api: support IPROTO_WATCH_ONCE request type

Add support of `IPROTO_WATCH_ONCE` request type.
It works only for Tarantool version >= 3.0.0-alpha1.

Part of #337

CHANGELOG.md

@@ -20,6 +20,8 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
 - Support `fetch_latest_metadata` option for crud requests with metadata (#335)
 - Support `noreturn` option for data change crud requests (#335)
 - Support `crud.schema` request (#336)
+- Support `IPROTO_WATCH_ONCE` request type for Tarantool 
+  version >= 3.0.0-alpha1 (#337)
 
 ### Changed
 

example_test.go

@@ -626,12 +626,13 @@ func ExampleProtocolVersion() {
 		fmt.Println("Connector client protocol feature:", f)
 	}
 	// Output:
-	// Connector client protocol version: 4
+	// Connector client protocol version: 6
 	// Connector client protocol feature: StreamsFeature
 	// Connector client protocol feature: TransactionsFeature
 	// Connector client protocol feature: ErrorExtensionFeature
 	// Connector client protocol feature: WatchersFeature
 	// Connector client protocol feature: PaginationFeature
+	// Connector client protocol feature: WatchOnceFeature
 }
 
 func getTestTxnOpts() tarantool.Opts {
@@ -1230,3 +1231,26 @@ func ExampleConnection_CloseGraceful_force() {
 	// Result:
 	// <nil> connection closed by client (0x4001)
 }
+
+func ExampleWatchOnceRequest() {
+	const key = "foo"
+	const value = "bar"
+
+	// WatchOnce request present in Tarantool since version 3.0
+	isLess, err := test_helpers.IsTarantoolVersionLess(3, 0, 0)
+	if err != nil || isLess {
+		return
+	}
+
+	conn := exampleConnect(opts)
+	defer conn.Close()
+
+	conn.Do(tarantool.NewBroadcastRequest(key).Value(value)).Get()
+
+	resp, err := conn.Do(tarantool.NewWatchOnceRequest(key)).Get()
+	if err != nil {
+		fmt.Printf("Failed to execute the request: %s\n", err)
+	} else {
+		fmt.Println(resp.Data)
+	}
+}

export_test.go

@@ -120,3 +120,9 @@ func RefImplRollbackBody(enc *msgpack.Encoder) error {
 func RefImplIdBody(enc *msgpack.Encoder, protocolInfo ProtocolInfo) error {
 	return fillId(enc, protocolInfo)
 }
+
+// RefImplWatchOnceBody is reference implementation for filling of an watchOnce
+// request's body.
+func RefImplWatchOnceBody(enc *msgpack.Encoder, key string) error {
+	return fillWatchOnce(enc, key)
+}

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/shopspring/decimal v1.3.1
 	github.com/stretchr/testify v1.7.1
-	github.com/tarantool/go-iproto v0.1.0
+	github.com/tarantool/go-iproto v0.1.1-0.20231025103136-cb7894473931
 	github.com/tarantool/go-openssl v0.0.8-0.20231004103608-336ca939d2ca
 	github.com/vmihailenco/msgpack/v5 v5.3.5
 	golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4 // indirect

go.sum

@@ -19,8 +19,8 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1 h1:5TQK59W5E3v0r2duFAb7P95B6hEeOyEnHRa8MjYSMTY=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/tarantool/go-iproto v0.1.0 h1:zHN9AA8LDawT+JBD0/Nxgr/bIsWkkpDzpcMuaNPSIAQ=
-github.com/tarantool/go-iproto v0.1.0/go.mod h1:LNCtdyZxojUed8SbOiYHoc3v9NvaZTB7p96hUySMlIo=
+github.com/tarantool/go-iproto v0.1.1-0.20231025103136-cb7894473931 h1:YrsRc1sDZ6HOZccvM2eJ3Nu2TMBq7NMZMsaT5KCu5qU=
+github.com/tarantool/go-iproto v0.1.1-0.20231025103136-cb7894473931/go.mod h1:LNCtdyZxojUed8SbOiYHoc3v9NvaZTB7p96hUySMlIo=
 github.com/tarantool/go-openssl v0.0.8-0.20231004103608-336ca939d2ca h1:oOrBh73tDDyooIXajfr+0pfnM+89404ClAhJpTTHI7E=
 github.com/tarantool/go-openssl v0.0.8-0.20231004103608-336ca939d2ca/go.mod h1:M7H4xYSbzqpW/ZRBMyH0eyqQBsnhAMfsYk5mv0yid7A=
 github.com/vmihailenco/msgpack/v5 v5.3.5 h1:5gO0H1iULLWGhs2H5tbAHIZTV8/cYafcFOr9znI5mJU=

