func()

in go/mqtt/connect.go [163:248]
61 lines of code
13 McCabe index (conditional complexity)

func (c *SessionClient) connect(
	ctx context.Context,
	reconnect bool,
) (*paho.Connack, error) {
	attempt := c.conn.Attempt()

	conn, err := c.connectionProvider(ctx)
	if err != nil {
		return nil, err
	}

	var auther paho.Auther
	if c.options.Auth != nil {
		auther = &pahoAuther{c}
	}

	pahoClient := paho.NewClient(paho.ClientConfig{
		ClientID:    c.clientID,
		Session:     c.session,
		Conn:        conn,
		AuthHandler: auther,

		// Set Paho's packet timeout to the maximum possible value to
		// effectively disable it. We can still control any timeouts through the
		// contexts we pass into Paho.
		PacketTimeout: math.MaxInt64,

		// Disable automatic acking in Paho. The session client will manage acks
		// instead.
		EnableManualAcknowledgment: true,

		OnPublishReceived: []func(paho.PublishReceived) (bool, error){
			// Add 1 to the conn count for this because this listener is
			// effective AFTER the connection succeeds.
			c.makeOnPublishReceived(ctx, attempt),
		},
		OnServerDisconnect: func(d *paho.Disconnect) {
			if isFatalDisconnectReasonCode(d.ReasonCode) {
				c.conn.Disconnect(attempt, &FatalDisconnectError{d.ReasonCode})
			} else {
				c.conn.Disconnect(attempt, &DisconnectError{d.ReasonCode})
			}
		},

		OnClientError: func(err error) {
			c.conn.Disconnect(attempt, err)
		},
	})

	connect, err := c.buildConnectPacket(ctx, reconnect)
	if err != nil {
		return nil, err
	}

	c.log.Packet(ctx, "connect", connect)
	connack, err := pahoClient.Connect(ctx, connect)
	c.log.Packet(ctx, "connack", connack)

	switch {
	case connack == nil:
		// This assumes that all errors returned by Paho's connect method
		// without a CONNACK are non-fatal.
		return nil, err

	case isFatalConnackReasonCode(connack.ReasonCode):
		return nil, &FatalConnackError{connack.ReasonCode}

	case connack.ReasonCode >= 80:
		return nil, &ConnackError{connack.ReasonCode}

	case reconnect && !connack.SessionPresent:
		c.forceDisconnect(ctx, pahoClient)
		return nil, &SessionLostError{}

	default:
		if err := c.conn.Connect(pahoClient); err != nil {
			return nil, err
		}
		if c.options.Auth != nil && connack.Properties.AuthMethod == "" {
			// Ensure the auth provider is notified of success even if the MQTT
			// server fails to echo the auth method.
			c.options.Auth.AuthSuccess(c.requestReauth)
		}
		return connack, nil
	}
}