api: nested txns

Documentation/dev-guide/api_reference_v3.md

@@ -669,6 +669,7 @@ Empty field.
 | request_range |  | RangeRequest |
 | request_put |  | PutRequest |
 | request_delete_range |  | DeleteRangeRequest |
+| request_txn |  | TxnRequest |
 
 
 
@@ -691,6 +692,7 @@ Empty field.
 | response_range |  | RangeResponse |
 | response_put |  | PutResponse |
 | response_delete_range |  | DeleteRangeResponse |
+| response_txn |  | TxnResponse |
 
 
 

Documentation/dev-guide/apispec/swagger/rpc.swagger.json

@@ -1954,6 +1954,9 @@
         },
         "request_range": {
           "$ref": "#/definitions/etcdserverpbRangeRequest"
+        },
+        "request_txn": {
+          "$ref": "#/definitions/etcdserverpbTxnRequest"
         }
       }
     },
@@ -1993,6 +1996,9 @@
         },
         "response_range": {
           "$ref": "#/definitions/etcdserverpbRangeResponse"
+        },
+        "response_txn": {
+          "$ref": "#/definitions/etcdserverpbTxnResponse"
         }
       }
     },

clientv3/integration/txn_test.go

@@ -106,27 +106,35 @@ func TestTxnReadRetry(t *testing.T) {
 	defer clus.Terminate(t)
 
 	kv := clus.Client(0)
-	clus.Members[0].Stop(t)
-	<-clus.Members[0].StopNotify()
 
-	donec := make(chan struct{})
-	go func() {
-		ctx := context.TODO()
-		_, err := kv.Txn(ctx).Then(clientv3.OpGet("foo")).Commit()
-		if err != nil {
-			t.Fatalf("expected response, got error %v", err)
+	thenOps := [][]clientv3.Op{
+		{clientv3.OpGet("foo")},
+		{clientv3.OpTxn(nil, []clientv3.Op{clientv3.OpGet("foo")}, nil)},
+		{clientv3.OpTxn(nil, nil, nil)},
+		{},
+	}
+	for i := range thenOps {
+		clus.Members[0].Stop(t)
+		<-clus.Members[0].StopNotify()
+
+		donec := make(chan struct{})
+		go func() {
+			_, err := kv.Txn(context.TODO()).Then(thenOps[i]...).Commit()
+			if err != nil {
+				t.Fatalf("expected response, got error %v", err)
+			}
+			donec <- struct{}{}
+		}()
+		// wait for txn to fail on disconnect
+		time.Sleep(100 * time.Millisecond)
+
+		// restart node; client should resume
+		clus.Members[0].Restart(t)
+		select {
+		case <-donec:
+		case <-time.After(2 * clus.Members[1].ServerConfig.ReqTimeout()):
+			t.Fatalf("waited too long")
 		}
-		donec <- struct{}{}
-	}()
-	// wait for txn to fail on disconnect
-	time.Sleep(100 * time.Millisecond)
-
-	// restart node; client should resume
-	clus.Members[0].Restart(t)
-	select {
-	case <-donec:
-	case <-time.After(2 * clus.Members[1].ServerConfig.ReqTimeout()):
-		t.Fatalf("waited too long")
 	}
 }
 
@@ -179,3 +187,41 @@ func TestTxnCompareRange(t *testing.T) {
 		t.Fatal("expected prefix compare to false, got compares as true")
 	}
 }
+
+func TestTxnNested(t *testing.T) {
+	defer testutil.AfterTest(t)
+
+	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
+	defer clus.Terminate(t)
+
+	kv := clus.Client(0)
+
+	tresp, err := kv.Txn(context.TODO()).
+		If(clientv3.Compare(clientv3.Version("foo"), "=", 0)).
+		Then(
+			clientv3.OpPut("foo", "bar"),
+			clientv3.OpTxn(nil, []clientv3.Op{clientv3.OpPut("abc", "123")}, nil)).
+		Else(clientv3.OpPut("foo", "baz")).Commit()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(tresp.Responses) != 2 {
+		t.Errorf("expected 2 top-level txn responses, got %+v", tresp.Responses)
+	}
+
+	// check txn writes were applied
+	resp, err := kv.Get(context.TODO(), "foo")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(resp.Kvs) != 1 || string(resp.Kvs[0].Value) != "bar" {
+		t.Errorf("unexpected Get response %+v", resp)
+	}
+	resp, err = kv.Get(context.TODO(), "abc")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(resp.Kvs) != 1 || string(resp.Kvs[0].Value) != "123" {
+		t.Errorf("unexpected Get response %+v", resp)
+	}
+}

clientv3/kv.go

@@ -66,11 +66,13 @@ type OpResponse struct {
 	put *PutResponse
 	get *GetResponse
 	del *DeleteResponse
+	txn *TxnResponse
 }
 
