forked from weaveworks/mesh
/
etcd_store.go
813 lines (720 loc) · 22.1 KB
/
etcd_store.go
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package metcd
import (
"bytes"
"errors"
"fmt"
"io/ioutil"
"os"
"sort"
"github.com/coreos/etcd/etcdserver/etcdserverpb"
"github.com/coreos/etcd/lease"
"github.com/coreos/etcd/mvcc"
"github.com/coreos/etcd/mvcc/backend"
"github.com/coreos/etcd/mvcc/mvccpb"
"github.com/coreos/etcd/raft/raftpb"
"github.com/gogo/protobuf/proto"
"github.com/weaveworks/mesh"
"golang.org/x/net/context"
)
// Transport-agnostic reimplementation of coreos/etcd/etcdserver. The original
// is unsuitable because it is tightly coupled to persistent storage, an HTTP
// transport, etc. Implements selected etcd V3 API (gRPC) methods.
type etcdStore struct {
proposalc chan<- []byte
snapshotc <-chan raftpb.Snapshot
entryc <-chan raftpb.Entry
confentryc chan<- raftpb.Entry
actionc chan func()
quitc chan struct{}
terminatedc chan struct{}
logger mesh.Logger
dbPath string // please os.RemoveAll on exit
kv mvcc.KV
lessor lease.Lessor
index *consistentIndex // see comment on type
idgen <-chan uint64
pending map[uint64]responseChans
}
var _ Server = &etcdStore{}
func newEtcdStore(
proposalc chan<- []byte,
snapshotc <-chan raftpb.Snapshot,
entryc <-chan raftpb.Entry,
confentryc chan<- raftpb.Entry,
logger mesh.Logger,
) *etcdStore {
// It would be much better if we could have a proper in-memory backend. Alas:
// backend.Backend is tightly coupled to bolt.DB, and both are tightly coupled
// to os.Open &c. So we'd need to fork both Bolt and backend. A task for
// another day.
f, err := ioutil.TempFile(os.TempDir(), "mesh_etcd_backend_")
if err != nil {
panic(err)
}
dbPath := f.Name()
f.Close()
logger.Printf("etcd store: using %s", dbPath)
b := backend.NewDefaultBackend(dbPath)
lessor := lease.NewLessor(b)
index := &consistentIndex{0}
kv := mvcc.New(b, lessor, index)
s := &etcdStore{
proposalc: proposalc,
snapshotc: snapshotc,
entryc: entryc,
confentryc: confentryc,
actionc: make(chan func()),
quitc: make(chan struct{}),
terminatedc: make(chan struct{}),
logger: logger,
dbPath: dbPath,
kv: kv,
lessor: lessor,
index: index,
idgen: makeIDGen(),
pending: map[uint64]responseChans{},
}
go s.loop()
return s
}
// Range implements gRPC KVServer.
// Range gets the keys in the range from the store.
func (s *etcdStore) Range(ctx context.Context, req *etcdserverpb.RangeRequest) (*etcdserverpb.RangeResponse, error) {
ireq := etcdserverpb.InternalRaftRequest{ID: <-s.idgen, Range: req}
msgc, errc, err := s.proposeInternalRaftRequest(ireq)
if err != nil {
return nil, err
}
select {
case <-ctx.Done():
s.cancelInternalRaftRequest(ireq)
return nil, ctx.Err()
case msg := <-msgc:
return msg.(*etcdserverpb.RangeResponse), nil
case err := <-errc:
return nil, err
case <-s.quitc:
return nil, errStopped
}
}
// Put implements gRPC KVServer.
// Put puts the given key into the store.
// A put request increases the revision of the store,
// and generates one event in the event history.
func (s *etcdStore) Put(ctx context.Context, req *etcdserverpb.PutRequest) (*etcdserverpb.PutResponse, error) {
ireq := etcdserverpb.InternalRaftRequest{ID: <-s.idgen, Put: req}
msgc, errc, err := s.proposeInternalRaftRequest(ireq)
if err != nil {
return nil, err
}
select {
case <-ctx.Done():
s.cancelInternalRaftRequest(ireq)
return nil, ctx.Err()
case msg := <-msgc:
return msg.(*etcdserverpb.PutResponse), nil
case err := <-errc:
return nil, err
case <-s.quitc:
return nil, errStopped
}
}
// Delete implements gRPC KVServer.
// Delete deletes the given range from the store.
