client: use go-winio.DialPipe directly

The go-connections package implementation is only a shallow wrapper
around go-winio for named pipes; use the go-winio implementation
directly.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

client/client.go

@@ -463,7 +463,9 @@ func (cli *Client) dialer() func(context.Context) (net.Conn, error) {
 		case "unix":
 			return net.Dial(cli.proto, cli.addr)
 		case "npipe":
-			return sockets.DialPipe(cli.addr, 32*time.Second)
+			ctx, cancel := context.WithTimeout(ctx, 32*time.Second)
+			defer cancel()
+			return dialPipeContext(ctx, cli.addr)
 		default:
 			if tlsConfig := cli.tlsConfig(); tlsConfig != nil {
 				return tls.Dial(cli.proto, cli.addr, tlsConfig)

client/client_unix.go

@@ -2,6 +2,17 @@
 
 package client
 
+import (
+	"context"
+	"net"
+	"syscall"
+)
+
 // DefaultDockerHost defines OS-specific default host if the DOCKER_HOST
 // (EnvOverrideHost) environment variable is unset or empty.
 const DefaultDockerHost = "unix:///var/run/docker.sock"
+
+// dialPipeContext connects to a Windows named pipe. It is not supported on non-Windows.
+func dialPipeContext(_ context.Context, _ string) (net.Conn, error) {
+	return nil, syscall.EAFNOSUPPORT
+}

client/client_windows.go

@@ -1,5 +1,17 @@
 package client
 
+import (
+	"context"
+	"net"
+
+	"github.com/Microsoft/go-winio"
+)
+
 // DefaultDockerHost defines OS-specific default host if the DOCKER_HOST
 // (EnvOverrideHost) environment variable is unset or empty.
 const DefaultDockerHost = "npipe:////./pipe/docker_engine"
+
+// dialPipeContext connects to a Windows named pipe. It is not supported on non-Windows.
+func dialPipeContext(ctx context.Context, addr string) (net.Conn, error) {
+	return winio.DialPipeContext(ctx, addr)
+}