transport.go

// Copyright 2020 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
	"crypto/tls"
	"fmt"
	"net/http"
)

const (
	http1 = "HTTP/1.1"
	http2 = "HTTP/2"
)

func getTransport(
	transportType string,
	maxConnsPerHost int) (transport *http.Transport) {
	switch transportType {
	case http1:
		return getTransportHTTP1(maxConnsPerHost)
	case http2:
		return http.DefaultTransport.(*http.Transport).Clone()
	default:
		panic(fmt.Errorf("Unknown tranport type: %q", transportType))
	}
}

func getTransportHTTP1(maxConnsPerHost int) (transport *http.Transport) {
	return &http.Transport{
		MaxConnsPerHost: maxConnsPerHost,
		// This disables HTTP/2 in the transport.
		TLSNextProto: make(
			map[string]func(string, *tls.Conn) http.RoundTripper,
		),
	}
}