protocol.go

@@ -12,7 +12,7 @@ import (
 type ProtocolVersion uint64
 
 // ProtocolVersion type stores a Tarantool protocol feature.
-type ProtocolFeature uint64
+type ProtocolFeature iproto.Feature
 
 // ProtocolInfo type aggregates Tarantool protocol version and features info.
 type ProtocolInfo struct {
@@ -52,6 +52,8 @@ const (
 	// PaginationFeature represents support of pagination
 	// (supported by connector).
 	PaginationFeature ProtocolFeature = 4
+	// WatchOnceFeature represents support of WatchOnce request types.
+	WatchOnceFeature ProtocolFeature = 6
 )
 
 // String returns the name of a Tarantool feature.
@@ -68,6 +70,8 @@ func (ftr ProtocolFeature) String() string {
 		return "WatchersFeature"
 	case PaginationFeature:
 		return "PaginationFeature"
+	case WatchOnceFeature:
+		return "WatchOnceFeature"
 	default:
 		return fmt.Sprintf("Unknown feature (code %d)", ftr)
 	}
@@ -79,7 +83,7 @@ var clientProtocolInfo ProtocolInfo = ProtocolInfo{
 	// introduced in master 948e5cd (possible 2.10.5 or 2.11.0).
 	// Support of protocol version on connector side was introduced in
 	// 1.10.0.
-	Version: ProtocolVersion(4),
+	Version: ProtocolVersion(6),
 	// Streams and transactions were introduced in protocol version 1
 	// (Tarantool 2.10.0), in connector since 1.7.0.
 	// Error extension type was introduced in protocol
@@ -88,12 +92,15 @@ var clientProtocolInfo ProtocolInfo = ProtocolInfo{
 	// connector since 1.10.0.
 	// Pagination were introduced in protocol version 4 (Tarantool 2.11.0), in
 	// connector since 1.11.0.
+	// WatchOnce request type was introduces in protocol version 6
+	// (Tarantool 3.0.0), in connector since 2.0.0.
 	Features: []ProtocolFeature{
 		StreamsFeature,
 		TransactionsFeature,
 		ErrorExtensionFeature,
 		WatchersFeature,
 		PaginationFeature,
+		WatchOnceFeature,
 	},
 }
 

protocol_test.go

@@ -32,6 +32,7 @@ func TestFeatureStringRepresentation(t *testing.T) {
 	require.Equal(t, ErrorExtensionFeature.String(), "ErrorExtensionFeature")
 	require.Equal(t, WatchersFeature.String(), "WatchersFeature")
 	require.Equal(t, PaginationFeature.String(), "PaginationFeature")
+	require.Equal(t, WatchOnceFeature.String(), "WatchOnceFeature")
 
 	require.Equal(t, ProtocolFeature(15532).String(), "Unknown feature (code 15532)")
 }

request.go

@@ -166,6 +166,16 @@ func fillPing(enc *msgpack.Encoder) error {
 	return enc.EncodeMapLen(0)
 }
 
