feat: gitea client

vendor/google.golang.org/api/internal/cba.go

@@ -0,0 +1,318 @@
+// Copyright 2020 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// cba.go (certificate-based access) contains utils for implementing Device Certificate
+// Authentication according to https://google.aip.dev/auth/4114 and Default Credentials
+// for Google Cloud Virtual Environments according to https://google.aip.dev/auth/4115.
+//
+// The overall logic for DCA is as follows:
+//  1. If both endpoint override and client certificate are specified, use them as is.
+//  2. If user does not specify client certificate, we will attempt to use default
+//     client certificate.
+//  3. If user does not specify endpoint override, we will use defaultMtlsEndpoint if
+//     client certificate is available and defaultEndpoint otherwise.
+//
+// Implications of the above logic:
+//  1. If the user specifies a non-mTLS endpoint override but client certificate is
+//     available, we will pass along the cert anyway and let the server decide what to do.
+//  2. If the user specifies an mTLS endpoint override but client certificate is not
+//     available, we will not fail-fast, but let backend throw error when connecting.
+//
+// If running within Google's cloud environment, and client certificate is not specified
+// and not available through DCA, we will try mTLS with credentials held by
+// the Secure Session Agent, which is part of Google's cloud infrastructure.
+//
+// We would like to avoid introducing client-side logic that parses whether the
+// endpoint override is an mTLS url, since the url pattern may change at anytime.
+//
+// This package is not intended for use by end developers. Use the
+// google.golang.org/api/option package to configure API clients.
+
+// Package internal supports the options and transport packages.
+package internal
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"net"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/google/s2a-go"
+	"github.com/google/s2a-go/fallback"
+	"google.golang.org/api/internal/cert"
+	"google.golang.org/grpc/credentials"
+)
+
+const (
+	mTLSModeAlways = "always"
+	mTLSModeNever  = "never"
+	mTLSModeAuto   = "auto"
+
+	// Experimental: if true, the code will try MTLS with S2A as the default for transport security. Default value is false.
+	googleAPIUseS2AEnv = "EXPERIMENTAL_GOOGLE_API_USE_S2A"
+
+	universeDomainPlaceholder = "UNIVERSE_DOMAIN"
+)
+
+var (
+	errUniverseNotSupportedMTLS = errors.New("mTLS is not supported in any universe other than googleapis.com")
+)
+
+// getClientCertificateSourceAndEndpoint is a convenience function that invokes
+// getClientCertificateSource and getEndpoint sequentially and returns the client
+// cert source and endpoint as a tuple.
+func getClientCertificateSourceAndEndpoint(settings *DialSettings) (cert.Source, string, error) {
+	clientCertSource, err := getClientCertificateSource(settings)
+	if err != nil {
+		return nil, "", err
+	}
+	endpoint, err := getEndpoint(settings, clientCertSource)
+	if err != nil {
+		return nil, "", err
+	}
+	// TODO(chrisdsmith): https://github.com/googleapis/google-api-go-client/issues/2359
+	if settings.Endpoint == "" && !settings.IsUniverseDomainGDU() && settings.DefaultEndpointTemplate != "" {
+		// TODO(chrisdsmith): https://github.com/googleapis/google-api-go-client/issues/2359
+		// if settings.DefaultEndpointTemplate == "" {
+		// 	return nil, "", errors.New("internaloption.WithDefaultEndpointTemplate is required if option.WithUniverseDomain is not googleapis.com")
+		// }
+		endpoint = resolvedDefaultEndpoint(settings)
+	}
+	return clientCertSource, endpoint, nil
+}
+
+type transportConfig struct {
+	clientCertSource cert.Source // The client certificate source.
+	endpoint         string      // The corresponding endpoint to use based on client certificate source.
+	s2aAddress       string      // The S2A address if it can be used, otherwise an empty string.
+	s2aMTLSEndpoint  string      // The MTLS endpoint to use with S2A.
+}
+
+func getTransportConfig(settings *DialSettings) (*transportConfig, error) {
+	clientCertSource, endpoint, err := getClientCertificateSourceAndEndpoint(settings)
+	if err != nil {
+		return nil, err
+	}
+	defaultTransportConfig := transportConfig{
+		clientCertSource: clientCertSource,
+		endpoint:         endpoint,
+		s2aAddress:       "",
+		s2aMTLSEndpoint:  "",
+	}
+
+	if !shouldUseS2A(clientCertSource, settings) {
+		return &defaultTransportConfig, nil
+	}
+	if !settings.IsUniverseDomainGDU() {
+		return nil, errUniverseNotSupportedMTLS
+	}
+
+	s2aAddress := GetS2AAddress()
+	if s2aAddress == "" {
+		return &defaultTransportConfig, nil
+	}
+	return &transportConfig{
+		clientCertSource: clientCertSource,
+		endpoint:         endpoint,
+		s2aAddress:       s2aAddress,
+		s2aMTLSEndpoint:  settings.DefaultMTLSEndpoint,
+	}, nil
+}
+
+// getClientCertificateSource returns a default client certificate source, if
+// not provided by the user.
+//
+// A nil default source can be returned if the source does not exist. Any exceptions
+// encountered while initializing the default source will be reported as client
+// error (ex. corrupt metadata file).
+//
+// Important Note: For now, the environment variable GOOGLE_API_USE_CLIENT_CERTIFICATE
+// must be set to "true" to allow certificate to be used (including user provided
+// certificates). For details, see AIP-4114.
+func getClientCertificateSource(settings *DialSettings) (cert.Source, error) {
+	if !isClientCertificateEnabled() {
+		return nil, nil
+	} else if settings.ClientCertSource != nil {
+		return settings.ClientCertSource, nil
+	} else {
+		return cert.DefaultSource()
+	}
+}
+
+func isClientCertificateEnabled() bool {
+	useClientCert := os.Getenv("GOOGLE_API_USE_CLIENT_CERTIFICATE")
+	// TODO(andyrzhao): Update default to return "true" after DCA feature is fully released.
+	return strings.ToLower(useClientCert) == "true"
+}
+
+// getEndpoint returns the endpoint for the service, taking into account the