 func (op OpResponse) Put() *PutResponse    { return op.put }
 func (op OpResponse) Get() *GetResponse    { return op.get }
 func (op OpResponse) Del() *DeleteResponse { return op.del }
+func (op OpResponse) Txn() *TxnResponse    { return op.txn }
 
 type kv struct {
 	remote pb.KVClient
@@ -134,7 +136,6 @@ func (kv *kv) Do(ctx context.Context, op Op) (OpResponse, error) {
 func (kv *kv) do(ctx context.Context, op Op) (OpResponse, error) {
 	var err error
 	switch op.t {
-	// TODO: handle other ops
 	case tRange:
 		var resp *pb.RangeResponse
 		resp, err = kv.remote.Range(ctx, op.toRangeRequest(), grpc.FailFast(false))
@@ -155,6 +156,12 @@ func (kv *kv) do(ctx context.Context, op Op) (OpResponse, error) {
 		if err == nil {
 			return OpResponse{del: (*DeleteResponse)(resp)}, nil
 		}
+	case tTxn:
+		var resp *pb.TxnResponse
+		resp, err = kv.remote.Txn(ctx, op.toTxnRequest())
+		if err == nil {
+			return OpResponse{txn: (*TxnResponse)(resp)}, nil
+		}
 	default:
 		panic("Unknown op")
 	}

clientv3/namespace/kv.go

@@ -74,7 +74,7 @@ func (kv *kvPrefix) Delete(ctx context.Context, key string, opts ...clientv3.OpO
 }
 
 func (kv *kvPrefix) Do(ctx context.Context, op clientv3.Op) (clientv3.OpResponse, error) {
-	if len(op.KeyBytes()) == 0 {
+	if len(op.KeyBytes()) == 0 && !op.IsTxn() {
 		return clientv3.OpResponse{}, rpctypes.ErrEmptyKey
 	}
 	r, err := kv.KV.Do(ctx, kv.prefixOp(op))
@@ -88,6 +88,8 @@ func (kv *kvPrefix) Do(ctx context.Context, op clientv3.Op) (clientv3.OpResponse
 		kv.unprefixPutResponse(r.Put())
 	case r.Del() != nil:
 		kv.unprefixDeleteResponse(r.Del())
+	case r.Txn() != nil:
+		kv.unprefixTxnResponse(r.Txn())
 	}
 	return r, nil
 }
@@ -102,34 +104,17 @@ func (kv *kvPrefix) Txn(ctx context.Context) clientv3.Txn {
 }
 
 func (txn *txnPrefix) If(cs ...clientv3.Cmp) clientv3.Txn {
-	newCmps := make([]clientv3.Cmp, len(cs))
-	for i := range cs {
-		newCmps[i] = cs[i]
-		pfxKey, endKey := txn.kv.prefixInterval(cs[i].KeyBytes(), cs[i].RangeEnd)
-		newCmps[i].WithKeyBytes(pfxKey)
-		if len(cs[i].RangeEnd) != 0 {
-			newCmps[i].RangeEnd = endKey
-		}
-	}
-	txn.Txn = txn.Txn.If(newCmps...)
+	txn.Txn = txn.Txn.If(txn.kv.prefixCmps(cs)...)
 	return txn
 }
 
 func (txn *txnPrefix) Then(ops ...clientv3.Op) clientv3.Txn {
-	newOps := make([]clientv3.Op, len(ops))
-	for i := range ops {
-		newOps[i] = txn.kv.prefixOp(ops[i])
-	}
-	txn.Txn = txn.Txn.Then(newOps...)
+	txn.Txn = txn.Txn.Then(txn.kv.prefixOps(ops)...)
 	return txn
 }
 
 func (txn *txnPrefix) Else(ops ...clientv3.Op) clientv3.Txn {
-	newOps := make([]clientv3.Op, len(ops))
-	for i := range ops {
-		newOps[i] = txn.kv.prefixOp(ops[i])
-	}
-	txn.Txn = txn.Txn.Else(newOps...)
+	txn.Txn = txn.Txn.Else(txn.kv.prefixOps(ops)...)
 	return txn
 }
 
@@ -143,10 +128,14 @@ func (txn *txnPrefix) Commit() (*clientv3.TxnResponse, error) {
 }
 
 func (kv *kvPrefix) prefixOp(op clientv3.Op) clientv3.Op {
-	begin, end := kv.prefixInterval(op.KeyBytes(), op.RangeBytes())
-	op.WithKeyBytes(begin)
-	op.WithRangeBytes(end)
-	return op
+	if !op.IsTxn() {
+		begin, end := kv.prefixInterval(op.KeyBytes(), op.RangeBytes())
+		op.WithKeyBytes(begin)
+		op.WithRangeBytes(end)
+		return op
+	}
+	cmps, thenOps, elseOps := op.Txn()
+	return clientv3.OpTxn(kv.prefixCmps(cmps), kv.prefixOps(thenOps), kv.prefixOps(elseOps))
 }
 