+func fillWatchOnce(enc *msgpack.Encoder, key string) error {
+	if err := enc.EncodeMapLen(1); err != nil {
+		return err
+	}
+	if err := enc.EncodeUint(uint64(iproto.IPROTO_EVENT_KEY)); err != nil {
+		return err
+	}
+	return enc.EncodeString(key)
+}
+
 // Ping sends empty request to Tarantool to check connection.
 //
 // Deprecated: the method will be removed in the next major version,
@@ -1354,3 +1364,29 @@ func (req *ExecuteRequest) Context(ctx context.Context) *ExecuteRequest {
 	req.ctx = ctx
 	return req
 }
+
+// WatchOnceRequest synchronously fetches the value currently associated with a
+// specified notification key without subscribing to changes.
+type WatchOnceRequest struct {
+	baseRequest
+	key string
+}
+
+// NewWatchOnceRequest returns a new watchOnceRequest.
+func NewWatchOnceRequest(key string) *WatchOnceRequest {
+	req := new(WatchOnceRequest)
+	req.rtype = iproto.IPROTO_WATCH_ONCE
+	req.key = key
+	return req
+}
+
+// Body fills an msgpack.Encoder with the watchOnce request body.
+func (req *WatchOnceRequest) Body(res SchemaResolver, enc *msgpack.Encoder) error {
+	return fillWatchOnce(enc, req.key)
+}
+
+// Context sets a passed context to the request.
+func (req *WatchOnceRequest) Context(ctx context.Context) *WatchOnceRequest {
+	req.ctx = ctx
+	return req
+}

request_test.go

@@ -196,6 +196,7 @@ func TestRequestsTypes(t *testing.T) {
 		{req: NewRollbackRequest(), rtype: iproto.IPROTO_ROLLBACK},
 		{req: NewIdRequest(validProtocolInfo), rtype: iproto.IPROTO_ID},
 		{req: NewBroadcastRequest(validKey), rtype: iproto.IPROTO_CALL},
+		{req: NewWatchOnceRequest(validKey), rtype: iproto.IPROTO_WATCH_ONCE},
 	}
 
 	for _, test := range tests {
@@ -231,6 +232,7 @@ func TestRequestsAsync(t *testing.T) {
 		{req: NewRollbackRequest(), async: false},
 		{req: NewIdRequest(validProtocolInfo), async: false},
 		{req: NewBroadcastRequest(validKey), async: false},
+		{req: NewWatchOnceRequest(validKey), async: false},
 	}
 
 	for _, test := range tests {
@@ -265,6 +267,7 @@ func TestRequestsCtx_default(t *testing.T) {
 		{req: NewRollbackRequest(), expected: nil},
 		{req: NewIdRequest(validProtocolInfo), expected: nil},
 		{req: NewBroadcastRequest(validKey), expected: nil},
+		{req: NewWatchOnceRequest(validKey), expected: nil},
 	}
 
 	for _, test := range tests {
@@ -300,6 +303,7 @@ func TestRequestsCtx_setter(t *testing.T) {
 		{req: NewRollbackRequest().Context(ctx), expected: ctx},
 		{req: NewIdRequest(validProtocolInfo).Context(ctx), expected: ctx},
 		{req: NewBroadcastRequest(validKey).Context(ctx), expected: ctx},
+		{req: NewWatchOnceRequest(validKey).Context(ctx), expected: ctx},
 	}
 
 	for _, test := range tests {
@@ -823,3 +827,17 @@ func TestBroadcastRequestSetters(t *testing.T) {
 	req := NewBroadcastRequest(validKey).Value(value)
 	assertBodyEqual(t, refBuf.Bytes(), req)
 }
+
+func TestWatchOnceRequestDefaultValues(t *testing.T) {
+	var refBuf bytes.Buffer
+
+	refEnc := msgpack.NewEncoder(&refBuf)
+	err := RefImplWatchOnceBody(refEnc, validKey)
+	if err != nil {
+		t.Errorf("An unexpected RefImplCallBody() error: %q", err.Error())
+		return
+	}
+
+	req := NewWatchOnceRequest(validKey)
+	assertBodyEqual(t, refBuf.Bytes(), req)
+}

tarantool_test.go

@@ -2606,6 +2606,53 @@ func TestConnectionDoSelectRequest(t *testing.T) {
 	testConnectionDoSelectRequestCheck(t, resp, err, false, 10, 1010)
 }
 
