lease: modify API and persist lease to disk

lease/leasepb/lease.pb.go

@@ -0,0 +1,282 @@
+// Code generated by protoc-gen-gogo.
+// source: lease.proto
+// DO NOT EDIT!
+
+/*
+	Package leasepb is a generated protocol buffer package.
+
+	It is generated from these files:
+		lease.proto
+
+	It has these top-level messages:
+		Lease
+*/
+package leasepb
+
+import proto "github.com/coreos/etcd/Godeps/_workspace/src/github.com/gogo/protobuf/proto"
+
+// discarding unused import gogoproto "github.com/coreos/etcd/Godeps/_workspace/src/gogoproto"
+
+import io "io"
+import fmt "fmt"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+
+type Lease struct {
+	ID  int64 `protobuf:"varint,1,opt,proto3" json:"ID,omitempty"`
+	TTL int64 `protobuf:"varint,2,opt,proto3" json:"TTL,omitempty"`
+}
+
+func (m *Lease) Reset()         { *m = Lease{} }
+func (m *Lease) String() string { return proto.CompactTextString(m) }
+func (*Lease) ProtoMessage()    {}
+
+func (m *Lease) Marshal() (data []byte, err error) {
+	size := m.Size()
+	data = make([]byte, size)
+	n, err := m.MarshalTo(data)
+	if err != nil {
+		return nil, err
+	}
+	return data[:n], nil
+}
+
+func (m *Lease) MarshalTo(data []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.ID != 0 {
+		data[i] = 0x8
+		i++
+		i = encodeVarintLease(data, i, uint64(m.ID))
+	}
+	if m.TTL != 0 {
+		data[i] = 0x10
+		i++
+		i = encodeVarintLease(data, i, uint64(m.TTL))
+	}
+	return i, nil
+}
+
+func encodeFixed64Lease(data []byte, offset int, v uint64) int {
+	data[offset] = uint8(v)
+	data[offset+1] = uint8(v >> 8)
+	data[offset+2] = uint8(v >> 16)
+	data[offset+3] = uint8(v >> 24)
+	data[offset+4] = uint8(v >> 32)
+	data[offset+5] = uint8(v >> 40)
+	data[offset+6] = uint8(v >> 48)
+	data[offset+7] = uint8(v >> 56)
+	return offset + 8
+}
+func encodeFixed32Lease(data []byte, offset int, v uint32) int {
+	data[offset] = uint8(v)
+	data[offset+1] = uint8(v >> 8)
+	data[offset+2] = uint8(v >> 16)
+	data[offset+3] = uint8(v >> 24)
+	return offset + 4
+}
+func encodeVarintLease(data []byte, offset int, v uint64) int {
+	for v >= 1<<7 {
+		data[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	data[offset] = uint8(v)
+	return offset + 1
+}
+func (m *Lease) Size() (n int) {
+	var l int
+	_ = l
+	if m.ID != 0 {
+		n += 1 + sovLease(uint64(m.ID))
+	}
+	if m.TTL != 0 {
+		n += 1 + sovLease(uint64(m.TTL))
+	}
+	return n
+}
+
+func sovLease(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+func sozLease(x uint64) (n int) {
+	return sovLease(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Lease) Unmarshal(data []byte) error {
+	l := len(data)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := data[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field ID", wireType)
+			}
+			m.ID = 0
+			for shift := uint(0); ; shift += 7 {
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := data[iNdEx]
+				iNdEx++
+				m.ID |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field TTL", wireType)
+			}
+			m.TTL = 0
+			for shift := uint(0); ; shift += 7 {
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := data[iNdEx]
+				iNdEx++
+				m.TTL |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			var sizeOfWire int
+			for {
+				sizeOfWire++
+				wire >>= 7
+				if wire == 0 {
+					break
+				}
+			}
+			iNdEx -= sizeOfWire
+			skippy, err := skipLease(data[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	return nil
+}
+func skipLease(data []byte) (n int, err error) {
+	l := len(data)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := data[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for {
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if data[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+			return iNdEx, nil
+		case 1:
+			iNdEx += 8
+			return iNdEx, nil
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := data[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			iNdEx += length
+			if length < 0 {
+				return 0, ErrInvalidLengthLease
+			}
+			return iNdEx, nil
+		case 3:
+			for {
+				var innerWire uint64
+				var start int = iNdEx
+				for shift := uint(0); ; shift += 7 {
+					if iNdEx >= l {
+						return 0, io.ErrUnexpectedEOF
+					}
+					b := data[iNdEx]
+					iNdEx++
+					innerWire |= (uint64(b) & 0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				innerWireType := int(innerWire & 0x7)
+				if innerWireType == 4 {
+					break
+				}
+				next, err := skipLease(data[start:])
+				if err != nil {
+					return 0, err
+				}
+				iNdEx = start + next
+			}
+			return iNdEx, nil
+		case 4:
+			return iNdEx, nil
+		case 5:
+			iNdEx += 4
+			return iNdEx, nil
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+	}
+	panic("unreachable")
+}
+
+var (
+	ErrInvalidLengthLease = fmt.Errorf("proto: negative length found during unmarshaling")
+)