+// user-provided endpoint override "settings.Endpoint".
+//
+// If no endpoint override is specified, we will either return the default endpoint or
+// the default mTLS endpoint if a client certificate is available.
+//
+// You can override the default endpoint choice (mtls vs. regular) by setting the
+// GOOGLE_API_USE_MTLS_ENDPOINT environment variable.
+//
+// If the endpoint override is an address (host:port) rather than full base
+// URL (ex. https://...), then the user-provided address will be merged into
+// the default endpoint. For example, WithEndpoint("myhost:8000") and
+// WithDefaultEndpoint("https://foo.com/bar/baz") will return "https://myhost:8080/bar/baz"
+func getEndpoint(settings *DialSettings, clientCertSource cert.Source) (string, error) {
+	if settings.Endpoint == "" {
+		if isMTLS(clientCertSource) {
+			if !settings.IsUniverseDomainGDU() {
+				return "", errUniverseNotSupportedMTLS
+			}
+			return settings.DefaultMTLSEndpoint, nil
+		}
+		return resolvedDefaultEndpoint(settings), nil
+	}
+	if strings.Contains(settings.Endpoint, "://") {
+		// User passed in a full URL path, use it verbatim.
+		return settings.Endpoint, nil
+	}
+	if resolvedDefaultEndpoint(settings) == "" {
+		// If DefaultEndpoint is not configured, use the user provided endpoint verbatim.
+		// This allows a naked "host[:port]" URL to be used with GRPC Direct Path.
+		return settings.Endpoint, nil
+	}
+
+	// Assume user-provided endpoint is host[:port], merge it with the default endpoint.
+	return mergeEndpoints(resolvedDefaultEndpoint(settings), settings.Endpoint)
+}
+
+func isMTLS(clientCertSource cert.Source) bool {
+	mtlsMode := getMTLSMode()
+	return mtlsMode == mTLSModeAlways || (clientCertSource != nil && mtlsMode == mTLSModeAuto)
+}
+
+// resolvedDefaultEndpoint returns the DefaultEndpointTemplate merged with the
+// Universe Domain if the DefaultEndpointTemplate is set, otherwise returns the
+// deprecated DefaultEndpoint value.
+func resolvedDefaultEndpoint(settings *DialSettings) string {
+	if settings.DefaultEndpointTemplate == "" {
+		return settings.DefaultEndpoint
+	}
+	return strings.Replace(settings.DefaultEndpointTemplate, universeDomainPlaceholder, settings.GetUniverseDomain(), 1)
+}
+
+func getMTLSMode() string {
+	mode := os.Getenv("GOOGLE_API_USE_MTLS_ENDPOINT")
+	if mode == "" {
+		mode = os.Getenv("GOOGLE_API_USE_MTLS") // Deprecated.
+	}
+	if mode == "" {
+		return mTLSModeAuto
+	}
+	return strings.ToLower(mode)
+}
+
+func mergeEndpoints(baseURL, newHost string) (string, error) {
+	u, err := url.Parse(fixScheme(baseURL))
+	if err != nil {
+		return "", err
+	}
+	return strings.Replace(baseURL, u.Host, newHost, 1), nil
+}
+
+func fixScheme(baseURL string) string {
+	if !strings.Contains(baseURL, "://") {
+		return "https://" + baseURL
+	}
+	return baseURL
+}
+
+// GetGRPCTransportConfigAndEndpoint returns an instance of credentials.TransportCredentials, and the
+// corresponding endpoint to use for GRPC client.
+func GetGRPCTransportConfigAndEndpoint(settings *DialSettings) (credentials.TransportCredentials, string, error) {
+	config, err := getTransportConfig(settings)
+	if err != nil {
+		return nil, "", err
+	}
+
+	defaultTransportCreds := credentials.NewTLS(&tls.Config{
+		GetClientCertificate: config.clientCertSource,
+	})
+	if config.s2aAddress == "" {
+		return defaultTransportCreds, config.endpoint, nil
+	}
+
+	var fallbackOpts *s2a.FallbackOptions
+	// In case of S2A failure, fall back to the endpoint that would've been used without S2A.
+	if fallbackHandshake, err := fallback.DefaultFallbackClientHandshakeFunc(config.endpoint); err == nil {
+		fallbackOpts = &s2a.FallbackOptions{
+			FallbackClientHandshakeFunc: fallbackHandshake,
+		}
+	}
+
+	s2aTransportCreds, err := s2a.NewClientCreds(&s2a.ClientOptions{
+		S2AAddress:   config.s2aAddress,
+		FallbackOpts: fallbackOpts,
+	})
+	if err != nil {
+		// Use default if we cannot initialize S2A client transport credentials.
+		return defaultTransportCreds, config.endpoint, nil
+	}
+	return s2aTransportCreds, config.s2aMTLSEndpoint, nil
+}
+
+// GetHTTPTransportConfigAndEndpoint returns a client certificate source, a function for dialing MTLS with S2A,
+// and the endpoint to use for HTTP client.
+func GetHTTPTransportConfigAndEndpoint(settings *DialSettings) (cert.Source, func(context.Context, string, string) (net.Conn, error), string, error) {
+	config, err := getTransportConfig(settings)
+	if err != nil {
+		return nil, nil, "", err
+	}
+
+	if config.s2aAddress == "" {
+		return config.clientCertSource, nil, config.endpoint, nil
+	}
+
+	var fallbackOpts *s2a.FallbackOptions
+	// In case of S2A failure, fall back to the endpoint that would've been used without S2A.
+	if fallbackURL, err := url.Parse(config.endpoint); err == nil {
+		if fallbackDialer, fallbackServerAddr, err := fallback.DefaultFallbackDialerAndAddress(fallbackURL.Hostname()); err == nil {
+			fallbackOpts = &s2a.FallbackOptions{
+				FallbackDialer: &s2a.FallbackDialer{
+					Dialer:     fallbackDialer,
+					ServerAddr: fallbackServerAddr,
+				},
+			}
+		}
+	}
+
+	dialTLSContextFunc := s2a.NewS2ADialTLSContextFunc(&s2a.ClientOptions{
+		S2AAddress:   config.s2aAddress,
+		FallbackOpts: fallbackOpts,
+	})
+	return nil, dialTLSContextFunc, config.s2aMTLSEndpoint, nil
+}
+
+func shouldUseS2A(clientCertSource cert.Source, settings *DialSettings) bool {
+	// If client cert is found, use that over S2A.
+	if clientCertSource != nil {
+		return false
+	}
+	// If EXPERIMENTAL_GOOGLE_API_USE_S2A is not set to true, skip S2A.
+	if !isGoogleS2AEnabled() {
+		return false
+	}
+	// If DefaultMTLSEndpoint is not set or has endpoint override, skip S2A.
+	if settings.DefaultMTLSEndpoint == "" || settings.Endpoint != "" {
+		return false
+	}
+	// If custom HTTP client is provided, skip S2A.
+	if settings.HTTPClient != nil {
+		return false
+	}
+	return !settings.EnableDirectPath && !settings.EnableDirectPathXds
+}
+
+func isGoogleS2AEnabled() bool {
+	return strings.ToLower(os.Getenv(googleAPIUseS2AEnv)) == "true"
+}

