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POHow to reliably unlink() a Unix domain socket in Go programming language
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copied!<p>I have a Go program hosting a simple HTTP service on <code>localhost:8080</code> so I can connect my public <code>nginx</code> host to it via the <code>proxy_pass</code> directive, as a reverse proxy to serve part of my site's requests. This is all working great, no problems there.</p> <p>I want to convert the Go program to host the HTTP service on a Unix domain socket instead of a local TCP socket for improved security and to reduce the unnecessary protocol overhead of TCP.</p> <p><strong>PROBLEM</strong>: The problem is that Unix domain sockets cannot be reused once they are <code>bind()</code> to, even after program termination. The second time (and every time after) I run the Go program it exits with a fatal error <code>"address already in use"</code>.</p> <p>Common practice is to <code>unlink()</code> Unix domain sockets (i.e. remove the file) when the server shuts down. However, this is tricky in Go. My first attempt was to use the <code>defer</code> statement in my main func (see below), but it is not getting run if I interrupt the process with a signal like CTRL-C. I suppose this is to be expected. Disappointing, but not unexpected.</p> <p><strong>QUESTION</strong>: Is there a best practice on how to <code>unlink()</code> the socket when the server process shuts down (either gracefully or ungracefully)?</p> <p>Here's part of my <code>func main()</code> that starts the server listening for reference:</p> <pre><code>// Create the HTTP server listening on the requested socket: l, err := net.Listen("unix", "/tmp/mysocket") if err != nil { log.Fatal(err) } else { // Unix sockets must be unlink()ed before being reused again. // Unfortunately, this defer is not run when a signal is received, e.g. CTRL-C. defer func() { os.Remove("/tmp/mysocket") }() log.Fatal(http.Serve(l, http.HandlerFunc(indexHtml))) } </code></pre>

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