105 lines
3.2 KiB
Go
105 lines
3.2 KiB
Go
// Copyright 2017 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package internal
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import (
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"encoding/json"
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"fmt"
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"io/ioutil"
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"time"
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"golang.org/x/net/context"
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"golang.org/x/oauth2"
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"golang.org/x/oauth2/google"
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)
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// Creds returns credential information obtained from DialSettings, or if none, then
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// it returns default credential information.
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func Creds(ctx context.Context, ds *DialSettings) (*google.DefaultCredentials, error) {
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if ds.CredentialsFile != "" {
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return credFileTokenSource(ctx, ds.CredentialsFile, ds.Scopes...)
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}
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if ds.TokenSource != nil {
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return &google.DefaultCredentials{TokenSource: ds.TokenSource}, nil
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}
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return google.FindDefaultCredentials(ctx, ds.Scopes...)
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}
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// credFileTokenSource reads a refresh token file or a service account and returns
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// a TokenSource constructed from the config.
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func credFileTokenSource(ctx context.Context, filename string, scope ...string) (*google.DefaultCredentials, error) {
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data, err := ioutil.ReadFile(filename)
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if err != nil {
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return nil, fmt.Errorf("cannot read credentials file: %v", err)
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}
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// See if it is a refresh token credentials file first.
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ts, ok, err := refreshTokenTokenSource(ctx, data, scope...)
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if err != nil {
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return nil, err
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}
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if ok {
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return &google.DefaultCredentials{
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TokenSource: ts,
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JSON: data,
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}, nil
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}
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// If not, it should be a service account.
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cfg, err := google.JWTConfigFromJSON(data, scope...)
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if err != nil {
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return nil, fmt.Errorf("google.JWTConfigFromJSON: %v", err)
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}
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// jwt.Config does not expose the project ID, so re-unmarshal to get it.
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var pid struct {
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ProjectID string `json:"project_id"`
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}
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if err := json.Unmarshal(data, &pid); err != nil {
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return nil, err
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}
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return &google.DefaultCredentials{
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ProjectID: pid.ProjectID,
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TokenSource: cfg.TokenSource(ctx),
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JSON: data,
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}, nil
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}
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func refreshTokenTokenSource(ctx context.Context, data []byte, scope ...string) (oauth2.TokenSource, bool, error) {
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var c cred
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if err := json.Unmarshal(data, &c); err != nil {
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return nil, false, fmt.Errorf("cannot unmarshal credentials file: %v", err)
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}
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if c.ClientID == "" || c.ClientSecret == "" || c.RefreshToken == "" || c.Type != "authorized_user" {
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return nil, false, nil
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}
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cfg := &oauth2.Config{
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ClientID: c.ClientID,
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ClientSecret: c.ClientSecret,
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Endpoint: google.Endpoint,
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RedirectURL: "urn:ietf:wg:oauth:2.0:oob",
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Scopes: scope,
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}
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return cfg.TokenSource(ctx, &oauth2.Token{
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RefreshToken: c.RefreshToken,
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Expiry: time.Now(),
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}), true, nil
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}
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type cred struct {
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ClientID string `json:"client_id"`
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ClientSecret string `json:"client_secret"`
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RefreshToken string `json:"refresh_token"`
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Type string `json:"type"`
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}
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