
+	if !now.Before(lease.expiresAt) {
+		delete(s.leases, resource)
+		return false, nil
+	}
+	if !bytes.Equal(lease.token, token) {
+		return false, nil
+	}
+
+	lease.expiresAt = now.Add(ttl)
+	s.leases[resource] = lease
+	return true, nil
+}
+
+// Release removes an unexpired lease when its ownership token matches.
+func (s *MemoryStore) Release(ctx context.Context, resource string, token []byte) (bool, error) {
+	if err := validateStoreResourceToken(ctx, resource, token); err != nil {
+		return false, err
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if err := ctx.Err(); err != nil {
+		return false, err
+	}
+	now := s.now()
+
+	lease, ok := s.leases[resource]
+	if !ok {
+		return false, nil
+	}
+	if !now.Before(lease.expiresAt) {
+		delete(s.leases, resource)
+		return false, nil
+	}
+	if !bytes.Equal(lease.token, token) {
+		return false, nil
+	}
+
+	delete(s.leases, resource)
+	return true, nil
+}
+
+func validateStoreInput(ctx context.Context, resource string, token []byte, ttl time.Duration) error {
+	if err := validateStoreResourceToken(ctx, resource, token); err != nil {
+		return err
+	}
+	if ttl <= 0 {
+		return fmt.Errorf("TTL must be positive")
+	}
+	return nil
+}
+
+func validateStoreResourceToken(ctx context.Context, resource string, token []byte) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if resource == "" {
+		return fmt.Errorf("resource is empty")
+	}
+	if len(token) == 0 {
+		return fmt.Errorf("token is empty")
+	}
+	return nil
+}