vendor/google.golang.org/api/internal/cert/default_cert.go

@@ -0,0 +1,58 @@
+// Copyright 2020 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package cert contains certificate tools for Google API clients.
+// This package is intended to be used with crypto/tls.Config.GetClientCertificate.
+//
+// The certificates can be used to satisfy Google's Endpoint Validation.
+// See https://cloud.google.com/endpoint-verification/docs/overview
+//
+// This package is not intended for use by end developers. Use the
+// google.golang.org/api/option package to configure API clients.
+package cert
+
+import (
+	"crypto/tls"
+	"errors"
+	"sync"
+)
+
+// defaultCertData holds all the variables pertaining to
+// the default certficate source created by DefaultSource.
+//
+// A singleton model is used to allow the source to be reused
+// by the transport layer.
+type defaultCertData struct {
+	once   sync.Once
+	source Source
+	err    error
+}
+
+var (
+	defaultCert defaultCertData
+)
+
+// Source is a function that can be passed into crypto/tls.Config.GetClientCertificate.
+type Source func(*tls.CertificateRequestInfo) (*tls.Certificate, error)
+
+// errSourceUnavailable is a sentinel error to indicate certificate source is unavailable.
+var errSourceUnavailable = errors.New("certificate source is unavailable")
+
+// DefaultSource returns a certificate source using the preferred EnterpriseCertificateProxySource.
+// If EnterpriseCertificateProxySource is not available, fall back to the legacy SecureConnectSource.
+//
+// If neither source is available (due to missing configurations), a nil Source and a nil Error are
+// returned to indicate that a default certificate source is unavailable.
+func DefaultSource() (Source, error) {
+	defaultCert.once.Do(func() {
+		defaultCert.source, defaultCert.err = NewEnterpriseCertificateProxySource("")
+		if errors.Is(defaultCert.err, errSourceUnavailable) {
+			defaultCert.source, defaultCert.err = NewSecureConnectSource("")
+			if errors.Is(defaultCert.err, errSourceUnavailable) {
+				defaultCert.source, defaultCert.err = nil, nil
+			}
+		}
+	})
+	return defaultCert.source, defaultCert.err
+}

vendor/google.golang.org/api/internal/cert/enterprise_cert.go

@@ -0,0 +1,54 @@
+// Copyright 2022 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package cert contains certificate tools for Google API clients.
+// This package is intended to be used with crypto/tls.Config.GetClientCertificate.
+//
+// The certificates can be used to satisfy Google's Endpoint Validation.
+// See https://cloud.google.com/endpoint-verification/docs/overview
+//
+// This package is not intended for use by end developers. Use the
+// google.golang.org/api/option package to configure API clients.
+package cert
+
+import (
+	"crypto/tls"
+	"errors"
+
+	"github.com/googleapis/enterprise-certificate-proxy/client"
+)
+
+type ecpSource struct {
+	key *client.Key
+}
+
+// NewEnterpriseCertificateProxySource creates a certificate source
+// using the Enterprise Certificate Proxy client, which delegates
+// certifcate related operations to an OS-specific "signer binary"
+// that communicates with the native keystore (ex. keychain on MacOS).
+//
+// The configFilePath points to a config file containing relevant parameters
+// such as the certificate issuer and the location of the signer binary.
+// If configFilePath is empty, the client will attempt to load the config from
+// a well-known gcloud location.
+func NewEnterpriseCertificateProxySource(configFilePath string) (Source, error) {
+	key, err := client.Cred(configFilePath)
+	if err != nil {
+		if errors.Is(err, client.ErrCredUnavailable) {
+			return nil, errSourceUnavailable
+		}
+		return nil, err
+	}
+
+	return (&ecpSource{
+		key: key,
+	}).getClientCertificate, nil
+}
+
+func (s *ecpSource) getClientCertificate(info *tls.CertificateRequestInfo) (*tls.Certificate, error) {
+	var cert tls.Certificate
+	cert.PrivateKey = s.key
+	cert.Certificate = s.key.CertificateChain()
+	return &cert, nil
+}