// A delete request increase the revision of the store,
// and generates one event in the event history.
func (s *etcdStore) DeleteRange(ctx context.Context, req *etcdserverpb.DeleteRangeRequest) (*etcdserverpb.DeleteRangeResponse, error) {
ireq := etcdserverpb.InternalRaftRequest{ID: <-s.idgen, DeleteRange: req}
msgc, errc, err := s.proposeInternalRaftRequest(ireq)
if err != nil {
return nil, err
}
select {
case <-ctx.Done():
s.cancelInternalRaftRequest(ireq)
return nil, ctx.Err()
case msg := <-msgc:
return msg.(*etcdserverpb.DeleteRangeResponse), nil
case err := <-errc:
return nil, err
case <-s.quitc:
return nil, errStopped
}
}
// Txn implements gRPC KVServer.
// Txn processes all the requests in one transaction.
// A txn request increases the revision of the store,
// and generates events with the same revision in the event history.
// It is not allowed to modify the same key several times within one txn.
func (s *etcdStore) Txn(ctx context.Context, req *etcdserverpb.TxnRequest) (*etcdserverpb.TxnResponse, error) {
ireq := etcdserverpb.InternalRaftRequest{ID: <-s.idgen, Txn: req}
msgc, errc, err := s.proposeInternalRaftRequest(ireq)
if err != nil {
return nil, err
}
select {
case <-ctx.Done():
s.cancelInternalRaftRequest(ireq)
return nil, ctx.Err()
case msg := <-msgc:
return msg.(*etcdserverpb.TxnResponse), nil
case err := <-errc:
return nil, err
case <-s.quitc:
return nil, errStopped
}
}
// Compact implements gRPC KVServer.
// Compact compacts the event history in s. User should compact the
// event history periodically, or it will grow infinitely.
func (s *etcdStore) Compact(ctx context.Context, req *etcdserverpb.CompactionRequest) (*etcdserverpb.CompactionResponse, error) {
// We don't have snapshotting yet, so compact just puts us in a bad state.
// TODO(pb): fix this when we implement snapshotting.
return nil, errors.New("not implemented")
}
// The "consistent index" is the index number of the most recent committed
// entry. This logical value is duplicated and tracked in multiple places
// throughout the etcd server and storage code.
//
// For our part, we are expected to store one instance of this number, setting
// it whenever we receive a committed entry via entryc, and making it available
// for queries.
//
// The etcd storage backend is given a reference to this instance in the form of
// a ConsistentIndexGetter interface. In addition, it tracks its own view of the
// consistent index in a special bucket+key. See package etcd/mvcc, type
// consistentWatchableStore, method consistentIndex.
//
// Whenever a user makes an e.g. Put request, these values are compared. If
// there is some inconsistency, the transaction is marked as "skip" and becomes
// a no-op. This happens transparently to the user. See package etcd/mvcc,
// type consistentWatchableStore, method TxnBegin.
//
// tl;dr: (ಠ_ಠ)
type consistentIndex struct{ i uint64 }
func (i *consistentIndex) ConsistentIndex() uint64 { return i.i }
func (i *consistentIndex) set(index uint64) { i.i = index }
func makeIDGen() <-chan uint64 {
c := make(chan uint64)
go func() {
var i uint64 = 1
for {
c <- i
i++
}
}()
return c
}
const (
maxRequestBytes = 8192
)
var (
errStopped = errors.New("etcd store was stopped")
errTooBig = errors.New("request too large to send")
errCanceled = errors.New("request canceled")
)
type responseChans struct {
msgc chan<- proto.Message
errc chan<- error
}
func (s *etcdStore) loop() {
defer close(s.terminatedc)
defer s.removeDB()
for {
select {
case snapshot := <-s.snapshotc:
if err := s.applySnapshot(snapshot); err != nil {
s.logger.Printf("etcd store: apply snapshot: %v", err)
}
case entry := <-s.entryc:
if err := s.applyCommittedEntry(entry); err != nil {
s.logger.Printf("etcd store: apply committed entry: %v", err)
}
case f := <-s.actionc:
f()
case <-s.quitc:
return
}
}
}
func (s *etcdStore) stop() {
close(s.quitc)
<-s.terminatedc
}
func (s *etcdStore) applySnapshot(snapshot raftpb.Snapshot) error {
if len(snapshot.Data) == 0 {
//s.logger.Printf("etcd store: apply snapshot with empty snapshot; skipping")
return nil
}
s.logger.Printf("etcd store: applying snapshot: size %d", len(snapshot.Data))
s.logger.Printf("etcd store: applying snapshot: metadata %s", snapshot.Metadata.String())
s.logger.Printf("etcd store: applying snapshot: TODO") // TODO(pb)
return nil
}
func (s *etcdStore) applyCommittedEntry(entry raftpb.Entry) error {
// Set the consistent index regardless of the outcome. Because we need to do
// this for all committed entries, we need to receive all committed entries,
// and must therefore take responsibility to demux the conf changes to the
// configurator via confentryc.
