peridot/vendor/google.golang.org/api/transport/http/dial.go
2022-07-07 22:13:21 +02:00

305 lines
9.5 KiB
Go

// Copyright 2015 Google LLC.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package http supports network connections to HTTP servers.
// This package is not intended for use by end developers. Use the
// google.golang.org/api/option package to configure API clients.
package http
import (
"context"
"crypto/tls"
"errors"
"net"
"net/http"
"net/url"
"os"
"strings"
"time"
"go.opencensus.io/plugin/ochttp"
"golang.org/x/oauth2"
"google.golang.org/api/googleapi/transport"
"google.golang.org/api/internal"
"google.golang.org/api/option"
"google.golang.org/api/transport/cert"
"google.golang.org/api/transport/http/internal/propagation"
)
const (
mTLSModeAlways = "always"
mTLSModeNever = "never"
mTLSModeAuto = "auto"
)
// NewClient returns an HTTP client for use communicating with a Google cloud
// service, configured with the given ClientOptions. It also returns the endpoint
// for the service as specified in the options.
func NewClient(ctx context.Context, opts ...option.ClientOption) (*http.Client, string, error) {
settings, err := newSettings(opts)
if err != nil {
return nil, "", err
}
clientCertSource, err := getClientCertificateSource(settings)
if err != nil {
return nil, "", err
}
endpoint, err := getEndpoint(settings, clientCertSource)
if err != nil {
return nil, "", err
}
// TODO(cbro): consider injecting the User-Agent even if an explicit HTTP client is provided?
if settings.HTTPClient != nil {
return settings.HTTPClient, endpoint, nil
}
trans, err := newTransport(ctx, defaultBaseTransport(ctx, clientCertSource), settings)
if err != nil {
return nil, "", err
}
return &http.Client{Transport: trans}, endpoint, nil
}
// NewTransport creates an http.RoundTripper for use communicating with a Google
// cloud service, configured with the given ClientOptions. Its RoundTrip method delegates to base.
func NewTransport(ctx context.Context, base http.RoundTripper, opts ...option.ClientOption) (http.RoundTripper, error) {
settings, err := newSettings(opts)
if err != nil {
return nil, err
}
if settings.HTTPClient != nil {
return nil, errors.New("transport/http: WithHTTPClient passed to NewTransport")
}
return newTransport(ctx, base, settings)
}
func newTransport(ctx context.Context, base http.RoundTripper, settings *internal.DialSettings) (http.RoundTripper, error) {
paramTransport := &parameterTransport{
base: base,
userAgent: settings.UserAgent,
quotaProject: settings.QuotaProject,
requestReason: settings.RequestReason,
}
var trans http.RoundTripper = paramTransport
trans = addOCTransport(trans, settings)
switch {
case settings.NoAuth:
// Do nothing.
case settings.APIKey != "":
trans = &transport.APIKey{
Transport: trans,
Key: settings.APIKey,
}
default:
creds, err := internal.Creds(ctx, settings)
if err != nil {
return nil, err
}
if paramTransport.quotaProject == "" {
paramTransport.quotaProject = internal.QuotaProjectFromCreds(creds)
}
ts := creds.TokenSource
if settings.TokenSource != nil {
ts = settings.TokenSource
}
trans = &oauth2.Transport{
Base: trans,
Source: ts,
}
}
return trans, nil
}
func newSettings(opts []option.ClientOption) (*internal.DialSettings, error) {
var o internal.DialSettings
for _, opt := range opts {
opt.Apply(&o)
}
if err := o.Validate(); err != nil {
return nil, err
}
if o.GRPCConn != nil {
return nil, errors.New("unsupported gRPC connection specified")
}
return &o, nil
}
type parameterTransport struct {
userAgent string
quotaProject string
requestReason string
base http.RoundTripper
}
func (t *parameterTransport) RoundTrip(req *http.Request) (*http.Response, error) {
rt := t.base
if rt == nil {
return nil, errors.New("transport: no Transport specified")
}
newReq := *req
newReq.Header = make(http.Header)
for k, vv := range req.Header {
newReq.Header[k] = vv
}
if t.userAgent != "" {
// TODO(cbro): append to existing User-Agent header?
newReq.Header.Set("User-Agent", t.userAgent)
}
// Attach system parameters into the header
if t.quotaProject != "" {
newReq.Header.Set("X-Goog-User-Project", t.quotaProject)
}
if t.requestReason != "" {
newReq.Header.Set("X-Goog-Request-Reason", t.requestReason)
}
return rt.RoundTrip(&newReq)
}
// Set at init time by dial_appengine.go. If nil, we're not on App Engine.
var appengineUrlfetchHook func(context.Context) http.RoundTripper
// defaultBaseTransport returns the base HTTP transport.
