Function connectOne

pgconn/pgconn.go:313–541

connectOne makes one connection attempt to a single host.

(ctx context.Context, config *Config, connectConfig *connectOneConfig,
	ignoreNotPreferredErr bool,
)

// connectOne makes one connection attempt to a single host.
func connectOne(ctx context.Context, config *Config, connectConfig *connectOneConfig,
	ignoreNotPreferredErr bool,
) (*PgConn, error) {
	pgConn := new(PgConn)
	pgConn.config = config
	pgConn.cleanupDone = make(chan struct{})
	pgConn.customData = make(map[string]any)

	var err error

	newPerDialConnectError := func(msg string, err error) *perDialConnectError {
		err = normalizeTimeoutError(ctx, err)
		e := &perDialConnectError{address: connectConfig.address, originalHostname: connectConfig.originalHostname, err: fmt.Errorf("%s: %w", msg, err)}
		return e
	}

	maxProtocolVersion, err := parseProtocolVersion(config.MaxProtocolVersion)
	if err != nil {
		return nil, newPerDialConnectError("invalid max_protocol_version", err)
	}
	minProtocolVersion, err := parseProtocolVersion(config.MinProtocolVersion)
	if err != nil {
		return nil, newPerDialConnectError("invalid min_protocol_version", err)
	}

	pgConn.conn, err = config.DialFunc(ctx, connectConfig.network, connectConfig.address)
	if err != nil {
		return nil, newPerDialConnectError("dial error", err)
	}

	if connectConfig.tlsConfig != nil {
		pgConn.contextWatcher = ctxwatch.NewContextWatcher(&DeadlineContextWatcherHandler{Conn: pgConn.conn})
		pgConn.contextWatcher.Watch(ctx)
		var (
			tlsConn net.Conn
			err     error
		)
		if config.SSLNegotiation == "direct" {
			tlsConn = tls.Client(pgConn.conn, connectConfig.tlsConfig)
		} else {
			tlsConn, err = startTLS(pgConn.conn, connectConfig.tlsConfig)
		}
		pgConn.contextWatcher.Unwatch() // Always unwatch `netConn` after TLS.
		if err != nil {
			pgConn.conn.Close()
			return nil, newPerDialConnectError("tls error", err)
		}

		pgConn.conn = tlsConn
		pgConn.tlsConfig = connectConfig.tlsConfig
	}

	if config.AfterNetConnect != nil {
		pgConn.conn, err = config.AfterNetConnect(ctx, config, pgConn.conn)
		if err != nil {
			pgConn.conn.Close()
			return nil, newPerDialConnectError("AfterNetConnect failed", err)
		}