116 lines
3.5 KiB
Go
116 lines
3.5 KiB
Go
// 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"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"net/http"
|
|
"os"
|
|
"path/filepath"
|
|
"runtime"
|
|
|
|
"cloud.google.com/go/compute/metadata"
|
|
"golang.org/x/net/context"
|
|
"golang.org/x/oauth2"
|
|
)
|
|
|
|
// DefaultClient returns an HTTP Client that uses the
|
|
// DefaultTokenSource to obtain authentication 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 returns the token source for
|
|
// "Application Default Credentials".
|
|
// It is a shortcut for FindDefaultCredentials(ctx, scope).TokenSource.
|
|
func DefaultTokenSource(ctx context.Context, scope ...string) (oauth2.TokenSource, error) {
|
|
creds, err := FindDefaultCredentials(ctx, scope...)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return creds.TokenSource, nil
|
|
}
|
|
|
|
// Common implementation for FindDefaultCredentials.
|
|
func findDefaultCredentials(ctx context.Context, scopes []string) (*DefaultCredentials, error) {
|
|
// First, try the environment variable.
|
|
const envVar = "GOOGLE_APPLICATION_CREDENTIALS"
|
|
if filename := os.Getenv(envVar); filename != "" {
|
|
creds, err := readCredentialsFile(ctx, filename, scopes)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("google: error getting credentials using %v environment variable: %v", envVar, err)
|
|
}
|
|
return creds, nil
|
|
}
|
|
|
|
// Second, try a well-known file.
|
|
filename := wellKnownFile()
|
|
if creds, err := readCredentialsFile(ctx, filename, scopes); err == nil {
|
|
return creds, nil
|
|
} else if !os.IsNotExist(err) {
|
|
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 && !appengineFlex {
|
|
return &DefaultCredentials{
|
|
ProjectID: appengineAppIDFunc(ctx),
|
|
TokenSource: AppEngineTokenSource(ctx, scopes...),
|
|
}, nil
|
|
}
|
|
|
|
// Fourth, if we're on Google Compute Engine use the metadata server.
|
|
if metadata.OnGCE() {
|
|
id, _ := metadata.ProjectID()
|
|
return &DefaultCredentials{
|
|
ProjectID: id,
|
|
TokenSource: 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)
|
|
}
|
|
|
|
// Common implementation for CredentialsFromJSON.
|
|
func credentialsFromJSON(ctx context.Context, jsonData []byte, scopes []string) (*DefaultCredentials, error) {
|
|
var f credentialsFile
|
|
if err := json.Unmarshal(jsonData, &f); err != nil {
|
|
return nil, err
|
|
}
|
|
ts, err := f.tokenSource(ctx, append([]string(nil), scopes...))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &DefaultCredentials{
|
|
ProjectID: f.ProjectID,
|
|
TokenSource: ts,
|
|
JSON: jsonData,
|
|
}, nil
|
|
}
|
|
|
|
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 readCredentialsFile(ctx context.Context, filename string, scopes []string) (*DefaultCredentials, error) {
|
|
b, err := ioutil.ReadFile(filename)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return CredentialsFromJSON(ctx, b, scopes...)
|
|
}
|