[#205] v2/client: Replace WithGRPCDialContext option with WithDialTimeout

There is a need to set dial timeout in v2 client that is used in case of
internal connection opening. Add DialTimeout option constructor to support
this feature. Remove unused and no longer needed WithGRPCDialContext
function.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

v2/client/options.go

@@ -3,6 +3,7 @@ package client
 import (
 	"context"
 	"net"
+	"time"
 
 	"google.golang.org/grpc"
 )
@@ -15,24 +16,26 @@ type cfg struct {
 	conn net.Conn
 
 	gRPC cfgGRPC
+
+	dialTimeout time.Duration
 }
 
 type cfgGRPC struct {
-	dialCtx context.Context
-
 	dialOpts []grpc.DialOption
 
 	conn *grpc.ClientConn
 }
 
+const defaultDialTimeout = 5 * time.Second
+
 func defaultCfg() *cfg {
 	return &cfg{
 		gRPC: cfgGRPC{
-			dialCtx: context.Background(),
 			dialOpts: []grpc.DialOption{
 				grpc.WithInsecure(),
 			},
 		},
+		dialTimeout: defaultDialTimeout,
 	}
 }
 
@@ -58,7 +61,11 @@ func NewGRPCClientConn(opts ...Option) (*grpc.ClientConn, error) {
 			)
 		}
 
-		cfg.gRPC.conn, err = grpc.DialContext(cfg.gRPC.dialCtx, cfg.addr, cfg.gRPC.dialOpts...)
+		dialCtx, cancel := context.WithTimeout(context.Background(), cfg.dialTimeout)
+
+		cfg.gRPC.conn, err = grpc.DialContext(dialCtx, cfg.addr, cfg.gRPC.dialOpts...)
+
+		cancel()
 		if err != nil {
 			return nil, err
 		}
@@ -83,10 +90,10 @@ func WithNetConn(v net.Conn) Option {
 	}
 }
 
-func WithGRPCDialContext(v context.Context) Option {
+func WithDialTimeout(v time.Duration) Option {
 	return func(c *cfg) {
-		if v != nil {
+		if v > 0 {
-			c.gRPC.dialCtx = v
+			c.dialTimeout = v
 		}
 	}
 }