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,
@@ -432,25 +433,8 @@ func Connect(addr string, opts Opts) (conn *Connection, err error) {
 
 	conn.cond = sync.NewCond(&conn.mutex)
 
-	if err = conn.createConnection(false); err != nil {
-		ter, ok := err.(Error)
-		if conn.opts.Reconnect <= 0 {
-			return nil, err
-		} else if ok && (ter.Code == iproto.ER_NO_SUCH_USER ||
-			ter.Code == iproto.ER_CREDS_MISMATCH) {
-			// 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
-		}
+	if err = conn.createConnection(ctx, false); err != nil {
+		return nil, err
 	}
 
 	go conn.pinger()
@@ -534,18 +518,19 @@ func (conn *Connection) cancelFuture(fut *Future, err error) {
 	}
 }
 
-func (conn *Connection) dial() (err error) {
+func (conn *Connection) dial(ctx context.Context) (err error) {
 	opts := conn.opts
 	dialTimeout := opts.Reconnect / 2
 	if dialTimeout == 0 {
 		dialTimeout = 500 * time.Millisecond
 	} else if dialTimeout > 5*time.Second {
 		dialTimeout = 5 * time.Second
 	}
+	nestedCtx, cancel := context.WithTimeout(ctx, dialTimeout)
+	defer cancel()
 
 	var c Conn
-	c, err = conn.opts.Dialer.Dial(conn.addr, DialOpts{
-		DialTimeout:      dialTimeout,
+	c, err = conn.opts.Dialer.Dial(nestedCtx, conn.addr, DialOpts{
 		IoTimeout:        opts.Timeout,
 		Transport:        opts.Transport,
 		Ssl:              opts.Ssl,
@@ -658,34 +643,46 @@ 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) error {
 	var reconnects uint
 	for conn.c == nil && conn.state == connDisconnected {
 		now := time.Now()
-		err = conn.dial()
+		err := conn.dial(ctx)
 		if err == nil || !reconnect {
 			if err == nil {
 				conn.notify(Connected)
 			}
-			return
+			return err
 		}
 		if conn.opts.MaxReconnects > 0 && reconnects > conn.opts.MaxReconnects {
 			conn.opts.Logger.Report(LogLastReconnectFailed, conn, err)
-			err = ClientError{ErrConnectionClosed, "last reconnect failed"}
 			// mark connection as closed to avoid reopening by another goroutine
-			return
+			return ClientError{ErrConnectionClosed, "last reconnect failed"}
 		}
 		conn.opts.Logger.Report(LogReconnectFailed, conn, reconnects, err)
 		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():
+				conn.mutex.Lock()
+				return ClientError{ErrConnectionClosed, "context is canceled"}
+			case <-timer.C:
+				break waitLoop
+			}
+		}
+
 		conn.mutex.Lock()
 	}
 	if conn.state == connClosed {
-		err = ClientError{ErrConnectionClosed, "using closed connection"}
+		return ClientError{ErrConnectionClosed, "using closed connection"}
 	}
-	return
+	return nil
 }
 
 func (conn *Connection) closeConnection(neterr error, forever bool) (err error) {
@@ -731,7 +728,7 @@ 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.go

@@ -3,6 +3,7 @@ package tarantool
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -56,8 +57,6 @@ type Conn interface {
 
 // DialOpts is a way to configure a Dial method to create a new Conn.
 type DialOpts struct {
-	// DialTimeout is a timeout for an initial network dial.
-	DialTimeout time.Duration
 	// IoTimeout is a timeout per a network read/write.
 	IoTimeout time.Duration
 	// Transport is a connect transport type.
@@ -86,7 +85,7 @@ type DialOpts struct {
 type Dialer interface {
 	// Dial connects to a Tarantool instance to the address with specified
 	// options.
-	Dial(address string, opts DialOpts) (Conn, error)
+	Dial(ctx context.Context, address string, opts DialOpts) (Conn, error)
 }
 
 type tntConn struct {
@@ -104,11 +103,11 @@ type TtDialer struct {
 
 // Dial connects to a Tarantool instance to the address with specified
 // options.
-func (t TtDialer) Dial(address string, opts DialOpts) (Conn, error) {
+func (t TtDialer) Dial(ctx context.Context, address string, opts DialOpts) (Conn, error) {
 	var err error
 	conn := new(tntConn)
 
-	if conn.net, err = dial(address, opts); err != nil {
+	if conn.net, err = dial(ctx, address, opts); err != nil {
 		return nil, fmt.Errorf("failed to dial: %w", err)
 	}
 
@@ -199,13 +198,14 @@ func (c *tntConn) ProtocolInfo() ProtocolInfo {
 }
 
 // dial connects to a Tarantool instance.
-func dial(address string, opts DialOpts) (net.Conn, error) {
+func dial(ctx context.Context, address string, opts DialOpts) (net.Conn, error) {
 	network, address := parseAddress(address)
 	switch opts.Transport {
 	case dialTransportNone:
-		return net.DialTimeout(network, address, opts.DialTimeout)
+		dialer := net.Dialer{}
+		return dialer.DialContext(ctx, network, address)
 	case dialTransportSsl:
-		return sslDialTimeout(network, address, opts.DialTimeout, opts.Ssl)
+		return sslDialContext(ctx, network, address, opts.Ssl)
 	default:
 		return nil, fmt.Errorf("unsupported transport type: %s", opts.Transport)
 	}

dial_test.go

@@ -2,6 +2,7 @@ package tarantool_test
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"net"
 	"sync"
@@ -18,7 +19,7 @@ type mockErrorDialer struct {
 	err error
 }
 
-func (m mockErrorDialer) Dial(address string,
+func (m mockErrorDialer) Dial(ctx context.Context, address string,
 	opts tarantool.DialOpts) (tarantool.Conn, error) {
 	return nil, m.err
 }
@@ -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)
 }
@@ -41,7 +43,7 @@ type mockPassedDialer struct {
 	opts    tarantool.DialOpts
 }
 
-func (m *mockPassedDialer) Dial(address string,
+func (m *mockPassedDialer) Dial(ctx context.Context, address string,
 	opts tarantool.DialOpts) (tarantool.Conn, error) {
 	m.address = address
 	m.opts = opts
@@ -51,9 +53,8 @@ func (m *mockPassedDialer) Dial(address string,
 func TestDialer_Dial_passedOpts(t *testing.T) {
 	const addr = "127.0.0.1:8080"
 	opts := tarantool.DialOpts{
-		DialTimeout: 500 * time.Millisecond,
-		IoTimeout:   2,
-		Transport:   "any",
+		IoTimeout: 2,
+		Transport: "any",
 		Ssl: tarantool.SslOpts{
 			KeyFile:  "a",
 			CertFile: "b",
@@ -73,7 +74,9 @@ func TestDialer_Dial_passedOpts(t *testing.T) {
 	}
 
 	dialer := &mockPassedDialer{}
-	conn, err := tarantool.Connect(addr, tarantool.Opts{
+	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
+	defer cancel()
+	conn, err := tarantool.Connect(ctx, addr, tarantool.Opts{
 		Dialer:               dialer,
 		Timeout:              opts.IoTimeout,
 		Transport:            opts.Transport,
@@ -187,7 +190,7 @@ func newMockIoConn() *mockIoConn {
 	return conn
 }
 
-func (m *mockIoDialer) Dial(address string,
+func (m *mockIoDialer) Dial(ctx context.Context, address string,
 	opts tarantool.DialOpts) (tarantool.Conn, error) {
 	m.conn = newMockIoConn()
 	if m.init != nil {
@@ -203,11 +206,12 @@ 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())
 	}