[BUG] TCP Connect does not error if connection not able to be created about workers-rs HOT 8 CLOSED

Yep, I think it would be reasonable to add that to the Rust API. Also looks like we need to add it to our JavaScript docs.

from workers-rs.

This matches the behavior of the JavaScript API, which returns from connect immediately (it is not a Promise), and thus does not indicate whether the connection has been established with the remote server. Errors are then propagated when trying to read / write from the socket.

from workers-rs.

This matches the behavior of the JavaScript API, which returns from connect immediately (it is not a Promise), and thus does not indicate whether the connection has been established with the remote server. Errors are then propagated when trying to read / write from the socket.

So thats generally fine, but I was also seeing a write not fail on a socket that didn't actually have an open port, unless I did this wrong somehow.

    let mut socket = Socket::builder()
        .secure_transport(SecureTransport::Off)
        .connect(&connecting_ip, port)
        .map_err(|_| worker::Error::from("Could not create socket"))?;

    socket
        .write(b"GET / HTTP/1.0\r\nHost: example.com\r\n\r\n")
        .await
        .map_err(|_| worker::Error::from("Could not write to socket"))?;

This write doesn't fail for me, even on a closed port, and it sounds like it should err?

from workers-rs.

Does reading return an error? I think it should error, but I will have to check the JavaScript behavior.

from workers-rs.

Reading returns an error in most cases. There are certain types of applications where this doesn't seem to be particularly reliable though.

I did some testing in node earlier, and while the socket.connect call itself does not return a promise, you are able to attach event listeners to events like connect, timeout, and error which enable getting at this info more reliably than writing then trying to read. It would be nice to have some way to get at this in Rust (and I was tinkering a bit in JS with workers, and wasn't able to get it to work in that context either). Node test code here https://gist.github.com/cmmarslender/145a929163d8f3501490bf00bed2e993

I think my current rust implementation covers most of the cases I need it to cover, but it would be nice if this could eventually work with just connect and an error there, or attaching an on connect/error/timeout handler, or perhaps some other solution, that doesn't require having to write and read.

from workers-rs.

@dom96 thoughts on this behavior?

from workers-rs.

I did some testing in node earlier, and while the socket.connect call itself does not return a promise, you are able to attach event listeners to events like connect, timeout, and error which enable getting at this info more reliably than writing then trying to read

We now have an opened promise that can be used for this purpose. It should get rejected if the connection fails to be opened and that shouldn't require any reads/writes to happen.

As for the write not failing, I believe that is expected (for the same reason connect doesn't return a promise which waits for the connection result) and the error ends up in the closed promise instead.

from workers-rs.

I did some testing in node earlier, and while the socket.connect call itself does not return a promise, you are able to attach event listeners to events like connect, timeout, and error which enable getting at this info more reliably than writing then trying to read

We now have an opened promise that can be used for this purpose. It should get rejected if the connection fails to be opened and that shouldn't require any reads/writes to happen.

As for the write not failing, I believe that is expected (for the same reason connect doesn't return a promise which waits for the connection result) and the error ends up in the closed promise instead.

is it possible to get at the opened promise in some way from Rust, and if so, are there docs or an example on this somewhere? I haven't seen anything, but may be looking in the wrong places.

from workers-rs.