lease/leasepb/lease.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+package leasepb;
+
+import "gogoproto/gogo.proto";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.sizer_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+option (gogoproto.goproto_getters_all) = false;
+option (gogoproto.goproto_enum_prefix_all) = false;
+
+message Lease {
+  int64 ID = 1;
+  int64 TTL = 2;
+}

lease/lessor.go

@@ -15,15 +15,20 @@
 package lease
 
 import (
+	"encoding/binary"
 	"fmt"
 	"sync"
 	"time"
 
+	"github.com/coreos/etcd/lease/leasepb"
 	"github.com/coreos/etcd/pkg/idutil"
+	"github.com/coreos/etcd/storage/backend"
 )
 
 var (
 	minLeaseTerm = 5 * time.Second
+
+	leaseBucketName = []byte("lease")
 )
 
 // DeleteableRange defines an interface with DeleteRange method.
@@ -37,7 +42,6 @@ type DeleteableRange interface {
 
 // a lessor is the owner of leases. It can grant, revoke,
 // renew and modify leases for lessee.
-// TODO: persist lease on to stable backend for failure recovery.
 // TODO: use clockwork for testability.
 type lessor struct {
 	mu sync.Mutex
@@ -47,49 +51,67 @@ type lessor struct {
 	// We want to make Grant, Revoke, and FindExpired all O(logN) and
 	// Renew O(1).
 	// FindExpired and Renew should be the most frequent operations.
-	leaseMap map[uint64]*lease
+	leaseMap map[int64]*lease
 
 	// A DeleteableRange the lessor operates on.
 	// When a lease expires, the lessor will delete the
 	// leased range (or key) from the DeleteableRange.
 	dr DeleteableRange
 
+	// backend to persist leases. We only persist lease ID and expiry for now.
+	// The leased items can be recovered by iterating all the keys in kv.
+	b backend.Backend
+
 	idgen *idutil.Generator
 }
 
-func NewLessor(lessorID uint8, dr DeleteableRange) *lessor {
-	return &lessor{
-		leaseMap: make(map[uint64]*lease),
+func NewLessor(lessorID uint8, b backend.Backend, dr DeleteableRange) *lessor {
+	l := &lessor{
+		leaseMap: make(map[int64]*lease),
+		b:        b,
 		dr:       dr,
 		idgen:    idutil.NewGenerator(lessorID, time.Now()),
 	}
+
+	tx := l.b.BatchTx()
+	tx.Lock()
+	tx.UnsafeCreateBucket(leaseBucketName)
+	tx.Unlock()
+	l.b.ForceCommit()
+
+	// TODO: recover from previous state in backend.
+
+	return l
 }
 
-// Grant grants a lease that expires at least at the given expiry
-// time.
-// TODO: when leassor is under highload, it should give out lease
-// with longer term to reduce renew load.
-func (le *lessor) Grant(expiry time.Time) *lease {
+// Grant grants a lease that expires at least after TTL seconds.
+// TODO: when lessor is under high load, it should give out lease
+// with longer TTL to reduce renew load.
+func (le *lessor) Grant(ttl int64) *lease {
+	// TODO: define max TTL
+	expiry := time.Now().Add(time.Duration(ttl) * time.Second)
 	expiry = minExpiry(time.Now(), expiry)
 
-	id := le.idgen.Next()
+	id := int64(le.idgen.Next())
 
 	le.mu.Lock()
 	defer le.mu.Unlock()
 
-	l := &lease{id: id, expiry: expiry, itemSet: make(map[leaseItem]struct{})}
+	l := &lease{id: id, ttl: ttl, expiry: expiry, itemSet: make(map[leaseItem]struct{})}
 	if _, ok := le.leaseMap[id]; ok {
 		panic("lease: unexpected duplicate ID!")
 	}
 
 	le.leaseMap[id] = l
+	l.persistTo(le.b)
+
 	return l
 }
 
 // Revoke revokes a lease with given ID. The item attached to the
 // given lease will be removed. If the ID does not exist, an error
 // will be returned.
-func (le *lessor) Revoke(id uint64) error {
+func (le *lessor) Revoke(id int64) error {
 	le.mu.Lock()
 	defer le.mu.Unlock()
 
