fix dial error when clean up a dead shim

Signed-off-by: lifubang <lifubang@acmcoder.com>

pkg/ttrpcutil/client.go

@@ -50,14 +50,8 @@ func NewClient(address string, opts ...ttrpc.ClientOpts) (*Client, error) {
 		return client, nil
 	}
 
-	client, err := connector()
-	if err != nil {
-		return nil, err
-	}
-
 	return &Client{
 		connector: connector,
-		client:    client,
 	}, nil
 }
 
@@ -74,6 +68,12 @@ func (c *Client) Reconnect() error {
 		return errors.New("client is closed")
 	}
 
+	if c.client != nil {
+		if err := c.client.Close(); err != nil {
+			return err
+		}
+	}
+
 	client, err := c.connector()
 	if err != nil {
 		return err
@@ -84,16 +84,26 @@ func (c *Client) Reconnect() error {
 }
 
 // EventsService creates an EventsService client
-func (c *Client) EventsService() v1.EventsService {
-	return v1.NewEventsClient(c.Client())
+func (c *Client) EventsService() (v1.EventsService, error) {
+	client, err := c.Client()
+	if err != nil {
+		return nil, err
+	}
+	return v1.NewEventsClient(client), nil
 }
 
 // Client returns the underlying TTRPC client object
-func (c *Client) Client() *ttrpc.Client {
+func (c *Client) Client() (*ttrpc.Client, error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-
-	return c.client
+	if c.client == nil {
+		client, err := c.connector()
+		if err != nil {
+			return nil, err
+		}
+		c.client = client
+	}
+	return c.client, nil
 }
 
 // Close closes the clients TTRPC connection to containerd
@@ -102,5 +112,8 @@ func (c *Client) Close() error {
 	defer c.mu.Unlock()
 
 	c.closed = true
-	return c.client.Close()
+	if c.client != nil {
+		return c.client.Close()
+	}
+	return nil
 }