vendor/google.golang.org/api/internal/cert/secureconnect_cert.go

@@ -0,0 +1,122 @@
+// Copyright 2022 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package cert contains certificate tools for Google API clients.
+// This package is intended to be used with crypto/tls.Config.GetClientCertificate.
+//
+// The certificates can be used to satisfy Google's Endpoint Validation.
+// See https://cloud.google.com/endpoint-verification/docs/overview
+//
+// This package is not intended for use by end developers. Use the
+// google.golang.org/api/option package to configure API clients.
+package cert
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"os/user"
+	"path/filepath"
+	"sync"
+	"time"
+)
+
+const (
+	metadataPath = ".secureConnect"
+	metadataFile = "context_aware_metadata.json"
+)
+
+type secureConnectSource struct {
+	metadata secureConnectMetadata
+
+	// Cache the cert to avoid executing helper command repeatedly.
+	cachedCertMutex sync.Mutex
+	cachedCert      *tls.Certificate
+}
+
+type secureConnectMetadata struct {
+	Cmd []string `json:"cert_provider_command"`
+}
+
+// NewSecureConnectSource creates a certificate source using
+// the Secure Connect Helper and its associated metadata file.
+//
+// The configFilePath points to the location of the context aware metadata file.
+// If configFilePath is empty, use the default context aware metadata location.
+func NewSecureConnectSource(configFilePath string) (Source, error) {
+	if configFilePath == "" {
+		user, err := user.Current()
+		if err != nil {
+			// Error locating the default config means Secure Connect is not supported.
+			return nil, errSourceUnavailable
+		}
+		configFilePath = filepath.Join(user.HomeDir, metadataPath, metadataFile)
+	}
+
+	file, err := os.ReadFile(configFilePath)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			// Config file missing means Secure Connect is not supported.
+			return nil, errSourceUnavailable
+		}
+		return nil, err
+	}
+
+	var metadata secureConnectMetadata
+	if err := json.Unmarshal(file, &metadata); err != nil {
+		return nil, fmt.Errorf("cert: could not parse JSON in %q: %w", configFilePath, err)
+	}
+	if err := validateMetadata(metadata); err != nil {
+		return nil, fmt.Errorf("cert: invalid config in %q: %w", configFilePath, err)
+	}
+	return (&secureConnectSource{
+		metadata: metadata,
+	}).getClientCertificate, nil
+}
+
+func validateMetadata(metadata secureConnectMetadata) error {
+	if len(metadata.Cmd) == 0 {
+		return errors.New("empty cert_provider_command")
+	}
+	return nil
+}
+
+func (s *secureConnectSource) getClientCertificate(info *tls.CertificateRequestInfo) (*tls.Certificate, error) {
+	s.cachedCertMutex.Lock()
+	defer s.cachedCertMutex.Unlock()
+	if s.cachedCert != nil && !isCertificateExpired(s.cachedCert) {
+		return s.cachedCert, nil
+	}
+	// Expand OS environment variables in the cert provider command such as "$HOME".
+	for i := 0; i < len(s.metadata.Cmd); i++ {
+		s.metadata.Cmd[i] = os.ExpandEnv(s.metadata.Cmd[i])
+	}
+	command := s.metadata.Cmd
+	data, err := exec.Command(command[0], command[1:]...).Output()
+	if err != nil {
+		return nil, err
+	}
+	cert, err := tls.X509KeyPair(data, data)
+	if err != nil {
+		return nil, err
+	}
+	s.cachedCert = &cert
+	return &cert, nil
+}
+
+// isCertificateExpired returns true if the given cert is expired or invalid.
+func isCertificateExpired(cert *tls.Certificate) bool {
+	if len(cert.Certificate) == 0 {
+		return true
+	}
+	parsed, err := x509.ParseCertificate(cert.Certificate[0])
+	if err != nil {
+		return true
+	}
+	return time.Now().After(parsed.NotAfter)
+}

vendor/google.golang.org/api/internal/conn_pool.go

@@ -0,0 +1,30 @@
+// Copyright 2020 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package internal
+
+import (
+	"google.golang.org/grpc"
+)
+
+// ConnPool is a pool of grpc.ClientConns.
+type ConnPool interface {
+	// Conn returns a ClientConn from the pool.
+	//
+	// Conns aren't returned to the pool.
+	Conn() *grpc.ClientConn
+
+	// Num returns the number of connections in the pool.
+	//
+	// It will always return the same value.
+	Num() int
+
+	// Close closes every ClientConn in the pool.
+	//
+	// The error returned by Close may be a single error or multiple errors.
+	Close() error
+
+	// ConnPool implements grpc.ClientConnInterface to enable it to be used directly with generated proto stubs.
+	grpc.ClientConnInterface
+}

