vendor: update all dependencies

vendor/cloud.google.com/go/httpreplay/httpreplay.go

@@ -0,0 +1,148 @@
+// Copyright 2018 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.
+
+// +build go1.8
+
+// Package httpreplay provides an API for recording and replaying traffic
+// from HTTP-based Google API clients.
+//
+// To record:
+// 1.  Call NewRecorder to get a Recorder.
+// 2.  Use its Client method to obtain an HTTP client to use when making API calls.
+// 3.  Close the Recorder when you're done. That will save the
+//     log of interactions to the file you provided to NewRecorder.
+//
+// To replay:
+// 1.  Call NewReplayer with the same filename you used to record to get a Replayer.
+// 2.  Call its Client method and use the client to make the same API calls.
+//     You will get back the recorded responses.
+// 3.  Close the Replayer when you're done.
+//
+// This package is EXPERIMENTAL and is subject to change or removal without notice.
+// It requires Go version 1.8 or higher.
+package httpreplay
+
+// TODO(jba): add examples.
+
+import (
+	"fmt"
+	"net/http"
+
+	"cloud.google.com/go/httpreplay/internal/proxy"
+	"golang.org/x/net/context"
+	"golang.org/x/oauth2"
+	"google.golang.org/api/option"
+	htransport "google.golang.org/api/transport/http"
+)
+
+// A Recorder records HTTP interactions.
+type Recorder struct {
+	filename string
+	proxy    *proxy.Proxy
+}
+
+// NewRecorder creates a recorder that writes to filename. The file will
+// also store initial state that can be retrieved to configure replay. The "initial"
+// argument must work with json.Marshal.
+//
+// You must call Close on the Recorder to ensure that all data is written.
+func NewRecorder(filename string, initial interface{}) (*Recorder, error) {
+	p, err := proxy.ForRecording(filename, 0)
+	if err != nil {
+		return nil, err
+	}
+	p.Initial = initial
+	return &Recorder{proxy: p}, nil
+}
+
+// Client returns an http.Client to be used for recording. Provide authentication options
+// like option.WithTokenSource as you normally would, or omit them to use Application Default
+// Credentials.
+func (r *Recorder) Client(ctx context.Context, opts ...option.ClientOption) (*http.Client, error) {
+	hc, _, err := htransport.NewClient(ctx, opts...)
+	if err != nil {
+		return nil, err
+	}
+	// The http.Client returned by htransport.NewClient contains an
+	// http.RoundTripper. We want to somehow plug in a Transport that calls the proxy
+	// (returned by r.proxy.Transport).
+	//
+	// htransport.NewClient constructs its RoundTripper via the decorator pattern, by
+	// nesting several implementations of RoundTripper inside each other, ending with
+	// http.DefaultTransport. For example, one of the decorators is oauth2.Transport,
+	// which inserts an Authorization header and then calls the next RoundTripper in
+	// the sequence (stored in a field called Base).
+	//
+	// The problem is that we need to insert the proxy Transport at the end of this
+	// sequence, where http.DefaultTransport currently lives. But we can't traverse
+	// that sequence of RoundTrippers in general, because we don't know their types.
+	//
+	// For now, we only handle the special (but common) case where the first
+	// RoundTripper in the sequence is an oauth2.Transport. We can replace its Base
+	// field with the proxy transport. This causes us to lose the other RoundTrippers
+	// in the sequence, but those aren't essential for testing.
+	//
+	// A better solution would be to add option.WithBaseTransport, which would allow
+	// us to replace the http.DefaultTransport at the end of the sequence with the
+	// transport of our choice.
+	otrans, ok := hc.Transport.(*oauth2.Transport)
+	if !ok {
+		return nil, fmt.Errorf("can't handle Transport of type %T", hc.Transport)
+	}
+	otrans.Base = r.proxy.Transport()
+	return hc, nil
+}
+
+// Close closes the Recorder and saves the log file.
+func (r *Recorder) Close() error {
+	return r.proxy.Close()
+}
+
+// A Replayer replays previously recorded HTTP interactions.
+type Replayer struct {
+	proxy *proxy.Proxy
+}
+
+// NewReplayer creates a replayer that reads from filename.
+func NewReplayer(filename string) (*Replayer, error) {
+	p, err := proxy.ForReplaying(filename, 0)
+	if err != nil {
+		return nil, err
+	}
+	return &Replayer{proxy: p}, nil
+}
+
+// Client returns an HTTP client for replaying. The client does not need to be
+// configured with credentials for authenticating to a server, since it never
+// contacts a real backend.
+func (r *Replayer) Client(ctx context.Context) (*http.Client, error) {
+	return &http.Client{Transport: r.proxy.Transport()}, nil
+}
+
+// Initial returns the initial state saved by the Recorder.
+func (r *Replayer) Initial() interface{} {
+	return r.proxy.Initial
+}
+
+// Close closes the replayer.
+func (r *Replayer) Close() error {
+	return r.proxy.Close()
+}
+
+// DebugHeaders helps to determine whether a header should be ignored.
+// When true, if requests have the same method, URL and body but differ
+// in a header, the first mismatched header is logged.
+func DebugHeaders() {
+	proxy.DebugHeaders = true
+}