From 36ea1e072959ff4c683e0c05328565f2c8992ab2 Mon Sep 17 00:00:00 2001 From: Sebastian Harl Date: Sun, 22 Feb 2015 00:16:49 +0100 Subject: [PATCH] client: Try to reconnect after read/write failures. --- client/client.go | 105 ++++++++++++++++++++++++++++++++++------------- 1 file changed, 77 insertions(+), 28 deletions(-) diff --git a/client/client.go b/client/client.go index 34a0434..fcb5d8d 100644 --- a/client/client.go +++ b/client/client.go @@ -71,7 +71,39 @@ import ( // messages, the communication with the server will usually happen // sequentially. type Conn struct { - c net.Conn + c net.Conn + network, addr, user string +} + +func (c *Conn) connect() (err error) { + if c.c, err = net.Dial(c.network, c.addr); err != nil { + return err + } + defer func() { + if err != nil { + c.Close() + } + }() + + m := &proto.Message{ + Type: proto.ConnectionStartup, + Raw: []byte(c.user), + } + if err := c.Send(m); err != nil { + return err + } + + m, err = c.Receive() + if err != nil { + return err + } + if m.Type == proto.ConnectionError { + return fmt.Errorf("failed to startup session: %s", string(m.Raw)) + } + if m.Type != proto.ConnectionOK { + return fmt.Errorf("failed to startup session: unsupported") + } + return nil } // Connect sets up a client connection to a SysDB server instance at the @@ -88,45 +120,46 @@ func Connect(addr, user string) (*Conn, error) { network = "unix" } - c := &Conn{} - var err error - if c.c, err = net.Dial(network, addr); err != nil { - return nil, err - } - - m := &proto.Message{ - Type: proto.ConnectionStartup, - Raw: []byte(user), - } - if err := c.Send(m); err != nil { - return nil, err - } - - m, err = c.Receive() - if err != nil { + c := &Conn{network: network, addr: addr, user: user} + if err := c.connect(); err != nil { return nil, err } - if m.Type == proto.ConnectionError { - return nil, fmt.Errorf("failed to startup session: %s", string(m.Raw)) - } - if m.Type != proto.ConnectionOK { - return nil, fmt.Errorf("failed to startup session: unsupported") - } return c, nil } // Close closes the client connection. // // Any blocked Send or Receive operations will be unblocked and return errors. -func (c Conn) Close() { c.c.Close() } +func (c *Conn) Close() { + if c.c == nil { + return + } + c.c.Close() + c.c = nil +} // Send sends the specified raw message to the server. // // Send operations block until the full message could be written to the // underlying sockets. This ensures that server and client don't get out of // sync. -func (c Conn) Send(m *proto.Message) error { - return proto.Write(c.c, m) +func (c *Conn) Send(m *proto.Message) error { + var err error + if c.c != nil { + err = proto.Write(c.c, m) + if err == nil { + return nil + } + c.Close() + } + + // Try to reconnect. + if e := c.connect(); e == nil { + return proto.Write(c.c, m) + } else if err == nil { + err = e + } + return err } // Receive waits for a reply from the server and returns the raw message. @@ -134,8 +167,24 @@ func (c Conn) Send(m *proto.Message) error { // Receive operations block until a full message could be read from the // underlying socket. This ensures that server and client don't get out of // sync. -func (c Conn) Receive() (*proto.Message, error) { - return proto.Read(c.c) +func (c *Conn) Receive() (*proto.Message, error) { + var err error + if c.c != nil { + var m *proto.Message + m, err = proto.Read(c.c) + if err == nil { + return m, err + } + c.Close() + } + + // Try to reconnect. + if e := c.connect(); e == nil { + return proto.Read(c.c) + } else if err == nil { + err = e + } + return nil, err } // vim: set tw=78 sw=4 sw=4 noexpandtab : -- 2.30.2