(feat) Add auto-discovery in k8s | Adarsh

vendor/golang.org/x/oauth2/google/sdk.go

@@ -0,0 +1,201 @@
+// 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 (
+	"bufio"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/user"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+type sdkCredentials struct {
+	Data []struct {
+		Credential struct {
+			ClientID     string     `json:"client_id"`
+			ClientSecret string     `json:"client_secret"`
+			AccessToken  string     `json:"access_token"`
+			RefreshToken string     `json:"refresh_token"`
+			TokenExpiry  *time.Time `json:"token_expiry"`
+		} `json:"credential"`
+		Key struct {
+			Account string `json:"account"`
+			Scope   string `json:"scope"`
+		} `json:"key"`
+	}
+}
+
+// An SDKConfig provides access to tokens from an account already
+// authorized via the Google Cloud SDK.
+type SDKConfig struct {
+	conf         oauth2.Config
+	initialToken *oauth2.Token
+}
+
+// NewSDKConfig creates an SDKConfig for the given Google Cloud SDK
+// account. If account is empty, the account currently active in
+// Google Cloud SDK properties is used.
+// Google Cloud SDK credentials must be created by running `gcloud auth`
+// before using this function.
+// The Google Cloud SDK is available at https://cloud.google.com/sdk/.
+func NewSDKConfig(account string) (*SDKConfig, error) {
+	configPath, err := sdkConfigPath()
+	if err != nil {
+		return nil, fmt.Errorf("oauth2/google: error getting SDK config path: %v", err)
+	}
+	credentialsPath := filepath.Join(configPath, "credentials")
+	f, err := os.Open(credentialsPath)
+	if err != nil {
+		return nil, fmt.Errorf("oauth2/google: failed to load SDK credentials: %v", err)
+	}
+	defer f.Close()
+
+	var c sdkCredentials
+	if err := json.NewDecoder(f).Decode(&c); err != nil {
+		return nil, fmt.Errorf("oauth2/google: failed to decode SDK credentials from %q: %v", credentialsPath, err)
+	}
+	if len(c.Data) == 0 {
+		return nil, fmt.Errorf("oauth2/google: no credentials found in %q, run `gcloud auth login` to create one", credentialsPath)
+	}
+	if account == "" {
+		propertiesPath := filepath.Join(configPath, "properties")
+		f, err := os.Open(propertiesPath)
+		if err != nil {
+			return nil, fmt.Errorf("oauth2/google: failed to load SDK properties: %v", err)
+		}
+		defer f.Close()
+		ini, err := parseINI(f)
+		if err != nil {
+			return nil, fmt.Errorf("oauth2/google: failed to parse SDK properties %q: %v", propertiesPath, err)
+		}
+		core, ok := ini["core"]
+		if !ok {
+			return nil, fmt.Errorf("oauth2/google: failed to find [core] section in %v", ini)
+		}
+		active, ok := core["account"]
+		if !ok {
+			return nil, fmt.Errorf("oauth2/google: failed to find %q attribute in %v", "account", core)
+		}
+		account = active
+	}
+
+	for _, d := range c.Data {
+		if account == "" || d.Key.Account == account {
+			if d.Credential.AccessToken == "" && d.Credential.RefreshToken == "" {
+				return nil, fmt.Errorf("oauth2/google: no token available for account %q", account)
+			}
+			var expiry time.Time
+			if d.Credential.TokenExpiry != nil {
+				expiry = *d.Credential.TokenExpiry
+			}
+			return &SDKConfig{
+				conf: oauth2.Config{
+					ClientID:     d.Credential.ClientID,
+					ClientSecret: d.Credential.ClientSecret,
+					Scopes:       strings.Split(d.Key.Scope, " "),
+					Endpoint:     Endpoint,
+					RedirectURL:  "oob",
+				},
+				initialToken: &oauth2.Token{
+					AccessToken:  d.Credential.AccessToken,
+					RefreshToken: d.Credential.RefreshToken,
+					Expiry:       expiry,
+				},
+			}, nil
+		}
+	}
+	return nil, fmt.Errorf("oauth2/google: no such credentials for account %q", account)
+}
+
+// Client returns an HTTP client using Google Cloud SDK credentials to
+// authorize requests. The token will auto-refresh as necessary. The
+// underlying http.RoundTripper will be obtained using the provided
+// context. The returned client and its Transport should not be
+// modified.
+func (c *SDKConfig) Client(ctx context.Context) *http.Client {
+	return &http.Client{
+		Transport: &oauth2.Transport{
+			Source: c.TokenSource(ctx),
+		},
+	}
+}
+
+// TokenSource returns an oauth2.TokenSource that retrieve tokens from
+// Google Cloud SDK credentials using the provided context.
+// It will returns the current access token stored in the credentials,
+// and refresh it when it expires, but it won't update the credentials
+// with the new access token.
+func (c *SDKConfig) TokenSource(ctx context.Context) oauth2.TokenSource {
+	return c.conf.TokenSource(ctx, c.initialToken)
+}
+
+// Scopes are the OAuth 2.0 scopes the current account is authorized for.
+func (c *SDKConfig) Scopes() []string {
+	return c.conf.Scopes
+}
+
+func parseINI(ini io.Reader) (map[string]map[string]string, error) {
+	result := map[string]map[string]string{
+		"": {}, // root section
+	}
+	scanner := bufio.NewScanner(ini)
+	currentSection := ""
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if strings.HasPrefix(line, ";") {
+			// comment.
+			continue
+		}
+		if strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]") {
+			currentSection = strings.TrimSpace(line[1 : len(line)-1])
+			result[currentSection] = map[string]string{}
+			continue
+		}
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) == 2 && parts[0] != "" {
+			result[currentSection][strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("error scanning ini: %v", err)
+	}
+	return result, nil
+}
+
+// sdkConfigPath tries to guess where the gcloud config is located.
+// It can be overridden during tests.
+var sdkConfigPath = func() (string, error) {
+	if runtime.GOOS == "windows" {
+		return filepath.Join(os.Getenv("APPDATA"), "gcloud"), nil
+	}
+	homeDir := guessUnixHomeDir()
+	if homeDir == "" {
+		return "", errors.New("unable to get current user home directory: os/user lookup failed; $HOME is empty")
+	}
+	return filepath.Join(homeDir, ".config", "gcloud"), nil
+}
+
+func guessUnixHomeDir() string {
+	// Prefer $HOME over user.Current due to glibc bug: golang.org/issue/13470
+	if v := os.Getenv("HOME"); v != "" {
+		return v
+	}
+	// Else, fall back to user.Current:
+	if u, err := user.Current(); err == nil {
+		return u.HomeDir
+	}
+	return ""
+}