vendor/google.golang.org/api/internal/creds.go

@@ -0,0 +1,315 @@
+// Copyright 2017 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package internal
+
+import (
+	"context"
+	"crypto/tls"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"cloud.google.com/go/auth/credentials"
+	"cloud.google.com/go/auth/oauth2adapt"
+	"golang.org/x/oauth2"
+	"google.golang.org/api/internal/cert"
+	"google.golang.org/api/internal/impersonate"
+
+	"golang.org/x/oauth2/google"
+)
+
+const quotaProjectEnvVar = "GOOGLE_CLOUD_QUOTA_PROJECT"
+
+// Creds returns credential information obtained from DialSettings, or if none, then
+// it returns default credential information.
+func Creds(ctx context.Context, ds *DialSettings) (*google.Credentials, error) {
+	if ds.IsNewAuthLibraryEnabled() {
+		return credsNewAuth(ctx, ds)
+	}
+	creds, err := baseCreds(ctx, ds)
+	if err != nil {
+		return nil, err
+	}
+	if ds.ImpersonationConfig != nil {
+		return impersonateCredentials(ctx, creds, ds)
+	}
+	return creds, nil
+}
+
+// GetOAuth2Configuration determines configurations for the OAuth2 transport, which is separate from the API transport.
+// The OAuth2 transport and endpoint will be configured for mTLS if applicable.
+func GetOAuth2Configuration(ctx context.Context, settings *DialSettings) (string, *http.Client, error) {
+	clientCertSource, err := getClientCertificateSource(settings)
+	if err != nil {
+		return "", nil, err
+	}
+	tokenURL := oAuth2Endpoint(clientCertSource)
+	var oauth2Client *http.Client
+	if clientCertSource != nil {
+		tlsConfig := &tls.Config{
+			GetClientCertificate: clientCertSource,
+		}
+		oauth2Client = customHTTPClient(tlsConfig)
+	} else {
+		oauth2Client = oauth2.NewClient(ctx, nil)
+	}
+	return tokenURL, oauth2Client, nil
+}
+
+func credsNewAuth(ctx context.Context, settings *DialSettings) (*google.Credentials, error) {
+	// Preserve old options behavior
+	if settings.InternalCredentials != nil {
+		return settings.InternalCredentials, nil
+	} else if settings.Credentials != nil {
+		return settings.Credentials, nil
+	} else if settings.TokenSource != nil {
+		return &google.Credentials{TokenSource: settings.TokenSource}, nil
+	}
+
+	if settings.AuthCredentials != nil {
+		return oauth2adapt.Oauth2CredentialsFromAuthCredentials(settings.AuthCredentials), nil
+	}
+
+	var useSelfSignedJWT bool
+	var aud string
+	var scopes []string
+	// If scoped JWTs are enabled user provided an aud, allow self-signed JWT.
+	if settings.EnableJwtWithScope || len(settings.Audiences) > 0 {
+		useSelfSignedJWT = true
+	}
+
+	if len(settings.Scopes) > 0 {
+		scopes = make([]string, len(settings.Scopes))
+		copy(scopes, settings.Scopes)
+	}
+	if len(settings.Audiences) > 0 {
+		aud = settings.Audiences[0]
+	}
+	// Only default scopes if user did not also set an audience.
+	if len(settings.Scopes) == 0 && aud == "" && len(settings.DefaultScopes) > 0 {
+		scopes = make([]string, len(settings.DefaultScopes))
+		copy(scopes, settings.DefaultScopes)
+	}
+	if len(scopes) == 0 && aud == "" {
+		aud = settings.DefaultAudience
+	}
+
+	tokenURL, oauth2Client, err := GetOAuth2Configuration(ctx, settings)
+	if err != nil {
+		return nil, err
+	}
+	creds, err := credentials.DetectDefault(&credentials.DetectOptions{
+		Scopes:           scopes,
+		Audience:         aud,
+		CredentialsFile:  settings.CredentialsFile,
+		CredentialsJSON:  settings.CredentialsJSON,
+		UseSelfSignedJWT: useSelfSignedJWT,
+		TokenURL:         tokenURL,
+		Client:           oauth2Client,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return oauth2adapt.Oauth2CredentialsFromAuthCredentials(creds), nil
+}
+
+func baseCreds(ctx context.Context, ds *DialSettings) (*google.Credentials, error) {
+	if ds.InternalCredentials != nil {
+		return ds.InternalCredentials, nil
+	}
+	if ds.Credentials != nil {
+		return ds.Credentials, nil
+	}
+	if ds.CredentialsJSON != nil {
+		return credentialsFromJSON(ctx, ds.CredentialsJSON, ds)
+	}
+	if ds.CredentialsFile != "" {
+		data, err := os.ReadFile(ds.CredentialsFile)
+		if err != nil {
+			return nil, fmt.Errorf("cannot read credentials file: %v", err)
+		}
+		return credentialsFromJSON(ctx, data, ds)
+	}
+	if ds.TokenSource != nil {
+		return &google.Credentials{TokenSource: ds.TokenSource}, nil
+	}
+	cred, err := google.FindDefaultCredentials(ctx, ds.GetScopes()...)
+	if err != nil {
+		return nil, err
+	}
+	if len(cred.JSON) > 0 {
+		return credentialsFromJSON(ctx, cred.JSON, ds)
+	}
+	// For GAE and GCE, the JSON is empty so return the default credentials directly.
+	return cred, nil
+}
+
+// JSON key file type.
+const (
+	serviceAccountKey = "service_account"
+)
+
+// credentialsFromJSON returns a google.Credentials from the JSON data
+//
+// - A self-signed JWT flow will be executed if the following conditions are
