func()

in internal/proxy/proxy.go [937:1001]

• 60 lines of code
• 14 McCabe index (conditional complexity)

func (c *Client) proxyConn(inst string, client, server net.Conn) {
	// only allow the first side to give an error for terminating a connection
	var o sync.Once
	cleanup := func(errDesc string, isErr bool) {
		o.Do(func() {
			_ = client.Close()
			_ = server.Close()
			if isErr {
				c.logger.Errorf(errDesc)
			} else {
				c.logger.Infof(errDesc)
			}
		})
	}

	// copy bytes from client to server
	go func() {
		buf := make([]byte, 8*1024) // 8kb
		for {
			n, cErr := client.Read(buf)
			var sErr error
			if n > 0 {
				_, sErr = server.Write(buf[:n])
			}
			switch {
			case cErr == io.EOF:
				cleanup(fmt.Sprintf("[%s] client closed the connection", inst), false)
				return
			case cErr != nil:
				cleanup(fmt.Sprintf("[%s] connection aborted - error reading from client: %v", inst, cErr), true)
				return
			case sErr == io.EOF:
				cleanup(fmt.Sprintf("[%s] instance closed the connection", inst), false)
				return
			case sErr != nil:
				cleanup(fmt.Sprintf("[%s] connection aborted - error writing to instance: %v", inst, sErr), true)
				return
			}
		}
	}()

	// copy bytes from server to client
	buf := make([]byte, 8*1024) // 8kb
	for {
		n, sErr := server.Read(buf)
		var cErr error
		if n > 0 {
			_, cErr = client.Write(buf[:n])
		}
		switch {
		case sErr == io.EOF:
			cleanup(fmt.Sprintf("[%s] instance closed the connection", inst), false)
			return
		case sErr != nil:
			cleanup(fmt.Sprintf("[%s] connection aborted - error reading from instance: %v", inst, sErr), true)
			return
		case cErr == io.EOF:
			cleanup(fmt.Sprintf("[%s] client closed the connection", inst), false)
			return
		case cErr != nil:
			cleanup(fmt.Sprintf("[%s] connection aborted - error writing to client: %v", inst, cErr), true)
			return
		}
	}
}