Function ConnectConfig

pgconn/pgconn.go:142–175

Connect establishes a connection to a PostgreSQL server using config. config must have been constructed with [ParseConfig]. ctx can be used to cancel a connect attempt. If config.Fallbacks are present they will sequentially be tried in case of error establishing network connection. An authenticatio

(ctx context.Context, config *Config)

// authentication error will terminate the chain of attempts (like libpq:
// https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS) and be returned as the error.
func ConnectConfig(ctx context.Context, config *Config) (*PgConn, error) {
	// Default values are set in ParseConfig. Enforce initial creation by ParseConfig rather than setting defaults from
	// zero values.
	if !config.createdByParseConfig {
		panic("config must be created by ParseConfig")
	}

	var allErrors []error

	connectConfigs, errs := buildConnectOneConfigs(ctx, config)
	if len(errs) > 0 {
		allErrors = append(allErrors, errs...)
	}

	if len(connectConfigs) == 0 {
		return nil, &ConnectError{Config: config, err: fmt.Errorf("hostname resolving error: %w", errors.Join(allErrors...))}
	}

	pgConn, errs := connectPreferred(ctx, config, connectConfigs)
	if len(errs) > 0 {
		allErrors = append(allErrors, errs...)
		return nil, &ConnectError{Config: config, err: errors.Join(allErrors...)}
	}

	if config.AfterConnect != nil {
		err := config.AfterConnect(ctx, pgConn)
		if err != nil {
			pgConn.conn.Close()
			return nil, &ConnectError{Config: config, err: fmt.Errorf("AfterConnect error: %w", err)}
		}
	}

	return pgConn, nil
}

// buildConnectOneConfigs resolves hostnames and builds a list of connectOneConfigs to try connecting to. It returns a
// slice of successfully resolved connectOneConfigs and a slice of errors. It is possible for both slices to contain