grpc lock service

clientv3/client.go

@@ -77,6 +77,14 @@ func New(cfg Config) (*Client, error) {
 	return newClient(&cfg)
 }
 
+// NewCtxClient creates a client with a context but no underlying grpc
+// connection. This is useful for embedded cases that override the
+// service interface implementations and do not need connection management.
+func NewCtxClient(ctx context.Context) *Client {
+	cctx, cancel := context.WithCancel(ctx)
+	return &Client{ctx: cctx, cancel: cancel}
+}
+
 // NewFromURL creates a new etcdv3 client from a URL.
 func NewFromURL(url string) (*Client, error) {
 	return New(Config{Endpoints: []string{url}})
@@ -87,7 +95,10 @@ func (c *Client) Close() error {
 	c.cancel()
 	c.Watcher.Close()
 	c.Lease.Close()
-	return toErr(c.ctx, c.conn.Close())
+	if c.conn != nil {
+		return toErr(c.ctx, c.conn.Close())
+	}
+	return c.ctx.Err()
 }
 
 // Ctx is a context for "out of band" messages (e.g., for sending

clientv3/concurrency/election.go

@@ -69,7 +69,7 @@ func (e *Election) Campaign(ctx context.Context, val string) error {
 		}
 	}
 
-	err = waitDeletes(ctx, client, e.keyPrefix, e.leaderRev-1)
+	_, err = waitDeletes(ctx, client, e.keyPrefix, e.leaderRev-1)
 	if err != nil {
 		// clean up in case of context cancel
 		select {

clientv3/concurrency/key.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 
 	v3 "github.com/coreos/etcd/clientv3"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 	"github.com/coreos/etcd/mvcc/mvccpb"
 	"golang.org/x/net/context"
 )
@@ -46,19 +47,19 @@ func waitDelete(ctx context.Context, client *v3.Client, key string, rev int64) e
 
 // waitDeletes efficiently waits until all keys matching the prefix and no greater
 // than the create revision.
-func waitDeletes(ctx context.Context, client *v3.Client, pfx string, maxCreateRev int64) error {
+func waitDeletes(ctx context.Context, client *v3.Client, pfx string, maxCreateRev int64) (*pb.ResponseHeader, error) {
 	getOpts := append(v3.WithLastCreate(), v3.WithMaxCreateRev(maxCreateRev))
 	for {
 		resp, err := client.Get(ctx, pfx, getOpts...)
 		if err != nil {
-			return err
+			return nil, err
 		}
 		if len(resp.Kvs) == 0 {
-			return nil
+			return resp.Header, nil
 		}
 		lastKey := string(resp.Kvs[0].Key)
 		if err = waitDelete(ctx, client, lastKey, resp.Header.Revision); err != nil {
-			return err
+			return nil, err
 		}
 	}
 }

clientv3/concurrency/mutex.go

@@ -19,6 +19,7 @@ import (
 	"sync"
 
 	v3 "github.com/coreos/etcd/clientv3"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 	"golang.org/x/net/context"
 )
 
@@ -29,13 +30,14 @@ type Mutex struct {
 	pfx   string
 	myKey string
 	myRev int64
+	hdr   *pb.ResponseHeader
 }
 
 func NewMutex(s *Session, pfx string) *Mutex {
-	return &Mutex{s, pfx + "/", "", -1}
+	return &Mutex{s, pfx + "/", "", -1, nil}
 }
 
-// Lock locks the mutex with a cancellable context. If the context is cancelled
+// Lock locks the mutex with a cancelable context. If the context is canceled
 // while trying to acquire the lock, the mutex tries to clean its stale lock entry.
 func (m *Mutex) Lock(ctx context.Context) error {
 	s := m.s
@@ -57,14 +59,15 @@ func (m *Mutex) Lock(ctx context.Context) error {
 	}
 
 	// wait for deletion revisions prior to myKey
-	err = waitDeletes(ctx, client, m.pfx, m.myRev-1)
+	hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
 	// release lock key if cancelled
 	select {
 	case <-ctx.Done():
 		m.Unlock(client.Ctx())
 	default:
+		m.hdr = hdr
 	}
-	return err
+	return werr
 }
 
 func (m *Mutex) Unlock(ctx context.Context) error {
@@ -83,6 +86,9 @@ func (m *Mutex) IsOwner() v3.Cmp {
 
 func (m *Mutex) Key() string { return m.myKey }
 
+// Header is the response header received from etcd on acquiring the lock.
+func (m *Mutex) Header() *pb.ResponseHeader { return m.hdr }
+
 type lockerMutex struct{ *Mutex }
 
 func (lm *lockerMutex) Lock() {

embed/serve.go

@@ -25,6 +25,9 @@ import (
 	"time"
 