//
// This requirement is unique to the etcd store. But for symmetry, we assign
// the same responsibility to the simple store.
s.index.set(entry.Index)
switch entry.Type {
case raftpb.EntryNormal:
break
case raftpb.EntryConfChange:
s.logger.Printf("etcd store: forwarding ConfChange entry")
s.confentryc <- entry
return nil
default:
s.logger.Printf("etcd store: got unknown entry type %s", entry.Type)
return fmt.Errorf("unknown entry type %d", entry.Type)
}
// entry.Size can be nonzero when len(entry.Data) == 0
if len(entry.Data) <= 0 {
s.logger.Printf("etcd store: got empty committed entry (term %d, index %d, type %s); skipping", entry.Term, entry.Index, entry.Type)
return nil
}
var req etcdserverpb.InternalRaftRequest
if err := req.Unmarshal(entry.Data); err != nil {
s.logger.Printf("etcd store: unmarshaling entry data: %v", err)
return err
}
msg, err := s.applyInternalRaftRequest(req)
if err != nil {
s.logger.Printf("etcd store: applying internal Raft request %d: %v", req.ID, err)
s.cancelPending(req.ID, err)
return err
}
s.signalPending(req.ID, msg)
return nil
}
// From public API method to proposalc.
func (s *etcdStore) proposeInternalRaftRequest(req etcdserverpb.InternalRaftRequest) (<-chan proto.Message, <-chan error, error) {
data, err := req.Marshal()
if err != nil {
return nil, nil, err
}
if len(data) > maxRequestBytes {
return nil, nil, errTooBig
}
msgc, errc, err := s.registerPending(req.ID)
if err != nil {
return nil, nil, err
}
s.proposalc <- data
return msgc, errc, nil
}
func (s *etcdStore) cancelInternalRaftRequest(req etcdserverpb.InternalRaftRequest) {
s.cancelPending(req.ID, errCanceled)
}
// From committed entryc, back to public API method.
// etcdserver/v3demo_server.go applyV3Result
func (s *etcdStore) applyInternalRaftRequest(req etcdserverpb.InternalRaftRequest) (proto.Message, error) {
switch {
case req.Range != nil:
return applyRange(noTxn, s.kv, req.Range)
case req.Put != nil:
return applyPut(noTxn, s.kv, s.lessor, req.Put)
case req.DeleteRange != nil:
return applyDeleteRange(noTxn, s.kv, req.DeleteRange)
case req.Txn != nil:
return applyTransaction(s.kv, s.lessor, req.Txn)
case req.Compaction != nil:
return applyCompaction(s.kv, req.Compaction)
case req.LeaseGrant != nil:
return applyLeaseGrant(s.lessor, req.LeaseGrant)
case req.LeaseRevoke != nil:
return applyLeaseRevoke(s.lessor, req.LeaseRevoke)
default:
return nil, fmt.Errorf("internal Raft request type not implemented")
}
}
func (s *etcdStore) registerPending(id uint64) (<-chan proto.Message, <-chan error, error) {
if _, ok := s.pending[id]; ok {
return nil, nil, fmt.Errorf("pending ID %d already registered", id)
}
msgc := make(chan proto.Message)
errc := make(chan error)
s.pending[id] = responseChans{msgc, errc}
return msgc, errc, nil
}
func (s *etcdStore) signalPending(id uint64, msg proto.Message) {
rc, ok := s.pending[id]
if !ok {
// InternalRaftRequests are replicated via Raft. So all peers will
// invoke this method for all messages on commit. But only the peer that
// serviced the API request will have an operating pending. So, this is
// a normal "failure" mode.
