api: add context to connection create

`connection.Connect` and `pool.Connect` no longer return non-working
connection objects. Those functions now accept context as their first
arguments, which user may cancel in process.

`connection.Connect` will block until either the working connection
created (and returned), `opts.MaxReconnects` creation attempts
were made (returns error) or the context is canceled by user
(returns error too).

Closes #136

CHANGELOG.md

@@ -28,6 +28,9 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
   decoded to a varbinary object (#313).
 - Use objects of the Decimal type instead of pointers (#238)
 - Use objects of the Datetime type instead of pointers (#238)
+- `connection.Connect` and `pool.Connect` no longer return non-working 
+  connection objects (#136). Those functions now accept context as their first 
+  arguments, which user may cancel in process.
 
 ### Deprecated
 

README.md

@@ -105,13 +105,15 @@ about what it does.
 package tarantool
 
 import (
+	"context"
 	"fmt"
 	"github.com/tarantool/go-tarantool/v2"
 )
 
 func main() {
 	opts := tarantool.Opts{User: "guest"}
-	conn, err := tarantool.Connect("127.0.0.1:3301", opts)
+	ctx := context.Background()
+	conn, err := tarantool.Connect(ctx, "127.0.0.1:3301", opts)
 	if err != nil {
 		fmt.Println("Connection refused:", err)
 	}

connection.go

@@ -381,10 +381,11 @@ func (opts Opts) Clone() Opts {
 // - If opts.Reconnect is zero (default), then connection either already connected
 // or error is returned.
 //
-// - If opts.Reconnect is non-zero, then error will be returned only if authorization
-// fails. But if Tarantool is not reachable, then it will make an attempt to reconnect later
-// and will not finish to make attempts on authorization failures.
-func Connect(addr string, opts Opts) (conn *Connection, err error) {
+// - If opts.Reconnect is non-zero, then error will be returned if authorization
+// fails, or user has canceled context. If Tarantool is not reachable, then it
+// will make attempts to reconnect and will not finish to make attempts on
+// authorization failures.
+func Connect(ctx context.Context, addr string, opts Opts) (conn *Connection, err error) {
 	conn = &Connection{
 		addr:             addr,
 		requestId:        0,
@@ -432,7 +433,7 @@ func Connect(addr string, opts Opts) (conn *Connection, err error) {
 
 	conn.cond = sync.NewCond(&conn.mutex)
 
-	if err = conn.createConnection(false); err != nil {
+	if err = conn.createConnection(ctx, false); err != nil {
 		ter, ok := err.(Error)
 		if conn.opts.Reconnect <= 0 {
 			return nil, err
@@ -441,15 +442,12 @@ func Connect(addr string, opts Opts) (conn *Connection, err error) {
 			// Reported auth errors immediately.
 			return nil, err
 		} else {
-			// Without SkipSchema it is useless.
-			go func(conn *Connection) {
-				conn.mutex.Lock()
-				defer conn.mutex.Unlock()
-				if err := conn.createConnection(true); err != nil {
-					conn.closeConnection(err, true)
-				}
-			}(conn)
-			err = nil
+			conn.mutex.Lock()
+			defer conn.mutex.Unlock()
+			if err := conn.createConnection(ctx, true); err != nil {
+				conn.closeConnection(err, true)
+				return nil, err
+			}
 		}
 	}
 
@@ -658,7 +656,8 @@ func pack(h *smallWBuf, enc *msgpack.Encoder, reqid uint32,
 	return
 }
 
-func (conn *Connection) createConnection(reconnect bool) (err error) {
+func (conn *Connection) createConnection(ctx context.Context,
+	reconnect bool) (err error) {
 	var reconnects uint
 	for conn.c == nil && conn.state == connDisconnected {
 		now := time.Now()
@@ -679,7 +678,20 @@ func (conn *Connection) createConnection(reconnect bool) (err error) {
 		conn.notify(ReconnectFailed)
 		reconnects++
 		conn.mutex.Unlock()
-		time.Sleep(time.Until(now.Add(conn.opts.Reconnect)))
+
+		timer := time.NewTimer(time.Until(now.Add(conn.opts.Reconnect)))
+	waitLoop:
+		for {
+			select {
+			case <-ctx.Done():
+				err = ClientError{ErrConnectionClosed, "context is canceled"}
+				conn.mutex.Lock()
+				return
+			case <-timer.C:
+				break waitLoop
+			}
+		}
+
 		conn.mutex.Lock()
 	}
 	if conn.state == connClosed {
@@ -731,7 +743,7 @@ func (conn *Connection) reconnectImpl(neterr error, c Conn) {
 	if conn.opts.Reconnect > 0 {
 		if c == conn.c {
 			conn.closeConnection(neterr, false)
-			if err := conn.createConnection(true); err != nil {
+			if err := conn.createConnection(context.Background(), true); err != nil {
 				conn.closeConnection(err, true)
 			}
 		}

crud/example_test.go

@@ -1,6 +1,7 @@
 package crud_test
 
 import (
+	"context"
 	"fmt"
 	"reflect"
 	"time"
@@ -21,7 +22,7 @@ var exampleOpts = tarantool.Opts{
 }
 
 func exampleConnect() *tarantool.Connection {
-	conn, err := tarantool.Connect(exampleServer, exampleOpts)
+	conn, err := tarantool.Connect(context.Background(), exampleServer, exampleOpts)
 	if err != nil {
 		panic("Connection is not established: " + err.Error())
 	}

crud/tarantool_test.go

@@ -1,6 +1,7 @@
 package crud_test
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"os"
@@ -108,7 +109,7 @@ var object = crud.MapObject{
 
 func connect(t testing.TB) *tarantool.Connection {
 	for i := 0; i < 10; i++ {
-		conn, err := tarantool.Connect(server, opts)
+		conn, err := tarantool.Connect(context.Background(), server, opts)
 		if err != nil {
 			t.Fatalf("Failed to connect: %s", err)
 		}

datetime/example_test.go

@@ -9,6 +9,7 @@
 package datetime_test
 
 import (
+	"context"
 	"fmt"
 	"time"
 