 	"github.com/coreos/etcd/etcdserver"
+	"github.com/coreos/etcd/etcdserver/api/v3client"
+	"github.com/coreos/etcd/etcdserver/api/v3lock"
+	"github.com/coreos/etcd/etcdserver/api/v3lock/v3lockpb"
 	"github.com/coreos/etcd/etcdserver/api/v3rpc"
 	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 	"github.com/coreos/etcd/pkg/transport"
@@ -68,6 +71,7 @@ func (sctx *serveCtx) serve(s *etcdserver.EtcdServer, tlscfg *tls.Config, handle
 
 	if sctx.insecure {
 		gs := v3rpc.Server(s, nil)
+		v3lockpb.RegisterLockServer(gs, v3lock.NewLockServer(v3client.New(s)))
 		if sctx.serviceRegister != nil {
 			sctx.serviceRegister(gs)
 		}
@@ -95,6 +99,7 @@ func (sctx *serveCtx) serve(s *etcdserver.EtcdServer, tlscfg *tls.Config, handle
 
 	if sctx.secure {
 		gs := v3rpc.Server(s, tlscfg)
+		v3lockpb.RegisterLockServer(gs, v3lock.NewLockServer(v3client.New(s)))
 		if sctx.serviceRegister != nil {
 			sctx.serviceRegister(gs)
 		}

etcdserver/api/v3client/doc.go

@@ -0,0 +1,16 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3client provides clientv3 interfaces from an etcdserver.
+package v3client

etcdserver/api/v3client/v3client.go

@@ -0,0 +1,40 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3client
+
+import (
+	"context"
+	"time"
+
+	"github.com/coreos/etcd/clientv3"
+	"github.com/coreos/etcd/etcdserver"
+	"github.com/coreos/etcd/etcdserver/api/v3rpc"
+	"github.com/coreos/etcd/proxy/grpcproxy/adapter"
+)
+
+func New(s *etcdserver.EtcdServer) *clientv3.Client {
+	c := clientv3.NewCtxClient(context.Background())
+
+	kvc := adapter.KvServerToKvClient(v3rpc.NewQuotaKVServer(s))
+	c.KV = clientv3.NewKVFromKVClient(kvc)
+
+	lc := adapter.LeaseServerToLeaseClient(v3rpc.NewQuotaLeaseServer(s))
+	c.Lease = clientv3.NewLeaseFromLeaseClient(lc, time.Second)
+
+	wc := adapter.WatchServerToWatchClient(v3rpc.NewWatchServer(s))
+	c.Watcher = clientv3.NewWatchFromWatchClient(wc)
+
+	return c
+}

etcdserver/api/v3lock/doc.go

@@ -0,0 +1,16 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3lock provides a v3 locking service from an etcdserver.
+package v3lock

etcdserver/api/v3lock/lock.go

@@ -0,0 +1,56 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3lock
+
+import (
+	"golang.org/x/net/context"
+
+	"github.com/coreos/etcd/clientv3"
+	"github.com/coreos/etcd/clientv3/concurrency"
+	"github.com/coreos/etcd/etcdserver/api/v3lock/v3lockpb"
+)
+
+type lockServer struct {
+	c *clientv3.Client
+}
+
+func NewLockServer(c *clientv3.Client) v3lockpb.LockServer {
+	return &lockServer{c}
+}
+
+func (ls *lockServer) Lock(ctx context.Context, req *v3lockpb.LockRequest) (*v3lockpb.LockResponse, error) {
+	s, err := concurrency.NewSession(
+		ls.c,
+		concurrency.WithLease(clientv3.LeaseID(req.Lease)),
+		concurrency.WithContext(ctx),
+	)
+	if err != nil {
+		return nil, err
+	}
+	s.Orphan()
+	m := concurrency.NewMutex(s, string(req.Name))
+	if err = m.Lock(ctx); err != nil {
+		return nil, err
+	}
+	return &v3lockpb.LockResponse{Header: m.Header(), Key: []byte(m.Key())}, nil
+}
+
+func (ls *lockServer) Unlock(ctx context.Context, req *v3lockpb.UnlockRequest) (*v3lockpb.UnlockResponse, error) {
+	resp, err := ls.c.Delete(ctx, string(req.Key))
+	if err != nil {
+		return nil, err
+	}
+	return &v3lockpb.UnlockResponse{Header: resp.Header}, nil
+}