return
}
rc.msgc <- msg
delete(s.pending, id)
}
func (s *etcdStore) cancelPending(id uint64, err error) {
rc, ok := s.pending[id]
if !ok {
s.logger.Printf("etcd store: cancel pending ID %d, but nothing was pending; strange", id)
return
}
rc.errc <- err
delete(s.pending, id)
}
func (s *etcdStore) removeDB() {
s.logger.Printf("etcd store: removing tmp DB %s", s.dbPath)
if err := os.RemoveAll(s.dbPath); err != nil {
s.logger.Printf("etcd store: removing tmp DB %s: %v", s.dbPath, err)
}
}
// Sentinel value to indicate the operation is not part of a transaction.
const noTxn = -1
// isGteRange determines if the range end is a >= range. This works around grpc
// sending empty byte strings as nil; >= is encoded in the range end as '\0'.
func isGteRange(rangeEnd []byte) bool {
return len(rangeEnd) == 1 && rangeEnd[0] == 0
}
func applyRange(txnID int64, kv mvcc.KV, r *etcdserverpb.RangeRequest) (*etcdserverpb.RangeResponse, error) {
resp := &etcdserverpb.RangeResponse{}
resp.Header = &etcdserverpb.ResponseHeader{}
var (
kvs []mvccpb.KeyValue
rev int64
err error
)
if isGteRange(r.RangeEnd) {
r.RangeEnd = []byte{}
}
limit := r.Limit
if r.SortOrder != etcdserverpb.RangeRequest_NONE {
// fetch everything; sort and truncate afterwards
limit = 0
}
if limit > 0 {
// fetch one extra for 'more' flag
limit = limit + 1
}
if txnID != noTxn {
kvs, rev, err = kv.TxnRange(txnID, r.Key, r.RangeEnd, limit, r.Revision)
if err != nil {
return nil, err
}
} else {
kvs, rev, err = kv.Range(r.Key, r.RangeEnd, limit, r.Revision)
if err != nil {
return nil, err
}
}
if r.SortOrder != etcdserverpb.RangeRequest_NONE {
var sorter sort.Interface
switch {
case r.SortTarget == etcdserverpb.RangeRequest_KEY:
sorter = &kvSortByKey{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_VERSION:
sorter = &kvSortByVersion{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_CREATE:
sorter = &kvSortByCreate{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_MOD:
sorter = &kvSortByMod{&kvSort{kvs}}
case r.SortTarget == etcdserverpb.RangeRequest_VALUE:
sorter = &kvSortByValue{&kvSort{kvs}}
}
switch {
case r.SortOrder == etcdserverpb.RangeRequest_ASCEND:
sort.Sort(sorter)
case r.SortOrder == etcdserverpb.RangeRequest_DESCEND:
sort.Sort(sort.Reverse(sorter))
}
}
if r.Limit > 0 && len(kvs) > int(r.Limit) {
kvs = kvs[:r.Limit]
resp.More = true
}
resp.Header.Revision = rev
for i := range kvs {
resp.Kvs = append(resp.Kvs, &kvs[i])
}
return resp, nil
}
type kvSort struct{ kvs []mvccpb.KeyValue }
func (s *kvSort) Swap(i, j int) {
t := s.kvs[i]
s.kvs[i] = s.kvs[j]
s.kvs[j] = t
}
func (s *kvSort) Len() int { return len(s.kvs) }
type kvSortByKey struct{ *kvSort }
func (s *kvSortByKey) Less(i, j int) bool {
return bytes.Compare(s.kvs[i].Key, s.kvs[j].Key) < 0
}
type kvSortByVersion struct{ *kvSort }
func (s *kvSortByVersion) Less(i, j int) bool {
return (s.kvs[i].Version - s.kvs[j].Version) < 0
}
type kvSortByCreate struct{ *kvSort }
func (s *kvSortByCreate) Less(i, j int) bool {
return (s.kvs[i].CreateRevision - s.kvs[j].CreateRevision) < 0
}
type kvSortByMod struct{ *kvSort }
func (s *kvSortByMod) Less(i, j int) bool {
return (s.kvs[i].ModRevision - s.kvs[j].ModRevision) < 0
}
type kvSortByValue struct{ *kvSort }
func (s *kvSortByValue) Less(i, j int) bool {
return bytes.Compare(s.kvs[i].Value, s.kvs[j].Value) < 0
}
func applyPut(txnID int64, kv mvcc.KV, lessor lease.Lessor, req *etcdserverpb.PutRequest) (*etcdserverpb.PutResponse, error) {
resp := &etcdserverpb.PutResponse{}
resp.Header = &etcdserverpb.ResponseHeader{}
var (
rev int64
err error
)
if txnID != noTxn {
rev, err = kv.TxnPut(txnID, req.Key, req.Value, lease.LeaseID(req.Lease))
if err != nil {
return nil, err
}
} else {
leaseID := lease.LeaseID(req.Lease)
if leaseID != lease.NoLease {