+// met:
+//
+//	(1) At least one of the following is true:
+//	    (a) Scope for self-signed JWT flow is enabled
+//	    (b) Audiences are explicitly provided by users
+//	(2) No service account impersontation
+//
+// - Otherwise, executes standard OAuth 2.0 flow
+// More details: google.aip.dev/auth/4111
+func credentialsFromJSON(ctx context.Context, data []byte, ds *DialSettings) (*google.Credentials, error) {
+	var params google.CredentialsParams
+	params.Scopes = ds.GetScopes()
+
+	tokenURL, oauth2Client, err := GetOAuth2Configuration(ctx, ds)
+	if err != nil {
+		return nil, err
+	}
+	params.TokenURL = tokenURL
+	ctx = context.WithValue(ctx, oauth2.HTTPClient, oauth2Client)
+
+	// By default, a standard OAuth 2.0 token source is created
+	cred, err := google.CredentialsFromJSONWithParams(ctx, data, params)
+	if err != nil {
+		return nil, err
+	}
+
+	// Override the token source to use self-signed JWT if conditions are met
+	isJWTFlow, err := isSelfSignedJWTFlow(data, ds)
+	if err != nil {
+		return nil, err
+	}
+	if isJWTFlow {
+		ts, err := selfSignedJWTTokenSource(data, ds)
+		if err != nil {
+			return nil, err
+		}
+		cred.TokenSource = ts
+	}
+
+	return cred, err
+}
+
+func oAuth2Endpoint(clientCertSource cert.Source) string {
+	if isMTLS(clientCertSource) {
+		return google.MTLSTokenURL
+	}
+	return google.Endpoint.TokenURL
+}
+
+func isSelfSignedJWTFlow(data []byte, ds *DialSettings) (bool, error) {
+	// For non-GDU universe domains, token exchange is impossible and services
+	// must support self-signed JWTs with scopes.
+	if !ds.IsUniverseDomainGDU() {
+		return typeServiceAccount(data)
+	}
+	if (ds.EnableJwtWithScope || ds.HasCustomAudience()) && ds.ImpersonationConfig == nil {
+		return typeServiceAccount(data)
+	}
+	return false, nil
+}
+
+// typeServiceAccount checks if JSON data is for a service account.
+func typeServiceAccount(data []byte) (bool, error) {
+	var f struct {
+		Type string `json:"type"`
+		// The remaining JSON fields are omitted because they are not used.
+	}
+	if err := json.Unmarshal(data, &f); err != nil {
+		return false, err
+	}
+	return f.Type == serviceAccountKey, nil
+}
+
+func selfSignedJWTTokenSource(data []byte, ds *DialSettings) (oauth2.TokenSource, error) {
+	if len(ds.GetScopes()) > 0 && !ds.HasCustomAudience() {
+		// Scopes are preferred in self-signed JWT unless the scope is not available
+		// or a custom audience is used.
+		return google.JWTAccessTokenSourceWithScope(data, ds.GetScopes()...)
+	} else if ds.GetAudience() != "" {
+		// Fallback to audience if scope is not provided
+		return google.JWTAccessTokenSourceFromJSON(data, ds.GetAudience())
+	} else {
+		return nil, errors.New("neither scopes or audience are available for the self-signed JWT")
+	}
+}
+
+// GetQuotaProject retrieves quota project with precedence being: client option,
+// environment variable, creds file.
+func GetQuotaProject(creds *google.Credentials, clientOpt string) string {
+	if clientOpt != "" {
+		return clientOpt
+	}
+	if env := os.Getenv(quotaProjectEnvVar); env != "" {
+		return env
+	}
+	if creds == nil {
+		return ""
+	}
+	var v struct {
+		QuotaProject string `json:"quota_project_id"`
+	}
+	if err := json.Unmarshal(creds.JSON, &v); err != nil {
+		return ""
+	}
+	return v.QuotaProject
+}
+
+func impersonateCredentials(ctx context.Context, creds *google.Credentials, ds *DialSettings) (*google.Credentials, error) {
+	if len(ds.ImpersonationConfig.Scopes) == 0 {
+		ds.ImpersonationConfig.Scopes = ds.GetScopes()
+	}
+	ts, err := impersonate.TokenSource(ctx, creds.TokenSource, ds.ImpersonationConfig)
+	if err != nil {
+		return nil, err
+	}
+	return &google.Credentials{
+		TokenSource: ts,
+		ProjectID:   creds.ProjectID,
+	}, nil
+}
+
+// customHTTPClient constructs an HTTPClient using the provided tlsConfig, to support mTLS.
+func customHTTPClient(tlsConfig *tls.Config) *http.Client {
+	trans := baseTransport()
+	trans.TLSClientConfig = tlsConfig
+	return &http.Client{Transport: trans}
+}
+
+func baseTransport() *http.Transport {
+	return &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+			DualStack: true,
+		}).DialContext,
+		MaxIdleConns:          100,
+		MaxIdleConnsPerHost:   100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+	}
+}
+
+// ErrUniverseNotMatch composes an error string from the provided universe
+// domain sources (DialSettings and Credentials, respectively).
+func ErrUniverseNotMatch(settingsUD, credsUD string) error {
+	return fmt.Errorf(
+		"the configured universe domain (%q) does not match the universe "+
+			"domain found in the credentials (%q). If you haven't configured "+
+			"WithUniverseDomain explicitly, \"googleapis.com\" is the default",
+		settingsUD,
+		credsUD)
+}