@@ -23,7 +24,7 @@ func Example() {
 		User: "test",
 		Pass: "test",
 	}
-	conn, err := tarantool.Connect("127.0.0.1:3013", opts)
+	conn, err := tarantool.Connect(context.Background(), "127.0.0.1:3013", opts)
 	if err != nil {
 		fmt.Printf("Error in connect is %v", err)
 		return

decimal/example_test.go

@@ -9,6 +9,7 @@
 package decimal_test
 
 import (
+	"context"
 	"log"
 	"time"
 
@@ -28,7 +29,7 @@ func Example() {
 		User:          "test",
 		Pass:          "test",
 	}
-	client, err := tarantool.Connect(server, opts)
+	client, err := tarantool.Connect(context.Background(), server, opts)
 	if err != nil {
 		log.Fatalf("Failed to connect: %s", err.Error())
 	}

dial_test.go

@@ -2,6 +2,7 @@ package tarantool_test
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"net"
 	"sync"
@@ -29,9 +30,10 @@ func TestDialer_Dial_error(t *testing.T) {
 		err: errors.New(errMsg),
 	}
 
-	conn, err := tarantool.Connect("any", tarantool.Opts{
-		Dialer: dialer,
-	})
+	conn, err := tarantool.Connect(context.Background(), "any",
+		tarantool.Opts{
+			Dialer: dialer,
+		})
 	assert.Nil(t, conn)
 	assert.ErrorContains(t, err, errMsg)
 }
@@ -73,7 +75,7 @@ func TestDialer_Dial_passedOpts(t *testing.T) {
 	}
 
 	dialer := &mockPassedDialer{}
-	conn, err := tarantool.Connect(addr, tarantool.Opts{
+	conn, err := tarantool.Connect(context.Background(), addr, tarantool.Opts{
 		Dialer:               dialer,
 		Timeout:              opts.IoTimeout,
 		Transport:            opts.Transport,
@@ -203,11 +205,12 @@ func dialIo(t *testing.T,
 	dialer := mockIoDialer{
 		init: init,
 	}
-	conn, err := tarantool.Connect("any", tarantool.Opts{
-		Dialer:     &dialer,
-		Timeout:    1000 * time.Second, // Avoid pings.
-		SkipSchema: true,
-	})
+	conn, err := tarantool.Connect(context.Background(), "any",
+		tarantool.Opts{
+			Dialer:     &dialer,
+			Timeout:    1000 * time.Second, // Avoid pings.
+			SkipSchema: true,
+		})
 	require.Nil(t, err)
 	require.NotNil(t, conn)
 

example_custom_unpacking_test.go

@@ -1,6 +1,7 @@
 package tarantool_test
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"time"
@@ -84,7 +85,7 @@ func Example_customUnpacking() {
 		User:          "test",
 		Pass:          "test",
 	}
-	conn, err := tarantool.Connect(server, opts)
+	conn, err := tarantool.Connect(context.Background(), server, opts)
 	if err != nil {
 		log.Fatalf("Failed to connect: %s", err.Error())
 	}

example_test.go

@@ -19,7 +19,7 @@ type Tuple struct {
 }
 
 func exampleConnect(opts tarantool.Opts) *tarantool.Connection {
-	conn, err := tarantool.Connect(server, opts)
+	conn, err := tarantool.Connect(context.Background(), server, opts)
 	if err != nil {
 		panic("Connection is not established: " + err.Error())
 	}
@@ -38,7 +38,7 @@ func ExampleSslOpts() {
 			CaFile:   "testdata/ca.crt",
 		},
 	}
-	_, err := tarantool.Connect("127.0.0.1:3013", opts)
+	_, err := tarantool.Connect(context.Background(), "127.0.0.1:3013", opts)
 	if err != nil {
 		panic("Connection is not established: " + err.Error())
 	}
@@ -913,12 +913,13 @@ func ExampleFuture_GetIterator() {
 }
 
 func ExampleConnect() {
-	conn, err := tarantool.Connect("127.0.0.1:3013", tarantool.Opts{
-		Timeout:     5 * time.Second,
-		User:        "test",
-		Pass:        "test",
-		Concurrency: 32,
-	})
+	conn, err := tarantool.Connect(context.Background(), "127.0.0.1:3013",
+		tarantool.Opts{
+			Timeout:     5 * time.Second,
+			User:        "test",
+			Pass:        "test",
+			Concurrency: 32,
+		})
 	if err != nil {
 		fmt.Println("No connection available")
 		return
@@ -1081,7 +1082,7 @@ func ExampleConnection_NewPrepared() {
 		User:    "test",
 		Pass:    "test",
 	}
-	conn, err := tarantool.Connect(server, opts)
+	conn, err := tarantool.Connect(context.Background(), server, opts)
 	if err != nil {
 		fmt.Printf("Failed to connect: %s", err.Error())
 	}
@@ -1127,7 +1128,7 @@ func ExampleConnection_NewWatcher() {
 			Features: []tarantool.ProtocolFeature{tarantool.WatchersFeature},
 		},
 	}
-	conn, err := tarantool.Connect(server, opts)
+	conn, err := tarantool.Connect(context.Background(), server, opts)
 	if err != nil {
 		fmt.Printf("Failed to connect: %s\n", err)
 		return