// On App Engine, this is urlfetch.Transport.
// Otherwise, use a default transport, taking most defaults from
// http.DefaultTransport.
// If TLSCertificate is available, set TLSClientConfig as well.
func defaultBaseTransport(ctx context.Context, clientCertSource cert.Source) http.RoundTripper {
if appengineUrlfetchHook != nil {
return appengineUrlfetchHook(ctx)
}
// Copy http.DefaultTransport except for MaxIdleConnsPerHost setting,
// which is increased due to reported performance issues under load in the GCS
// client. Transport.Clone is only available in Go 1.13 and up.
trans := clonedTransport(http.DefaultTransport)
if trans == nil {
trans = fallbackBaseTransport()
}
trans.MaxIdleConnsPerHost = 100
if clientCertSource != nil {
trans.TLSClientConfig = &tls.Config{
GetClientCertificate: clientCertSource,
}
}
return trans
}
// fallbackBaseTransport is used in <go1.13 as well as in the rare case if
// http.DefaultTransport has been reassigned something that's not a
// *http.Transport.
func fallbackBaseTransport() *http.Transport {
return &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
DualStack: true,
}).DialContext,
MaxIdleConns: 100,
MaxIdleConnsPerHost: 100,
IdleConnTimeout: 90 * time.Second,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
}
}
func addOCTransport(trans http.RoundTripper, settings *internal.DialSettings) http.RoundTripper {
if settings.TelemetryDisabled {
return trans
}
return &ochttp.Transport{
Base: trans,
Propagation: &propagation.HTTPFormat{},
}
}
// getClientCertificateSource returns a default client certificate source, if
// not provided by the user.
//
// A nil default source can be returned if the source does not exist. Any exceptions
// encountered while initializing the default source will be reported as client
// error (ex. corrupt metadata file).
//
// The overall logic is as follows:
// 1. If both endpoint override and client certificate are specified, use them as is.
// 2. If user does not specify client certificate, we will attempt to use default
// client certificate.
// 3. If user does not specify endpoint override, we will use defaultMtlsEndpoint if
// client certificate is available and defaultEndpoint otherwise.
//
// Implications of the above logic:
// 1. If the user specifies a non-mTLS endpoint override but client certificate is
// available, we will pass along the cert anyway and let the server decide what to do.
// 2. If the user specifies an mTLS endpoint override but client certificate is not
// available, we will not fail-fast, but let backend throw error when connecting.
//
// We would like to avoid introducing client-side logic that parses whether the
// endpoint override is an mTLS url, since the url pattern may change at anytime.
func getClientCertificateSource(settings *internal.DialSettings) (cert.Source, error) {
if settings.HTTPClient != nil {
return nil, nil // HTTPClient is incompatible with ClientCertificateSource
} else if settings.ClientCertSource != nil {
return settings.ClientCertSource, nil
} else {
return cert.DefaultSource()
}
}
// getEndpoint returns the endpoint for the service, taking into account the
// user-provided endpoint override "settings.Endpoint"
//
// If no endpoint override is specified, we will either return the default endpoint or
// the default mTLS endpoint if a client certificate is available.
//
// You can override the default endpoint (mtls vs. regular) by setting the
// GOOGLE_API_USE_MTLS environment variable.
//
// If the endpoint override is an address (host:port) rather than full base
// URL (ex. https://...), then the user-provided address will be merged into
// the default endpoint. For example, WithEndpoint("myhost:8000") and
// WithDefaultEndpoint("https://foo.com/bar/baz") will return "https://myhost:8080/bar/baz"
func getEndpoint(settings *internal.DialSettings, clientCertSource cert.Source) (string, error) {
if settings.Endpoint == "" {
mtlsMode := getMTLSMode()
if mtlsMode == mTLSModeAlways || (clientCertSource != nil && mtlsMode == mTLSModeAuto) {
return settings.DefaultMTLSEndpoint, nil
}
return settings.DefaultEndpoint, nil
}
if strings.Contains(settings.Endpoint, "://") {
// User passed in a full URL path, use it verbatim.
return settings.Endpoint, nil
}
if settings.DefaultEndpoint == "" {
return "", errors.New("WithEndpoint requires a full URL path")
}
// Assume user-provided endpoint is host[:port], merge it with the default endpoint.
return mergeEndpoints(settings.DefaultEndpoint, settings.Endpoint)
}
func getMTLSMode() string {
mode := os.Getenv("GOOGLE_API_USE_MTLS")
if mode == "" {
// TODO(shinfan): Update this to "auto" when the mTLS feature is fully released.
return mTLSModeNever
}
return strings.ToLower(mode)
}
func mergeEndpoints(base, newHost string) (string, error) {
u, err := url.Parse(base)
if err != nil {
return "", err
}
u.Host = newHost
return u.String(), nil
}