Merge pull request #3254 from lorenz/allow-http2

Allow HTTP/2

changelog/unreleased/pull-3254

@@ -0,0 +1,8 @@
+Enhancement: Enable HTTP/2 for backend connections
+
+Go's HTTP library usually automatically chooses between HTTP/1.x and HTTP/2
+depending on what the server supports. But for compatibility this mechanism
+is disabled if DialContext is used (which is the case for restic). This change
+allows restic's HTTP client to negotiate HTTP/2 if supported by the server.
+
+https://github.com/restic/restic/pull/3254

internal/backend/http_transport.go

@@ -70,6 +70,7 @@ func Transport(opts TransportOptions) (http.RoundTripper, error) {
 			KeepAlive: 30 * time.Second,
 			DualStack: true,
 		}).DialContext,
+		ForceAttemptHTTP2:     true,
 		MaxIdleConns:          100,
 		MaxIdleConnsPerHost:   100,
 		IdleConnTimeout:       90 * time.Second,