 func (kv *kvPrefix) unprefixGetResponse(resp *clientv3.GetResponse) {
@@ -182,6 +171,10 @@ func (kv *kvPrefix) unprefixTxnResponse(resp *clientv3.TxnResponse) {
 			if tv.ResponseDeleteRange != nil {
 				kv.unprefixDeleteResponse((*clientv3.DeleteResponse)(tv.ResponseDeleteRange))
 			}
+		case *pb.ResponseOp_ResponseTxn:
+			if tv.ResponseTxn != nil {
+				kv.unprefixTxnResponse((*clientv3.TxnResponse)(tv.ResponseTxn))
+			}
 		default:
 		}
 	}
@@ -190,3 +183,24 @@ func (kv *kvPrefix) unprefixTxnResponse(resp *clientv3.TxnResponse) {
 func (p *kvPrefix) prefixInterval(key, end []byte) (pfxKey []byte, pfxEnd []byte) {
 	return prefixInterval(p.pfx, key, end)
 }
+
+func (kv *kvPrefix) prefixCmps(cs []clientv3.Cmp) []clientv3.Cmp {
+	newCmps := make([]clientv3.Cmp, len(cs))
+	for i := range cs {
+		newCmps[i] = cs[i]
+		pfxKey, endKey := kv.prefixInterval(cs[i].KeyBytes(), cs[i].RangeEnd)
+		newCmps[i].WithKeyBytes(pfxKey)
+		if len(cs[i].RangeEnd) != 0 {
+			newCmps[i].RangeEnd = endKey
+		}
+	}
+	return newCmps
+}
+
+func (kv *kvPrefix) prefixOps(ops []clientv3.Op) []clientv3.Op {
+	newOps := make([]clientv3.Op, len(ops))
+	for i := range ops {
+		newOps[i] = kv.prefixOp(ops[i])
+	}
+	return newOps
+}

clientv3/op.go

@@ -23,6 +23,7 @@ const (
 	tRange opType = iota + 1
 	tPut
 	tDeleteRange
+	tTxn
 )
 
 var (
@@ -67,10 +68,18 @@ type Op struct {
 	// for put
 	val     []byte
 	leaseID LeaseID
+
+	// txn
+	cmps    []Cmp
+	thenOps []Op
+	elseOps []Op
 }
 
 // accesors / mutators
 
+func (op Op) IsTxn() bool              { return op.t == tTxn }
+func (op Op) Txn() ([]Cmp, []Op, []Op) { return op.cmps, op.thenOps, op.elseOps }
+
 // KeyBytes returns the byte slice holding the Op's key.
 func (op Op) KeyBytes() []byte { return op.key }
 
@@ -113,6 +122,22 @@ func (op Op) toRangeRequest() *pb.RangeRequest {
 	return r
 }
 
+func (op Op) toTxnRequest() *pb.TxnRequest {
+	thenOps := make([]*pb.RequestOp, len(op.thenOps))
+	for i, tOp := range op.thenOps {
+		thenOps[i] = tOp.toRequestOp()
+	}
+	elseOps := make([]*pb.RequestOp, len(op.elseOps))
+	for i, eOp := range op.elseOps {
+		elseOps[i] = eOp.toRequestOp()
+	}
+	cmps := make([]*pb.Compare, len(op.cmps))
+	for i := range op.cmps {
+		cmps[i] = (*pb.Compare)(&op.cmps[i])
+	}
+	return &pb.TxnRequest{Compare: cmps, Success: thenOps, Failure: elseOps}
+}
+
 func (op Op) toRequestOp() *pb.RequestOp {
 	switch op.t {
 	case tRange:
@@ -123,12 +148,27 @@ func (op Op) toRequestOp() *pb.RequestOp {
 	case tDeleteRange:
 		r := &pb.DeleteRangeRequest{Key: op.key, RangeEnd: op.end, PrevKv: op.prevKV}
 		return &pb.RequestOp{Request: &pb.RequestOp_RequestDeleteRange{RequestDeleteRange: r}}
+	case tTxn:
+		return &pb.RequestOp{Request: &pb.RequestOp_RequestTxn{RequestTxn: op.toTxnRequest()}}
 	default:
 		panic("Unknown Op")
 	}
 }
 
 func (op Op) isWrite() bool {
+	if op.t == tTxn {
+		for _, tOp := range op.thenOps {
+			if tOp.isWrite() {
+				return true
+			}
+		}
+		for _, tOp := range op.elseOps {
+			if tOp.isWrite() {
+				return true
+			}
+		}
+		return false
+	}
 	return op.t != tRange
 }
 
@@ -194,6 +234,10 @@ func OpPut(key, val string, opts ...OpOption) Op {
 	return ret
 }
 
+func OpTxn(cmps []Cmp, thenOps []Op, elseOps []Op) Op {
+	return Op{t: tTxn, cmps: cmps, thenOps: thenOps, elseOps: elseOps}
+}
+
 func opWatch(key string, opts ...OpOption) Op {
 	ret := Op{t: tRange, key: []byte(key)}
 	ret.applyOpts(opts)