How to close a server?

[danieljfarrell]

I want to start and stop a thriftpy2 service from inside a running desktop application. However, calling close on the server does not terminate it’s thread and the application hangs.

For example,

def start_button_clicked(self):
    self.server = make_server(...)
    self.thd = threading.Thread(target=server.serve)

def stop_button_clicked(self):
    self.server.close()
    self.thd.join() # <— hangs 
    self.server = None
    self.thd = None

Maybe I am doing something wrong?

I’m using Python 3.6.9 and thriftpy2 0.4.10 on Windows 10.

[danieljfarrell]

thriftpy2/thriftpy2/transport/socket.py

Line 219 in b78720e

client, _ = self.sock.accept()

It seems the thread is blocking here, waiting for the socket to accept something.

[danieljfarrell]

I came across this similar issue on the deprecated project page, Thriftpy/thriftpy#295. If I kill the transport and the socket I can get the threat to terminate, however, it does so by raising an exception.

def stop_button_clicked(self):
    server.close()
    server.trans.close()  # <-- kill this
    server.trans.sock.close()  # <-- kill this, Exception is raised
    self.thd.join()  #  need to wrap in try-except to finish tear down 
    self.server = None
    self.thd = None

What would you like to do? Shall I prepare a pull request?

[ethe]

Hanging in accept means there is still at least one socket that is connection completed and waiting for transporting from the client, close it right now would make the client raise an exception.

[aisk]

Another way to solve this is you can set a timeout on server socket like this: server.trans.sock.settimeout(1). And the accept should in a dead loop to call this eventually, and with a flag to check should it closed.

[danieljfarrell]

Thanks for the comments both! So there must be a client connection still open, otherwise the server should close?

Setting the timeout on the socket is a much better way to go.