http2: add ConfigureTransports

The ConfigureTransport function doesn't provide any way to get at the
http2 Transport it creates, making it impossible to configure transport
parameters such as ReadIdleTimeout.

Add a ConfigureTransports function which returns the http2 Transport.

The very similar names are unfortunate, but they'll sort next to each
other in godoc and the pluralized ConfigureTransports hints at its purpose:
it lets you configure both the http and http2 transports.

Fixes golang/go#40201.
Updates golang/go#41721.

Change-Id: I97aa345f369f49462c41d3f60d35660c06c51287
Reviewed-on: https://go-review.googlesource.com/c/net/+/264017
Trust: Damien Neil <[email protected]>
Trust: Brad Fitzpatrick <[email protected]>
Run-TryBot: Damien Neil <[email protected]>
Reviewed-by: Brad Fitzpatrick <[email protected]>

Author: neild

http2/transport.go

@@ -154,12 +154,21 @@ func (t *Transport) pingTimeout() time.Duration {
 
 // ConfigureTransport configures a net/http HTTP/1 Transport to use HTTP/2.
 // It returns an error if t1 has already been HTTP/2-enabled.
+//
+// Use ConfigureTransports instead to configure the HTTP/2 Transport.
 func ConfigureTransport(t1 *http.Transport) error {
-	_, err := configureTransport(t1)
+	_, err := ConfigureTransports(t1)
 	return err
 }
 
-func configureTransport(t1 *http.Transport) (*Transport, error) {
+// ConfigureTransports configures a net/http HTTP/1 Transport to use HTTP/2.
+// It returns a new HTTP/2 Transport for further configuration.
+// It returns an error if t1 has already been HTTP/2-enabled.
+func ConfigureTransports(t1 *http.Transport) (*Transport, error) {
+	return configureTransports(t1)
+}
+
+func configureTransports(t1 *http.Transport) (*Transport, error) {
 	connPool := new(clientConnPool)
 	t2 := &Transport{
 		ConnPool: noDialClientConnPool{connPool},