Patrick Jones 01de73cf58 google: base account credentials with file-sourcing
Implements the core functionality to allow 3rd party identities access to Google APIs.  Specifically, this PR implements the base account credential type and supports file-sourced credentials such as Kubernetes workloads.  Later updates will add support for URL-sourced credentials such as Microsoft Azure and support for AWS credentials.

Change-Id: I6e09a450f5221a1e06394b51374cff70ab3ab8a7
GitHub-Last-Rev: 3ab51622f8f7c6982a5e78ae9644675659318e7b
GitHub-Pull-Request: golang/oauth2#462
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/276312
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>
Trust: Tyler Bui-Palsulich <tbp@google.com>
Trust: Cody Oss <codyoss@google.com>
Run-TryBot: Tyler Bui-Palsulich <tbp@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-01-12 20:04:29 +00:00

58 lines
1.5 KiB
Go

// Copyright 2020 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 externalaccount
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
)
type fileCredentialSource struct {
File string
Format format
}
func (cs fileCredentialSource) subjectToken() (string, error) {
tokenFile, err := os.Open(cs.File)
if err != nil {
return "", fmt.Errorf("oauth2/google: failed to open credential file %q", cs.File)
}
defer tokenFile.Close()
tokenBytes, err := ioutil.ReadAll(io.LimitReader(tokenFile, 1<<20))
if err != nil {
return "", fmt.Errorf("oauth2/google: failed to read credential file: %v", err)
}
tokenBytes = bytes.TrimSpace(tokenBytes)
switch cs.Format.Type {
case "json":
jsonData := make(map[string]interface{})
err = json.Unmarshal(tokenBytes, &jsonData)
if err != nil {
return "", fmt.Errorf("oauth2/google: failed to unmarshal subject token file: %v", err)
}
val, ok := jsonData[cs.Format.SubjectTokenFieldName]
if !ok {
return "", errors.New("oauth2/google: provided subject_token_field_name not found in credentials")
}
token, ok := val.(string)
if !ok {
return "", errors.New("oauth2/google: improperly formatted subject token")
}
return token, nil
case "text":
return string(tokenBytes), nil
case "":
return string(tokenBytes), nil
default:
return "", errors.New("oauth2/google: invalid credential_source file format type")
}
}