pkg/distlock/memory_test.go

@@ -0,0 +1,243 @@
+package distlock
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestMemoryStoreAcquire(t *testing.T) {
+	store := newTestMemoryStore()
+	ctx := context.Background()
+
+	acquired, err := store.Acquire(ctx, "resource-a", []byte("owner-a"), time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+
+	acquired, err = store.Acquire(ctx, "resource-a", []byte("owner-b"), time.Minute)
+	require.NoError(t, err)
+	require.False(t, acquired)
+
+	acquired, err = store.Acquire(ctx, "resource-b", []byte("owner-b"), time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+}
+
+func TestMemoryStoreExpirationAndStaleOwner(t *testing.T) {
+	now := time.Date(2026, time.August, 26, 12, 0, 0, 0, time.UTC)
+	store := newTestMemoryStore()
+	store.now = func() time.Time { return now }
+	ctx := context.Background()
+	oldToken := []byte("old-owner")
+	newToken := []byte("new-owner")
+
+	acquired, err := store.Acquire(ctx, "resource", oldToken, time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+
+	// A lease is expired at its expiration time, not only after it.
+	now = now.Add(time.Minute)
+	acquired, err = store.Acquire(ctx, "resource", newToken, time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+
+	released, err := store.Release(ctx, "resource", oldToken)
+	require.NoError(t, err)
+	require.False(t, released)
+
+	renewed, err := store.Renew(ctx, "resource", oldToken, time.Minute)
+	require.NoError(t, err)
+	require.False(t, renewed)
+
+	released, err = store.Release(ctx, "resource", newToken)
+	require.NoError(t, err)
+	require.True(t, released)
+}
+
+func TestMemoryStoreRenew(t *testing.T) {
+	now := time.Date(2026, time.August, 26, 12, 0, 0, 0, time.UTC)
+	store := newTestMemoryStore()
+	store.now = func() time.Time { return now }
+	ctx := context.Background()
+	token := []byte("owner")
+
+	acquired, err := store.Acquire(ctx, "resource", token, time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+
+	now = now.Add(30 * time.Second)
+	renewed, err := store.Renew(ctx, "resource", []byte("another-owner"), time.Minute)
+	require.NoError(t, err)
+	require.False(t, renewed)
+
+	renewed, err = store.Renew(ctx, "resource", token, time.Minute)
+	require.NoError(t, err)
+	require.True(t, renewed)
+
+	// The renewal extends the lease from the renewal time.
+	now = now.Add(30 * time.Second)
+	acquired, err = store.Acquire(ctx, "resource", []byte("another-owner"), time.Minute)
+	require.NoError(t, err)
+	require.False(t, acquired)
+
+	now = now.Add(30 * time.Second)
+	renewed, err = store.Renew(ctx, "resource", token, time.Minute)
+	require.NoError(t, err)
+	require.False(t, renewed)
+}
+
+func TestMemoryStoreRelease(t *testing.T) {
+	store := newTestMemoryStore()
+	ctx := context.Background()
+	token := []byte("owner")
+
+	released, err := store.Release(ctx, "resource", token)
+	require.NoError(t, err)
+	require.False(t, released)
+
+	acquired, err := store.Acquire(ctx, "resource", token, time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+
+	released, err = store.Release(ctx, "resource", []byte("another-owner"))
+	require.NoError(t, err)
+	require.False(t, released)
+
+	released, err = store.Release(ctx, "resource", token)
+	require.NoError(t, err)
+	require.True(t, released)
+
+	released, err = store.Release(ctx, "resource", token)
+	require.NoError(t, err)
+	require.False(t, released)
+}
+
+func TestMemoryStoreCopiesToken(t *testing.T) {
+	store := newTestMemoryStore()
+	ctx := context.Background()
+	token := []byte("owner")
+	originalToken := append([]byte(nil), token...)
+
+	acquired, err := store.Acquire(ctx, "resource", token, time.Minute)
+	require.NoError(t, err)
+	require.True(t, acquired)
+
+	token[0] = 'x'
+	released, err := store.Release(ctx, "resource", originalToken)
+	require.NoError(t, err)
+	require.True(t, released)
+}
+
+func TestMemoryStoreValidation(t *testing.T) {
+	tests := []struct {
+		name string
+		run  func(*MemoryStore) error
+	}{
+		{
+			name: "acquire with empty resource",
+			run: func(store *MemoryStore) error {
+				_, err := store.Acquire(context.Background(), "", []byte("owner"), time.Minute)
+				return err
+			},
+		},
+		{
+			name: "acquire with empty token",
+			run: func(store *MemoryStore) error {
+				_, err := store.Acquire(context.Background(), "resource", nil, time.Minute)
+				return err
+			},
+		},
+		{
+			name: "acquire with zero TTL",
+			run: func(store *MemoryStore) error {
+				_, err := store.Acquire(context.Background(), "resource", []byte("owner"), 0)
+				return err
+			},
+		},
+		{
+			name: "renew with negative TTL",
+			run: func(store *MemoryStore) error {
+				_, err := store.Renew(context.Background(), "resource", []byte("owner"), -time.Second)
+				return err
+			},
+		},
+		{
+			name: "release with empty token",
+			run: func(store *MemoryStore) error {
+				_, err := store.Release(context.Background(), "resource", nil)
+				return err
+			},
+		},
+		{
+			name: "cancelled context",
+			run: func(store *MemoryStore) error {
+				ctx, cancel := context.WithCancel(context.Background())
+				cancel()
+				_, err := store.Acquire(ctx, "resource", []byte("owner"), time.Minute)
+				return err
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			store := newTestMemoryStore()
+			require.Error(t, test.run(store))
+
+			// Invalid operations must not create or replace a lease.
+			acquired, err := store.Acquire(context.Background(), "resource", []byte("valid-owner"), time.Minute)
+			require.NoError(t, err)
+			require.True(t, acquired)
+		})
+	}
+}
+
+func TestMemoryStoreConcurrentAcquire(t *testing.T) {
+	const attempts = 100
+
+	store := newTestMemoryStore()
+	ctx := context.Background()
+	start := make(chan struct{})
+	errCh := make(chan error, attempts)
+	var acquired atomic.Int64
+	var wg sync.WaitGroup
+
+	for i := range attempts {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			<-start
+
+			ok, err := store.Acquire(ctx, "resource", []byte(fmt.Sprintf("owner-%d", i)), time.Minute)
+			if err != nil {
+				errCh <- err
+				return
+			}
+			if ok {
+				acquired.Add(1)
+			}
+		}()
+	}
+
+	close(start)
+	wg.Wait()
+	close(errCh)
+
+	for err := range errCh {
+		require.NoError(t, err)
+	}
+	require.EqualValues(t, 1, acquired.Load())
+}
+
+func newTestMemoryStore() *MemoryStore {
+	store := NewMemoryStore()
+	store.now = func() time.Time {
+		return time.Date(2026, time.August, 26, 12, 0, 0, 0, time.UTC)
+	}
+	return store
+}

pkg/distlock/store.go

@@ -0,0 +1,16 @@
+package distlock
+
+import (
+	"context"
+	"time"
+)
+
+// Store holds node-local lease state and provides atomic operations over it.
+type Store interface {
+	// Acquire creates a lease when the resource does not have an unexpired lease.
+	Acquire(ctx context.Context, resource string, token []byte, ttl time.Duration) (bool, error)
+	// Renew extends an unexpired lease when its ownership token matches.
+	Renew(ctx context.Context, resource string, token []byte, ttl time.Duration) (bool, error)
+	// Release removes a lease when its ownership token matches.
+	Release(ctx context.Context, resource string, token []byte) (bool, error)
+}