vendor/google.golang.org/api/internal/impersonate/impersonate.go

@@ -0,0 +1,127 @@
+// 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 impersonate is used to impersonate Google Credentials.
+package impersonate
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+// Config for generating impersonated credentials.
+type Config struct {
+	// Target is the service account to impersonate. Required.
+	Target string
+	// Scopes the impersonated credential should have. Required.
+	Scopes []string
+	// Delegates are the service accounts in a delegation chain. Each service
+	// account must be granted roles/iam.serviceAccountTokenCreator on the next
+	// service account in the chain. Optional.
+	Delegates []string
+}
+
+// TokenSource returns an impersonated TokenSource configured with the provided
+// config using ts as the base credential provider for making requests.
+func TokenSource(ctx context.Context, ts oauth2.TokenSource, config *Config) (oauth2.TokenSource, error) {
+	if len(config.Scopes) == 0 {
+		return nil, fmt.Errorf("impersonate: scopes must be provided")
+	}
+	its := impersonatedTokenSource{
+		ctx:  ctx,
+		ts:   ts,
+		name: formatIAMServiceAccountName(config.Target),
+		// Default to the longest acceptable value of one hour as the token will
+		// be refreshed automatically.
+		lifetime: "3600s",
+	}
+
+	its.delegates = make([]string, len(config.Delegates))
+	for i, v := range config.Delegates {
+		its.delegates[i] = formatIAMServiceAccountName(v)
+	}
+	its.scopes = make([]string, len(config.Scopes))
+	copy(its.scopes, config.Scopes)
+
+	return oauth2.ReuseTokenSource(nil, its), nil
+}
+
+func formatIAMServiceAccountName(name string) string {
+	return fmt.Sprintf("projects/-/serviceAccounts/%s", name)
+}
+
+type generateAccessTokenReq struct {
+	Delegates []string `json:"delegates,omitempty"`
+	Lifetime  string   `json:"lifetime,omitempty"`
+	Scope     []string `json:"scope,omitempty"`
+}
+
+type generateAccessTokenResp struct {
+	AccessToken string `json:"accessToken"`
+	ExpireTime  string `json:"expireTime"`
+}
+
+type impersonatedTokenSource struct {
+	ctx context.Context
+	ts  oauth2.TokenSource
+
+	name      string
+	lifetime  string
+	scopes    []string
+	delegates []string
+}
+
+// Token returns an impersonated Token.
+func (i impersonatedTokenSource) Token() (*oauth2.Token, error) {
+	hc := oauth2.NewClient(i.ctx, i.ts)
+	reqBody := generateAccessTokenReq{
+		Delegates: i.delegates,
+		Lifetime:  i.lifetime,
+		Scope:     i.scopes,
+	}
+	b, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("impersonate: unable to marshal request: %v", err)
+	}
+	url := fmt.Sprintf("https://iamcredentials.googleapis.com/v1/%s:generateAccessToken", i.name)
+	req, err := http.NewRequest("POST", url, bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("impersonate: unable to create request: %v", err)
+	}
+	req = req.WithContext(i.ctx)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := hc.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("impersonate: unable to generate access token: %v", err)
+	}
+	defer resp.Body.Close()
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	if err != nil {
+		return nil, fmt.Errorf("impersonate: unable to read body: %v", err)
+	}
+	if c := resp.StatusCode; c < 200 || c > 299 {
+		return nil, fmt.Errorf("impersonate: status code %d: %s", c, body)
+	}
+
+	var accessTokenResp generateAccessTokenResp
+	if err := json.Unmarshal(body, &accessTokenResp); err != nil {
+		return nil, fmt.Errorf("impersonate: unable to parse response: %v", err)
+	}
+	expiry, err := time.Parse(time.RFC3339, accessTokenResp.ExpireTime)
+	if err != nil {
+		return nil, fmt.Errorf("impersonate: unable to parse expiry: %v", err)
+	}
+	return &oauth2.Token{
+		AccessToken: accessTokenResp.AccessToken,
+		Expiry:      expiry,
+	}, nil
+}

vendor/google.golang.org/api/internal/s2a.go

@@ -0,0 +1,136 @@
+// Copyright 2023 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package internal
+
+import (
+	"encoding/json"
+	"log"
+	"sync"
+	"time"
+
+	"cloud.google.com/go/compute/metadata"
+)
+
+const configEndpointSuffix = "instance/platform-security/auto-mtls-configuration"
+
+// The period an MTLS config can be reused before needing refresh.
+var configExpiry = time.Hour
+
+// GetS2AAddress returns the S2A address to be reached via plaintext connection.
+func GetS2AAddress() string {
+	c, err := getMetadataMTLSAutoConfig().Config()
+	if err != nil {
+		return ""
+	}
+	if !c.Valid() {
+		return ""
+	}
+	return c.S2A.PlaintextAddress
+}
+
+type mtlsConfigSource interface {
+	Config() (*mtlsConfig, error)
+}
+
+// mdsMTLSAutoConfigSource is an instance of reuseMTLSConfigSource, with metadataMTLSAutoConfig as its config source.
+var (
+	mdsMTLSAutoConfigSource mtlsConfigSource
+	once                    sync.Once
+)
+
+// getMetadataMTLSAutoConfig returns mdsMTLSAutoConfigSource, which is backed by config from MDS with auto-refresh.
+func getMetadataMTLSAutoConfig() mtlsConfigSource {
+	once.Do(func() {
+		mdsMTLSAutoConfigSource = &reuseMTLSConfigSource{
+			src: &metadataMTLSAutoConfig{},
+		}
+	})
+	return mdsMTLSAutoConfigSource
+}
+
+// reuseMTLSConfigSource caches a valid version of mtlsConfig, and uses `src` to refresh upon config expiry.
+// It implements the mtlsConfigSource interface, so calling Config() on it returns an mtlsConfig.
+type reuseMTLSConfigSource struct {
+	src    mtlsConfigSource // src.Config() is called when config is expired
+	mu     sync.Mutex       // mutex guards config
+	config *mtlsConfig      // cached config
+}
+
+func (cs *reuseMTLSConfigSource) Config() (*mtlsConfig, error) {
+	cs.mu.Lock()
+	defer cs.mu.Unlock()
+
+	if cs.config.Valid() {
+		return cs.config, nil
+	}
+	c, err := cs.src.Config()
+	if err != nil {
+		return nil, err
+	}
+	cs.config = c
+	return c, nil
+}
+
+// metadataMTLSAutoConfig is an implementation of the interface mtlsConfigSource
+// It has the logic to query MDS and return an mtlsConfig
+type metadataMTLSAutoConfig struct{}
+
+var httpGetMetadataMTLSConfig = func() (string, error) {
+	return metadata.Get(configEndpointSuffix)
+}
+
+func (cs *metadataMTLSAutoConfig) Config() (*mtlsConfig, error) {
+	resp, err := httpGetMetadataMTLSConfig()
+	if err != nil {
+		log.Printf("querying MTLS config from MDS endpoint failed: %v", err)
+		return defaultMTLSConfig(), nil
+	}
+	var config mtlsConfig
+	err = json.Unmarshal([]byte(resp), &config)
+	if err != nil {
+		log.Printf("unmarshalling MTLS config from MDS endpoint failed: %v", err)
+		return defaultMTLSConfig(), nil
+	}
+
+	if config.S2A == nil {
+		log.Printf("returned MTLS config from MDS endpoint is invalid: %v", config)
+		return defaultMTLSConfig(), nil
+	}
+
+	// set new expiry
+	config.Expiry = time.Now().Add(configExpiry)
+	return &config, nil
+}
+
+func defaultMTLSConfig() *mtlsConfig {
+	return &mtlsConfig{
+		S2A: &s2aAddresses{
+			PlaintextAddress: "",
+			MTLSAddress:      "",
+		},
+		Expiry: time.Now().Add(configExpiry),
+	}
+}
+
+// s2aAddresses contains the plaintext and/or MTLS S2A addresses.
+type s2aAddresses struct {
+	// PlaintextAddress is the plaintext address to reach S2A
+	PlaintextAddress string `json:"plaintext_address"`
+	// MTLSAddress is the MTLS address to reach S2A
+	MTLSAddress string `json:"mtls_address"`
+}
+
+// mtlsConfig contains the configuration for establishing MTLS connections with Google APIs.
+type mtlsConfig struct {
+	S2A    *s2aAddresses `json:"s2a"`
+	Expiry time.Time
+}
+
+func (c *mtlsConfig) Valid() bool {
+	return c != nil && c.S2A != nil && !c.expired()
+}
+func (c *mtlsConfig) expired() bool {
+	return c.Expiry.Before(time.Now())
+}

