possible Improvement: Using shutdown() Before close() in `server.py`

[allrob23]

Description:

While reviewing the get_routable_ip_to function in torchx/apps/serve/serve.py, I noticed that the socket is directly closed using s.close(), without calling shutdown() beforehand.

def get_routable_ip_to(addr: str) -> str:
    """
    get_routable_ip_to opens a dummy connection to the target HTTP URL and
    returns the IP address used to connect to it.
    """
    parsed = urlparse(addr)
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect((parsed.hostname, parsed.port or 80))
        return s.getsockname()[0]
    finally:
        s.close()

Question

Would there be any potential downsides or benefits to adding a shutdown(socket.SHUT_RDWR) call before closing the socket in the get_routable_ip_to function?

Possible Benefits

• Ensures that all pending data is properly discarded before closing, particularly if the socket is still in a half-open state.
• Prevents potential issues with lingering resources and improves resource management.
• Aligns with best practices for socket cleanup.

Reference

The Python socket documentation states:

"close() releases the resource associated with a connection but does not necessarily close the connection immediately. If you want to close the connection in a timely fashion, call shutdown() before close()." link

Looking forward to your thoughts!

Thanks!