TUN-3896: http-service and tunnelstore client use http2 transport.

- If origin services are http2 and https is the service url, http2
   transport is preferred.

   - The tunnelstore client is now upgraded to use http2.

CHANGES.md

@@ -1,5 +1,24 @@
 **Experimental**: This is a new format for release notes. The format and availability is subject to change.
 
+## UNRELEASED
+
+### Backward Incompatible Changes
+
+- none
+
+### New Features
+
+ - HTTP/2 transport is now always chosen if origin server supports it and the service url scheme is HTTPS.
+   This was previously done in a best attempt manner.
+
+### Improvements
+
+- none
+
+### Bug Fixes
+
+ - none
+
 ## 2021.3.3
 
 ### Improvements

ingress/origin_service.go

@@ -15,6 +15,8 @@ import (
 	"github.com/pkg/errors"
 	"github.com/rs/zerolog"
 
+	"golang.org/x/net/http2"
+
 	"github.com/cloudflare/cloudflared/hello"
 	"github.com/cloudflare/cloudflared/ipaccess"
 	"github.com/cloudflare/cloudflared/socks"
@@ -287,6 +289,7 @@ func newHTTPTransport(service originService, cfg OriginRequestConfig, log *zerol
 		httpTransport.DialContext = dialContext
 	}
 
+	http2.ConfigureTransport(&httpTransport)
 	return &httpTransport, nil
 }
 

tunnelstore/client.go

@@ -16,6 +16,8 @@ import (
 	"github.com/pkg/errors"
 	"github.com/rs/zerolog"
 
+	"golang.org/x/net/http2"
+
 	"github.com/cloudflare/cloudflared/teamnet"
 )
 
@@ -247,6 +249,11 @@ func NewRESTClient(baseURL, accountTag, zoneTag, authToken, userAgent string, lo
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to create account level endpoint")
 	}
+	httpTransport := http.Transport{
+		TLSHandshakeTimeout:   defaultTimeout,
+		ResponseHeaderTimeout: defaultTimeout,
+	}
+	http2.ConfigureTransport(&httpTransport)
 	return &RESTClient{
 		baseEndpoints: &baseEndpoints{
 			accountLevel:  *accountLevelEndpoint,
@@ -256,10 +263,7 @@ func NewRESTClient(baseURL, accountTag, zoneTag, authToken, userAgent string, lo
 		authToken: authToken,
 		userAgent: userAgent,
 		client: http.Client{
-			Transport: &http.Transport{
+			Transport: &httpTransport,
-				TLSHandshakeTimeout:   defaultTimeout,
-				ResponseHeaderTimeout: defaultTimeout,
-			},
 			Timeout:   defaultTimeout,
 		},
 		log: log,