Kevin Postal Kevin Postal - 5 months ago 44
Linux Question

Golang Keeps File Serve Socket Open After Close

I created a file server in golang and call the Close() method on the Listener.

When I try to access the Port on a new Web connection it appears the Socket is closed and I am unable to access the website.

How ever if I referesh the page with a connection that has already been established.... the page reloads fine as if the socket was never closed? I am even able to still browse around the file system.

I noticed after 30 or so minutes the socket seems to force close.

Is there something I am missing to force the socket to drop all existing connections to prevent people from accessing the file server?

var fileListener net.Listener
host_string = "127.0.0.1:8080"
fileListener, _ = net.Listen("tcp", host_string)
server := &http.Server{Addr: host_string, Handler:
http.FileServer(http.Dir("/"))}
go func() { server.Serve(fileListener) }()
fileListener.Close()

Answer

There's no way to shut down idle HTTP/1.1 or HTTP2 connections. There is a an open issue at https://golang.org/issue/9478, but no immediate plans for it. Note that once you close your listener, your server will not accept new connections; you're reusing the same connection.

If you want to forcefully close all connections, you would need to do the bookkeeping yourself using the http.Server ConnState to track the TCP connections that are active.

You could also have your handlers set Connection: close on each response, but that would make your http server much less efficient if clients ever need to make more than 1 request.