/usr/share/gocode/src/golang.org/x/oauth2/google/default.go is in golang-golang-x-oauth2-google-dev 0.0~git20161103.0.36bc617-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 | // Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package google
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net/http"
"os"
"path/filepath"
"runtime"
"google.golang.org/cloud/compute/metadata"
"golang.org/x/net/context"
"golang.org/x/oauth2"
"golang.org/x/oauth2/jwt"
)
// DefaultClient returns an HTTP Client that uses the
// DefaultTokenSource to obtain authentication credentials.
//
// This client should be used when developing services
// that run on Google App Engine or Google Compute Engine
// and use "Application Default Credentials."
//
// For more details, see:
// https://developers.google.com/accounts/docs/application-default-credentials
//
func DefaultClient(ctx context.Context, scope ...string) (*http.Client, error) {
ts, err := DefaultTokenSource(ctx, scope...)
if err != nil {
return nil, err
}
return oauth2.NewClient(ctx, ts), nil
}
// DefaultTokenSource is a token source that uses
// "Application Default Credentials".
//
// It looks for credentials in the following places,
// preferring the first location found:
//
// 1. A JSON file whose path is specified by the
// GOOGLE_APPLICATION_CREDENTIALS environment variable.
// 2. A JSON file in a location known to the gcloud command-line tool.
// On Windows, this is %APPDATA%/gcloud/application_default_credentials.json.
// On other systems, $HOME/.config/gcloud/application_default_credentials.json.
// 3. On Google App Engine it uses the appengine.AccessToken function.
// 4. On Google Compute Engine and Google App Engine Managed VMs, it fetches
// credentials from the metadata server.
// (In this final case any provided scopes are ignored.)
//
// For more details, see:
// https://developers.google.com/accounts/docs/application-default-credentials
//
func DefaultTokenSource(ctx context.Context, scope ...string) (oauth2.TokenSource, error) {
// First, try the environment variable.
const envVar = "GOOGLE_APPLICATION_CREDENTIALS"
if filename := os.Getenv(envVar); filename != "" {
ts, err := tokenSourceFromFile(ctx, filename, scope)
if err != nil {
return nil, fmt.Errorf("google: error getting credentials using %v environment variable: %v", envVar, err)
}
return ts, nil
}
// Second, try a well-known file.
filename := wellKnownFile()
_, err := os.Stat(filename)
if err == nil {
ts, err2 := tokenSourceFromFile(ctx, filename, scope)
if err2 == nil {
return ts, nil
}
err = err2
} else if os.IsNotExist(err) {
err = nil // ignore this error
}
if err != nil {
return nil, fmt.Errorf("google: error getting credentials using well-known file (%v): %v", filename, err)
}
// Third, if we're on Google App Engine use those credentials.
if appengineTokenFunc != nil && !appengineVM {
return AppEngineTokenSource(ctx, scope...), nil
}
// Fourth, if we're on Google Compute Engine use the metadata server.
if metadata.OnGCE() {
return ComputeTokenSource(""), nil
}
// None are found; return helpful error.
const url = "https://developers.google.com/accounts/docs/application-default-credentials"
return nil, fmt.Errorf("google: could not find default credentials. See %v for more information.", url)
}
func wellKnownFile() string {
const f = "application_default_credentials.json"
if runtime.GOOS == "windows" {
return filepath.Join(os.Getenv("APPDATA"), "gcloud", f)
}
return filepath.Join(guessUnixHomeDir(), ".config", "gcloud", f)
}
func tokenSourceFromFile(ctx context.Context, filename string, scopes []string) (oauth2.TokenSource, error) {
b, err := ioutil.ReadFile(filename)
if err != nil {
return nil, err
}
var d struct {
// Common fields
Type string
ClientID string `json:"client_id"`
// User Credential fields
ClientSecret string `json:"client_secret"`
RefreshToken string `json:"refresh_token"`
// Service Account fields
ClientEmail string `json:"client_email"`
PrivateKeyID string `json:"private_key_id"`
PrivateKey string `json:"private_key"`
}
if err := json.Unmarshal(b, &d); err != nil {
return nil, err
}
switch d.Type {
case "authorized_user":
cfg := &oauth2.Config{
ClientID: d.ClientID,
ClientSecret: d.ClientSecret,
Scopes: append([]string{}, scopes...), // copy
Endpoint: Endpoint,
}
tok := &oauth2.Token{RefreshToken: d.RefreshToken}
return cfg.TokenSource(ctx, tok), nil
case "service_account":
cfg := &jwt.Config{
Email: d.ClientEmail,
PrivateKey: []byte(d.PrivateKey),
Scopes: append([]string{}, scopes...), // copy
TokenURL: JWTTokenURL,
}
return cfg.TokenSource(ctx), nil
case "":
return nil, errors.New("missing 'type' field in credentials")
default:
return nil, fmt.Errorf("unknown credential type: %q", d.Type)
}
}
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