+func TestConnectionDoWatchOnceRequest(t *testing.T) {
+	test_helpers.SkipIfWatchOnceUnsupported(t)
+
+	conn := test_helpers.ConnectWithValidation(t, server, opts)
+	defer conn.Close()
+
+	_, err := conn.Do(NewBroadcastRequest("hello").Value("world")).Get()
+	if err != nil {
+		t.Fatalf("Failed to create a broadcast : %s", err.Error())
+	}
+
+	resp, err := conn.Do(NewWatchOnceRequest("hello")).Get()
+	if err != nil {
+		t.Fatalf("Failed to WatchOnce: %s", err.Error())
+	}
+	if resp.Code != OkCode {
+		t.Errorf("Failed to WatchOnce: wrong code returned %d", resp.Code)
+	}
+	if len(resp.Data) < 1 || resp.Data[0] != "world" {
+		t.Errorf("Failed to WatchOnce: wrong value returned %v", resp.Data)
+	}
+}
+
+func TestConnectionDoWatchOnceOnEmptyKey(t *testing.T) {
+	watchOnceNotSupported, err := test_helpers.IsTarantoolVersionLess(3, 0, 0)
+	if err != nil {
+		log.Fatalf("Could not check the Tarantool version")
+	}
+	if watchOnceNotSupported {
+		return
+	}
+
+	conn := test_helpers.ConnectWithValidation(t, server, opts)
+	defer conn.Close()
+
+	resp, err := conn.Do(NewWatchOnceRequest("notexists!")).Get()
+	if err != nil {
+		t.Fatalf("Failed to WatchOnce: %s", err.Error())
+	}
+	if resp.Code != OkCode {
+		t.Errorf("Failed to WatchOnce: wrong code returned %d", resp.Code)
+	}
+	if len(resp.Data) > 0 {
+		t.Errorf("Failed to WatchOnce: wrong value returned %v", resp.Data)
+	}
+}
+
 func TestConnectionDoSelectRequest_fetch_pos(t *testing.T) {
 	test_helpers.SkipIfPaginationUnsupported(t)
 
@@ -3247,13 +3294,14 @@ func TestConnectionProtocolInfoSupported(t *testing.T) {
 	require.Equal(t,
 		clientProtocolInfo,
 		ProtocolInfo{
-			Version: ProtocolVersion(4),
+			Version: ProtocolVersion(6),
 			Features: []ProtocolFeature{
 				StreamsFeature,
 				TransactionsFeature,
 				ErrorExtensionFeature,
 				WatchersFeature,
 				PaginationFeature,
+				WatchOnceFeature,
 			},
 		})
 
@@ -3364,13 +3412,14 @@ func TestConnectionProtocolInfoUnsupported(t *testing.T) {
 	require.Equal(t,
 		clientProtocolInfo,
 		ProtocolInfo{
-			Version: ProtocolVersion(4),
+			Version: ProtocolVersion(6),
 			Features: []ProtocolFeature{
 				StreamsFeature,
 				TransactionsFeature,
 				ErrorExtensionFeature,
 				WatchersFeature,
 				PaginationFeature,
+				WatchOnceFeature,
 			},
 		})
 

test_helpers/utils.go

@@ -192,6 +192,14 @@ func SkipIfPaginationUnsupported(t *testing.T) {
 	SkipIfFeatureUnsupported(t, "pagination", 2, 11, 0)
 }
 
+// SkipIfWatchOnceUnsupported skips test run if Tarantool without WatchOnce
+// request type is used.
+func SkipIfWatchOnceUnsupported(t *testing.T) {
+	t.Helper()
+
+	SkipIfFeatureUnsupported(t, "watch once", 3, 0, 0)
+}
+
 // CheckEqualBoxErrors checks equivalence of tarantool.BoxError objects.
 //
 // Tarantool errors are not comparable by nature: