Autocert failure with HTTP handler

[cpu...@gmail.com]

Hello, 

I have a very stupid problem with autocert. The below code works:

log.Println("sslHosts:", sslHosts)

log.Println("sslCertDir:", sslCertDir)

certManager := autocert.Manager{

Prompt: autocert.AcceptTOS,

HostPolicy: autocert.HostWhitelist(strings.Split(sslHosts, " ")...),

Cache: autocert.DirCache(sslCertDir),

}

go func() {

log.Fatal(http.ListenAndServe(":http", certManager.HTTPHandler(nil)))

}()

// go log.Fatal(http.ListenAndServe(":http", certManager.HTTPHandler(nil)))

s.Addr = ":https"

s.TLSConfig = certManager.TLSConfig()

log.Fatal(s.ListenAndServeTLS("", ""))

Once I remove the go func() and uncomment the // go log line, the server no longer serves HTTPS requests while HTTP continues to work. 

I'm totally stumped- the two go funcs should imho be equivalent? Any insight what's wrong here would be highly appreciated. 

I'm using go 1.16.3-arm64 on Darwin, cross-compiled to amd64.

Cheers,

Andi

[Brian Candler]

As far as I understand it: "go foo(bar, baz)" evaluates all the arguments first, *then* starts a goroutine with function foo(val1, val2)

Since http.ListenAndServe() never returns [unless it fails to start], it never gets as far as starting a goroutine for log.Fatal, and therefore cannot continue to the rest of the code.

[cpu...@gmail.com]

That makes perfect sense as the simple reproducer shows: https://play.golang.org/p/vSEBtdV2CzR

Only in this case I didn't see it as there were more go routines alive.

Much appreciated, thank you!

[Brian Candler]

Another way to look at it:

https://play.golang.org/p/8c3EgpiXS8e