@@ -98,19 +120,20 @@ func (le *lessor) Revoke(id uint64) error {
 		return fmt.Errorf("lease: cannot find lease %x", id)
 	}
 
-	delete(le.leaseMap, l.id)
-
 	for item := range l.itemSet {
-		le.dr.DeleteRange([]byte(item.key), []byte(item.endRange))
+		le.dr.DeleteRange([]byte(item.key), nil)
 	}
 
+	delete(le.leaseMap, l.id)
+	l.removeFrom(le.b)
+
 	return nil
 }
 
-// Renew renews an existing lease with at least the given expiry.
-// If the given lease does not exist or has expired, an error will
-// be returned.
-func (le *lessor) Renew(id uint64, expiry time.Time) error {
+// Renew renews an existing lease. If the given lease does not exist or
+// has expired, an error will be returned.
+// TODO: return new TTL?
+func (le *lessor) Renew(id int64) error {
 	le.mu.Lock()
 	defer le.mu.Unlock()
 
@@ -119,6 +142,7 @@ func (le *lessor) Renew(id uint64, expiry time.Time) error {
 		return fmt.Errorf("lease: cannot find lease %x", id)
 	}
 
+	expiry := time.Now().Add(time.Duration(l.ttl) * time.Second)
 	l.expiry = minExpiry(time.Now(), expiry)
 	return nil
 }
@@ -126,7 +150,7 @@ func (le *lessor) Renew(id uint64, expiry time.Time) error {
 // Attach attaches items to the lease with given ID. When the lease
 // expires, the attached items will be automatically removed.
 // If the given lease does not exist, an error will be returned.
-func (le *lessor) Attach(id uint64, items []leaseItem) error {
+func (le *lessor) Attach(id int64, items []leaseItem) error {
 	le.mu.Lock()
 	defer le.mu.Unlock()
 
@@ -161,7 +185,7 @@ func (le *lessor) findExpiredLeases() []*lease {
 
 // get gets the lease with given id.
 // get is a helper fucntion for testing, at least for now.
-func (le *lessor) get(id uint64) *lease {
+func (le *lessor) get(id int64) *lease {
 	le.mu.Lock()
 	defer le.mu.Unlock()
 
@@ -169,16 +193,38 @@ func (le *lessor) get(id uint64) *lease {
 }
 
 type lease struct {
-	id uint64
+	id  int64
+	ttl int64 // time to live in seconds
 
 	itemSet map[leaseItem]struct{}
 	// expiry time in unixnano
 	expiry time.Time
 }
 
+func (l lease) persistTo(b backend.Backend) {
+	key := int64ToBytes(l.id)
+
+	lpb := leasepb.Lease{ID: l.id, TTL: int64(l.ttl)}
+	val, err := lpb.Marshal()
+	if err != nil {
+		panic("failed to marshal lease proto item")
+	}
+
+	b.BatchTx().Lock()
+	b.BatchTx().UnsafePut(leaseBucketName, key, val)
+	b.BatchTx().Unlock()
+}
+
+func (l lease) removeFrom(b backend.Backend) {
+	key := int64ToBytes(l.id)
+
+	b.BatchTx().Lock()
+	b.BatchTx().UnsafeDelete(leaseBucketName, key)
+	b.BatchTx().Unlock()
+}
+
 type leaseItem struct {
-	key      string
-	endRange string
+	key string
 }
 
 // minExpiry returns a minimal expiry. A minimal expiry is the larger on
@@ -190,3 +236,9 @@ func minExpiry(now time.Time, expectedExpiry time.Time) time.Time {
 	}
 	return expectedExpiry
 }
+
+func int64ToBytes(n int64) []byte {
+	bytes := make([]byte, 8)
+	binary.BigEndian.PutUint64(bytes, uint64(n))
+	return bytes
+}

lease/lessor_test.go

@@ -15,18 +15,27 @@
 package lease
 
 import (
+	"io/ioutil"
+	"os"
+	"path"
 	"reflect"
 	"testing"
 	"time"
+
+	"github.com/coreos/etcd/storage/backend"
 )
 
 // TestLessorGrant ensures Lessor can grant wanted lease.
 // The granted lease should have a unique ID with a term
 // that is greater than minLeaseTerm.
 func TestLessorGrant(t *testing.T) {
-	le := NewLessor(1, &fakeDeleteable{})
+	dir, be := NewTestBackend(t)
+	defer os.RemoveAll(dir)
+	defer be.Close()
 
-	l := le.Grant(time.Now().Add(time.Second))
+	le := NewLessor(1, be, &fakeDeleteable{})
+
+	l := le.Grant(1)
 	gl := le.get(l.id)
 
 	if !reflect.DeepEqual(gl, l) {
@@ -36,10 +45,17 @@ func TestLessorGrant(t *testing.T) {
 		t.Errorf("term = %v, want at least %v", l.expiry.Sub(time.Now()), minLeaseTerm-time.Second)
 	}
 
