Method dialContext

dialer.go:341–380

(ctx context.Context, network string, addr string)

}

func (d *Dialer) dialContext(ctx context.Context, network string, addr string) (net.Conn, error) {
	address, err := lookupHost(ctx, addr, d.Resolver)
	if err != nil {
		return nil, fmt.Errorf("failed to resolve host: %w", err)
	}

	dial := d.DialFunc
	if dial == nil {
		dial = (&net.Dialer{
			LocalAddr:     d.LocalAddr,
			DualStack:     d.DualStack,
			FallbackDelay: d.FallbackDelay,
			KeepAlive:     d.KeepAlive,
		}).DialContext
	}

	conn, err := dial(ctx, network, address)
	if err != nil {
		return nil, fmt.Errorf("failed to open connection to %s: %w", address, err)
	}

	if d.TLS != nil {
		c := d.TLS
		// If no ServerName is set, infer the ServerName
		// from the hostname we're connecting to.
		if c.ServerName == "" {
			c = d.TLS.Clone()
			// Copied from tls.go in the standard library.
			colonPos := strings.LastIndex(address, ":")
			if colonPos == -1 {
				colonPos = len(address)
			}
			hostname := address[:colonPos]
			c.ServerName = hostname
		}
		return d.connectTLS(ctx, conn, c)
	}

	return conn, nil
}

// DefaultDialer is the default dialer used when none is specified.
var DefaultDialer = &Dialer{