feature request - Support localhost in address

[gaocegege]

Behavior

$ engula journal run localhost:8888 --mem
error: Invalid value for '<ADDR>': invalid IP address syntax

Expected

Just works as 127.0.0.1:8888

Version

6c59de2

[tisonkun]

It seems Rust's SocketAddr fails to parse "localhost:8888".

            let mut groups = [0; 4];

            for (i, slot) in groups.iter_mut().enumerate() {
                *slot = p.read_separator('.', i, |p| {
                    // Disallow octal number in IP string.
                    // https://tools.ietf.org/html/rfc6943#section-3.1.1
                    p.read_number(10, Some(3), false)
                })?;
            }

            Some(groups.into())

only accept ddd.ddd.ddd.ddd. Thus when Clap tries to parse the string into SocketAddr, it fails with the message above.

[gaocegege]

Yeah, it is hardcoded to only support IP.

Maybe we should use the struct like inetaddress to support hostname.

[Xuanwo]

ToSocketAddrs has been implemented for &str, so it's Ok to use "localhost:12345".to_socket_addrs()

Take https://doc.rust-lang.org/std/net/trait.ToSocketAddrs.html#examples for reference.

For engula, I prefer to use String in command args.

[tisonkun]

@Xuanwo thanks for investigation! I learn from how we previous tested grpc implement and prepared a patch.