Fabio does not serve http2 with go >= 1.7

[smancke]

We found out, that fabio currently is not doing http2.
The reasons seems to be a change in go's behavior, when you supply a custom tls.Config (see golang/go#15908).
Before 1.7 it was fine to have NextProtos: nil, now it has to be set explicitly. NextProtos: []string{"h2"}.
The same thing hit the caddy server (see caddyserver/caddy#976).

When I add

	x := &tls.Config{
		NextProtos: []string{"h2"},

in cert/source.go it has http support. This seems to be consistent to the documentation of the method shouldConfigureHTTP2ForServe() in net/http/server.

[magiconair]

@smancke like this?

[smancke]

@magiconair yes

[magiconair]

I'm trying to see an HTTP/2 request in the testSource() function in cert/source_test.go but I don't see it. Trying to print the proto and somehow expecting HTTP/2 here:

srv := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	fmt.Println("Proto:", r.Proto)
	fmt.Fprint(w, "OK")
}))

Any idea what I'm missing?

[smancke]

the go http client does not do http2 by default, if you configure it with a custom tls config:

in net/http/transport.go

func (t *Transport) onceSetNextProtoDefaults() {
...
	if t.TLSClientConfig != nil || t.Dial != nil || t.DialTLS != nil {
		// Be conservative and don't automatically enable
		// http2 if they've specified a custom TLS config or
		// custom dialers. Let them opt-in themselves via
		// http2.ConfigureTransport so we don't surprise them
		// by modifying their tls.Config. Issue 14275.
		return
	}
...
}

There must be a way to force the transport by hand, but I don't found how ..

[smancke]

@magiconair
This works for configuring the client, using the golang/x http2 package:

      import "golang.org/x/net/http2"

	clientTransport := &http.Transport{
		TLSClientConfig: &tls.Config{
			RootCAs: rootCAs,
		},
	}
	http2.ConfigureTransport(clientTransport)
	client := http.Client{
		Transport: clientTransport,
	}

Proto: HTTP/2.0

[magiconair]

@smancke Awesome. Thanks a lot. I've updated the change to include the test. Testing for HTTP/2 feels grafted on though. Maybe its better to move this to a separate test but for now at least there is a test.

[smancke]

Cool!!
Any idea, when this will be in a release?

[magiconair]

@smancke I can spin a 1.3.6 tomorrow. Also, time to wrap up the other lingering changes. Quick enough?

[smancke]

Yes, would be very great!
Thanks a lot!!

[magiconair]

Thanks for finding and helping! Appreciated.

[magiconair]

Merged to master and published in 1.3.6 release.