api: support IPROTO_WATCH_ONCE request type

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

Closes #337

Author: DerekBum

CHANGELOG.md

@@ -20,6 +20,7 @@ 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 (#337)
 
 ### Changed
 

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=

request.go

@@ -1354,3 +1354,36 @@ 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
+	ctx context.Context
+}
+
+// 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 {
+	if err := enc.EncodeMapLen(1); err != nil {
+		return err
+	}
+	if err := enc.EncodeUint(uint64(iproto.IPROTO_EVENT_KEY)); err != nil {
+		return err
+	}
+	return enc.Encode(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 {

tarantool_test.go

@@ -2606,6 +2606,59 @@ func TestConnectionDoSelectRequest(t *testing.T) {
 	testConnectionDoSelectRequestCheck(t, resp, err, false, 10, 1010)
 }
 
+func TestConnectionDoWatchOnceRequest(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()
+
+	_, 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)