if l := lessor.Lookup(leaseID); l == nil {
return nil, lease.ErrLeaseNotFound
}
}
rev = kv.Put(req.Key, req.Value, leaseID)
}
resp.Header.Revision = rev
return resp, nil
}
func applyDeleteRange(txnID int64, kv mvcc.KV, req *etcdserverpb.DeleteRangeRequest) (*etcdserverpb.DeleteRangeResponse, error) {
resp := &etcdserverpb.DeleteRangeResponse{}
resp.Header = &etcdserverpb.ResponseHeader{}
var (
n int64
rev int64
err error
)
if isGteRange(req.RangeEnd) {
req.RangeEnd = []byte{}
}
if txnID != noTxn {
n, rev, err = kv.TxnDeleteRange(txnID, req.Key, req.RangeEnd)
if err != nil {
return nil, err
}
} else {
n, rev = kv.DeleteRange(req.Key, req.RangeEnd)
}
resp.Deleted = n
resp.Header.Revision = rev
return resp, nil
}
func applyTransaction(kv mvcc.KV, lessor lease.Lessor, req *etcdserverpb.TxnRequest) (*etcdserverpb.TxnResponse, error) {
var revision int64
ok := true
for _, c := range req.Compare {
if revision, ok = applyCompare(kv, c); !ok {
break
}
}
var reqs []*etcdserverpb.RequestUnion
if ok {
reqs = req.Success
} else {
reqs = req.Failure
}
if err := checkRequestLeases(lessor, reqs); err != nil {
return nil, err
}
if err := checkRequestRange(kv, reqs); err != nil {
return nil, err
}
// When executing the operations of txn, we need to hold the txn lock.
// So the reader will not see any intermediate results.
txnID := kv.TxnBegin()
defer func() {
err := kv.TxnEnd(txnID)
if err != nil {
panic(fmt.Sprint("unexpected error when closing txn", txnID))
}
}()
resps := make([]*etcdserverpb.ResponseUnion, len(reqs))
for i := range reqs {
resps[i] = applyUnion(txnID, kv, reqs[i])
}
if len(resps) != 0 {
revision++
}
txnResp := &etcdserverpb.TxnResponse{}
txnResp.Header = &etcdserverpb.ResponseHeader{}
txnResp.Header.Revision = revision
txnResp.Responses = resps
txnResp.Succeeded = ok
return txnResp, nil
}
func checkRequestLeases(le lease.Lessor, reqs []*etcdserverpb.RequestUnion) error {
for _, requ := range reqs {
tv, ok := requ.Request.(*etcdserverpb.RequestUnion_RequestPut)
if !ok {
continue
}
preq := tv.RequestPut
if preq == nil || lease.LeaseID(preq.Lease) == lease.NoLease {
continue
}
if l := le.Lookup(lease.LeaseID(preq.Lease)); l == nil {
return lease.ErrLeaseNotFound
}
}
return nil
}
func checkRequestRange(kv mvcc.KV, reqs []*etcdserverpb.RequestUnion) error {
for _, requ := range reqs {
tv, ok := requ.Request.(*etcdserverpb.RequestUnion_RequestRange)
if !ok {
continue
}
greq := tv.RequestRange
if greq == nil || greq.Revision == 0 {
continue
}
if greq.Revision > kv.Rev() {
return mvcc.ErrFutureRev
}
if greq.Revision < kv.FirstRev() {
return mvcc.ErrCompacted
}
}
return nil
}
func applyUnion(txnID int64, kv mvcc.KV, union *etcdserverpb.RequestUnion) *etcdserverpb.ResponseUnion {
switch tv := union.Request.(type) {
case *etcdserverpb.RequestUnion_RequestRange:
if tv.RequestRange != nil {
resp, err := applyRange(txnID, kv, tv.RequestRange)
if err != nil {
panic("unexpected error during txn")
}
return &etcdserverpb.ResponseUnion{Response: &etcdserverpb.ResponseUnion_ResponseRange{ResponseRange: resp}}
}
case *etcdserverpb.RequestUnion_RequestPut:
if tv.RequestPut != nil {
resp, err := applyPut(txnID, kv, nil, tv.RequestPut)
if err != nil {
panic("unexpected error during txn")
}
return &etcdserverpb.ResponseUnion{Response: &etcdserverpb.ResponseUnion_ResponsePut{ResponsePut: resp}}
}
case *etcdserverpb.RequestUnion_RequestDeleteRange:
if tv.RequestDeleteRange != nil {
resp, err := applyDeleteRange(txnID, kv, tv.RequestDeleteRange)
if err != nil {
panic("unexpected error during txn")
}
return &etcdserverpb.ResponseUnion{Response: &etcdserverpb.ResponseUnion_ResponseDeleteRange{ResponseDeleteRange: resp}}
}
default:
// empty union
return nil
}
return nil
}
// applyCompare applies the compare request.
