Re-enable C# arrow flight integration test

[alamb]

Which issue does this PR close?

Closes #6577

Rationale for this change

This test was turned off in #6598 as it was failing

What changes are included in this PR?

Implement @adamreeve 's suggestion (❤️ ) from apache/arrow#44377 (comment)

1. Change address sent in FlightInfo to be localhost rather than 0.0.0.0
2. Re-enable the integration test

Note that @adamreeve says this might be something the C# client should handle, so maybe we should take a different approach 🤔

But I'm not 100% sure this isn't something the C# client should handle, given the other clients seem OK with it.

Are there any user-facing changes?

No this is testing only

[alamb]

@CurtHagenlocher also mentions maybe the C# should be changed rather than the rust test harness: apache/arrow#44377 (comment)

[tustvold]

FWIW listen_on should probably be returning the resolved socket address.

Also localhost may not work on machines with dual stack IPv4 and IPv6, as the latter will be preferred

[alamb]

👀

[alamb]

Do you know how to get the resolved address? I tried addr.ip() but that still returns the unresolved port.

#[tokio::main]
async fn main() -> Result<(), DataFusionError> {
    let port = 9999;
    let addr: SocketAddr = format!("0.0.0.0:{port}").parse().unwrap();

    let listener = TcpListener::bind(addr).unwrap();
    let addr = listener.local_addr().unwrap();
    println!("Listening on: {}", addr);
    println!("Resolved host: {}", addr.ip().to_string());
    println!("Resolved port: {}", addr.port());

    Ok(())
}

Which prints out

Listening on: 0.0.0.0:9999
Resolved host: 0.0.0.0
Resolved port: 9999

I think only the actual Server knows the port after calling listen, but the tower/tonic thing only returns some sort of future (not a server that can be interrogated) 🤔

    let server = Server::builder().add_service(svc).serve(addr);

[tustvold]

IIRC you bind the TCPListener - https://docs.rs/tokio/1.40.0/tokio/net/struct.TcpListener.html, and get the address of it https://docs.rs/tokio/1.40.0/tokio/net/struct.TcpListener.html#method.local_addr

You can then construct a https://docs.rs/tonic/latest/tonic/transport/server/struct.TcpIncoming.html and feed this to the tonic builder.

It's a bit convoluted, but it is possible

[alamb]

I think my simple example from above does something like this (without the TcpIncoming) (binds to 0.0.0.0 and then gets local_addr) but that still seems to return 0.0.0.0

    let addr: SocketAddr = format!("0.0.0.0:{port}").parse().unwrap();

    let listener = TcpListener::bind(addr).unwrap();
    let addr = listener.local_addr().unwrap();

It seems like this is what listen_on also tries to do 🤔

arrow-rs/arrow-integration-testing/src/flight_server_scenarios/mod.rs

Lines 33 to 38 in 7781bc2

	let addr: SocketAddr = format!("0.0.0.0:{port}").parse()?;
	let listener = TcpListener::bind(addr).await?;
	let addr = listener.local_addr()?;
	Ok(addr)

[alamb]

It looks like other places in the tests also use localhost as the hostname here as well:

arrow-rs/arrow-integration-testing/src/flight_server_scenarios/middleware.rs

Line 103 in 7781bc2

let endpoint = super::endpoint("foo", "grpc+tcp://localhost:10010");

So maybe this is a problem that we can address if someone has issues running the tests on their environment. It "works for me" locally and it works on CI so perhaps that is good enough

I'll wait a while longer to see if anyone else has any good ideas

[alamb]

Let's go with this solution and revisit if anyone else has issues. As this is all a test harness I don't think this has any implications for actual Flight implementations