-	nl := le.Grant(time.Now().Add(time.Second))
+	nl := le.Grant(1)
 	if nl.id == l.id {
 		t.Errorf("new lease.id = %x, want != %x", nl.id, l.id)
 	}
+
+	be.BatchTx().Lock()
+	_, vs := be.BatchTx().UnsafeRange(leaseBucketName, int64ToBytes(l.id), nil, 0)
+	if len(vs) != 1 {
+		t.Errorf("len(vs) = %d, want 1", len(vs))
+	}
+	be.BatchTx().Unlock()
 }
 
 // TestLessorRevoke ensures Lessor can revoke a lease.
@@ -47,16 +63,21 @@ func TestLessorGrant(t *testing.T) {
 // the DeleteableKV.
 // The revoked lease cannot be got from Lessor again.
 func TestLessorRevoke(t *testing.T) {
+	dir, be := NewTestBackend(t)
+	defer os.RemoveAll(dir)
+	defer be.Close()
+
 	fd := &fakeDeleteable{}
-	le := NewLessor(1, fd)
+
+	le := NewLessor(1, be, fd)
 
 	// grant a lease with long term (100 seconds) to
 	// avoid early termination during the test.
-	l := le.Grant(time.Now().Add(100 * time.Second))
+	l := le.Grant(100)
 
 	items := []leaseItem{
-		{"foo", ""},
-		{"bar", "zar"},
+		{"foo"},
+		{"bar"},
 	}
 
 	err := le.Attach(l.id, items)
@@ -73,22 +94,36 @@ func TestLessorRevoke(t *testing.T) {
 		t.Errorf("got revoked lease %x", l.id)
 	}
 
-	wdeleted := []string{"foo_", "bar_zar"}
+	wdeleted := []string{"foo_", "bar_"}
 	if !reflect.DeepEqual(fd.deleted, wdeleted) {
 		t.Errorf("deleted= %v, want %v", fd.deleted, wdeleted)
 	}
+
+	be.BatchTx().Lock()
+	_, vs := be.BatchTx().UnsafeRange(leaseBucketName, int64ToBytes(l.id), nil, 0)
+	if len(vs) != 0 {
+		t.Errorf("len(vs) = %d, want 0", len(vs))
+	}
+	be.BatchTx().Unlock()
 }
 
 // TestLessorRenew ensures Lessor can renew an existing lease.
 func TestLessorRenew(t *testing.T) {
-	le := NewLessor(1, &fakeDeleteable{})
-	l := le.Grant(time.Now().Add(5 * time.Second))
+	dir, be := NewTestBackend(t)
+	defer be.Close()
+	defer os.RemoveAll(dir)
 
-	le.Renew(l.id, time.Now().Add(100*time.Second))
+	le := NewLessor(1, be, &fakeDeleteable{})
+	l := le.Grant(5)
+
+	// manually change the ttl field
+	l.ttl = 10
+
+	le.Renew(l.id)
 	l = le.get(l.id)
 
-	if l.expiry.Sub(time.Now()) < 95*time.Second {
-		t.Errorf("failed to renew the lease for 100 seconds")
+	if l.expiry.Sub(time.Now()) < 9*time.Second {
+		t.Errorf("failed to renew the lease")
 	}
 }
 
@@ -100,3 +135,12 @@ func (fd *fakeDeleteable) DeleteRange(key, end []byte) (int64, int64) {
 	fd.deleted = append(fd.deleted, string(key)+"_"+string(end))
 	return 0, 0
 }
+
+func NewTestBackend(t *testing.T) (string, backend.Backend) {
+	tmpPath, err := ioutil.TempDir("", "lease")
+	if err != nil {
+		t.Fatalf("failed to create tmpdir (%v)", err)
+	}
+
+	return tmpPath, backend.New(path.Join(tmpPath, "be"), time.Second, 10000)
+}

scripts/genproto.sh

@@ -20,7 +20,7 @@ PREFIX="github.com/coreos/etcd/Godeps/_workspace/src"
 ESCAPED_PREFIX=$(echo $PREFIX | sed -e 's/[\/&]/\\&/g')
 
 # directories containing protos to be built
-DIRS="./wal/walpb ./etcdserver/etcdserverpb ./snap/snappb ./raft/raftpb ./storage/storagepb"
+DIRS="./wal/walpb ./etcdserver/etcdserverpb ./snap/snappb ./raft/raftpb ./storage/storagepb ./lease/leasepb"
 
 # exact version of protoc-gen-gogo to build
 SHA="932b70afa8b0bf4a8e167fdf0c3367cebba45903"