go-sql-driver/mysql · error

default addr for network '%s' unknown

Error message

default addr for network '%s' unknown

What it means

Error "default addr for network '%s' unknown" thrown in go-sql-driver/mysql.

Source

Thrown at dsn.go:190

func (cfg *Config) normalize() error {
	if cfg.InterpolateParams && cfg.Collation != "" && unsafeCollations[cfg.Collation] {
		return errInvalidDSNUnsafeCollation
	}

	// Set default network if empty
	if cfg.Net == "" {
		cfg.Net = "tcp"
	}

	// Set default address if empty
	if cfg.Addr == "" {
		switch cfg.Net {
		case "tcp":
			cfg.Addr = "127.0.0.1:3306"
		case "unix":
			cfg.Addr = "/tmp/mysql.sock"
		default:
			return errors.New("default addr for network '" + cfg.Net + "' unknown")
		}
	} else if cfg.Net == "tcp" {
		cfg.Addr = ensureHavePort(cfg.Addr)
	}

	if cfg.TLS == nil {
		switch cfg.TLSConfig {
		case "false", "":
			// don't set anything
		case "true":
			cfg.TLS = &tls.Config{}
		case "skip-verify":
			cfg.TLS = &tls.Config{InsecureSkipVerify: true}
		case "preferred":
			cfg.TLS = &tls.Config{InsecureSkipVerify: true}
			cfg.AllowFallbackToPlaintext = true
		default:
			cfg.TLS = getTLSConfigClone(cfg.TLSConfig)

View on GitHub (pinned to 03d76c7e07)

Solutions

1. Provide an explicit addr in the DSN for custom network types, since only 'tcp' and 'unix' have known default addresses.
2. Register a dial function for the custom network with mysql.RegisterDialContext and always specify the address.

Example fix

mysql.RegisterDialContext("myproto", func(ctx context.Context, addr string) (net.Conn, error) {
    var d net.Dialer
    return d.DialContext(ctx, "tcp", addr)
})
dsn := "user:pass@myproto(127.0.0.1:3306)/mydb"

When it happens

Trigger: No address was given in the DSN and the configured network is neither 'tcp' nor 'unix', so the driver cannot pick a default address.

Common situations: Occurs with a custom or misspelled network value, e.g. 'net(foo)/db' without an address. Either spell the network correctly ('tcp' or 'unix') or supply an explicit address: 'user:pass@foo(addr)/db'.

AI-assisted analysis of go-sql-driver/mysql@03d76c7e07 (2026-08-07). Data as JSON: /api/errors/09490d40646982f4. Report an issue: GitHub.