// It returns the revision at which the comparison happens. If the comparison
// succeeds, the it returns true. Otherwise it returns false.
func applyCompare(kv mvcc.KV, c *etcdserverpb.Compare) (int64, bool) {
ckvs, rev, err := kv.Range(c.Key, nil, 1, 0)
if err != nil {
if err == mvcc.ErrTxnIDMismatch {
panic("unexpected txn ID mismatch error")
}
return rev, false
}
var ckv mvccpb.KeyValue
if len(ckvs) != 0 {
ckv = ckvs[0]
} else {
// Use the zero value of ckv normally. However...
if c.Target == etcdserverpb.Compare_VALUE {
// Always fail if we're comparing a value on a key that doesn't exist.
// We can treat non-existence as the empty set explicitly, such that
// even a key with a value of length 0 bytes is still a real key
// that was written that way
return rev, false
}
}
// -1 is less, 0 is equal, 1 is greater
var result int
switch c.Target {
case etcdserverpb.Compare_VALUE:
tv, _ := c.TargetUnion.(*etcdserverpb.Compare_Value)
if tv != nil {
result = bytes.Compare(ckv.Value, tv.Value)
}
case etcdserverpb.Compare_CREATE:
tv, _ := c.TargetUnion.(*etcdserverpb.Compare_CreateRevision)
if tv != nil {
result = compareInt64(ckv.CreateRevision, tv.CreateRevision)
}
case etcdserverpb.Compare_MOD:
tv, _ := c.TargetUnion.(*etcdserverpb.Compare_ModRevision)
if tv != nil {
result = compareInt64(ckv.ModRevision, tv.ModRevision)
}
case etcdserverpb.Compare_VERSION:
tv, _ := c.TargetUnion.(*etcdserverpb.Compare_Version)
if tv != nil {
result = compareInt64(ckv.Version, tv.Version)
}
}
switch c.Result {
case etcdserverpb.Compare_EQUAL:
if result != 0 {
return rev, false
}
case etcdserverpb.Compare_GREATER:
if result != 1 {
return rev, false
}
case etcdserverpb.Compare_LESS:
if result != -1 {
return rev, false
}
}
return rev, true
}
func compareInt64(a, b int64) int {
switch {
case a < b:
return -1
case a > b:
return 1
default:
return 0
}
}
func applyCompaction(kv mvcc.KV, req *etcdserverpb.CompactionRequest) (*etcdserverpb.CompactionResponse, error) {
resp := &etcdserverpb.CompactionResponse{}
resp.Header = &etcdserverpb.ResponseHeader{}
_, err := kv.Compact(req.Revision)
if err != nil {
return nil, err
}
// get the current revision. which key to get is not important.
_, resp.Header.Revision, _ = kv.Range([]byte("compaction"), nil, 1, 0)
return resp, err
}
func applyLeaseGrant(lessor lease.Lessor, req *etcdserverpb.LeaseGrantRequest) (*etcdserverpb.LeaseGrantResponse, error) {
l, err := lessor.Grant(lease.LeaseID(req.ID), req.TTL)
resp := &etcdserverpb.LeaseGrantResponse{}
if err == nil {
resp.ID = int64(l.ID)
resp.TTL = l.TTL
}
return resp, err
}
func applyLeaseRevoke(lessor lease.Lessor, req *etcdserverpb.LeaseRevokeRequest) (*etcdserverpb.LeaseRevokeResponse, error) {
err := lessor.Revoke(lease.LeaseID(req.ID))
return &etcdserverpb.LeaseRevokeResponse{}, err
}