vendor/google.golang.org/api/internal/settings.go

@@ -0,0 +1,243 @@
+// Copyright 2017 Google LLC.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package internal supports the options and transport packages.
+package internal
+
+import (
+	"crypto/tls"
+	"errors"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+
+	"cloud.google.com/go/auth"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+	"google.golang.org/api/internal/impersonate"
+	"google.golang.org/grpc"
+)
+
+const (
+	newAuthLibEnvVar        = "GOOGLE_API_GO_EXPERIMENTAL_ENABLE_NEW_AUTH_LIB"
+	newAuthLibDisabledEnVar = "GOOGLE_API_GO_EXPERIMENTAL_DISABLE_NEW_AUTH_LIB"
+	universeDomainEnvVar    = "GOOGLE_CLOUD_UNIVERSE_DOMAIN"
+	defaultUniverseDomain   = "googleapis.com"
+)
+
+// DialSettings holds information needed to establish a connection with a
+// Google API service.
+type DialSettings struct {
+	Endpoint                      string
+	DefaultEndpoint               string
+	DefaultEndpointTemplate       string
+	DefaultMTLSEndpoint           string
+	Scopes                        []string
+	DefaultScopes                 []string
+	EnableJwtWithScope            bool
+	TokenSource                   oauth2.TokenSource
+	Credentials                   *google.Credentials
+	CredentialsFile               string // if set, Token Source is ignored.
+	CredentialsJSON               []byte
+	InternalCredentials           *google.Credentials
+	UserAgent                     string
+	APIKey                        string
+	Audiences                     []string
+	DefaultAudience               string
+	HTTPClient                    *http.Client
+	GRPCDialOpts                  []grpc.DialOption
+	GRPCConn                      *grpc.ClientConn
+	GRPCConnPool                  ConnPool
+	GRPCConnPoolSize              int
+	NoAuth                        bool
+	TelemetryDisabled             bool
+	ClientCertSource              func(*tls.CertificateRequestInfo) (*tls.Certificate, error)
+	CustomClaims                  map[string]interface{}
+	SkipValidation                bool
+	ImpersonationConfig           *impersonate.Config
+	EnableDirectPath              bool
+	EnableDirectPathXds           bool
+	AllowNonDefaultServiceAccount bool
+	DefaultUniverseDomain         string
+	UniverseDomain                string
+	// Google API system parameters. For more information please read:
+	// https://cloud.google.com/apis/docs/system-parameters
+	QuotaProject  string
+	RequestReason string
+
+	// New Auth library Options
+	AuthCredentials      *auth.Credentials
+	EnableNewAuthLibrary bool
+}
+
+// GetScopes returns the user-provided scopes, if set, or else falls back to the
+// default scopes.
+func (ds *DialSettings) GetScopes() []string {
+	if len(ds.Scopes) > 0 {
+		return ds.Scopes
+	}
+	return ds.DefaultScopes
+}
+
+// GetAudience returns the user-provided audience, if set, or else falls back to the default audience.
+func (ds *DialSettings) GetAudience() string {
+	if ds.HasCustomAudience() {
+		return ds.Audiences[0]
+	}
+	return ds.DefaultAudience
+}
+
+// HasCustomAudience returns true if a custom audience is provided by users.
+func (ds *DialSettings) HasCustomAudience() bool {
+	return len(ds.Audiences) > 0
+}
+
+// IsNewAuthLibraryEnabled returns true if the new auth library should be used.
+func (ds *DialSettings) IsNewAuthLibraryEnabled() bool {
+	// Disabled env is for future rollouts to make sure there is a way to easily
+	// disable this behaviour once we switch in on by default.
+	if b, err := strconv.ParseBool(os.Getenv(newAuthLibDisabledEnVar)); err == nil && b {
+		return false
+	}
+	if ds.EnableNewAuthLibrary {
+		return true
+	}
+	if b, err := strconv.ParseBool(os.Getenv(newAuthLibEnvVar)); err == nil {
+		return b
+	}
+	return false
+}
+
+// Validate reports an error if ds is invalid.
+func (ds *DialSettings) Validate() error {
+	if ds.SkipValidation {
+		return nil
+	}
+	hasCreds := ds.APIKey != "" || ds.TokenSource != nil || ds.CredentialsFile != "" || ds.Credentials != nil
+	if ds.NoAuth && hasCreds {
+		return errors.New("options.WithoutAuthentication is incompatible with any option that provides credentials")
+	}
+	// Credentials should not appear with other options.
+	// We currently allow TokenSource and CredentialsFile to coexist.
+	// TODO(jba): make TokenSource & CredentialsFile an error (breaking change).
+	nCreds := 0
+	if ds.Credentials != nil {
+		nCreds++
+	}
+	if ds.CredentialsJSON != nil {
+		nCreds++
+	}
+	if ds.CredentialsFile != "" {
+		nCreds++
+	}
+	if ds.APIKey != "" {
+		nCreds++
+	}
+	if ds.TokenSource != nil {
+		nCreds++
+	}
+	if len(ds.Scopes) > 0 && len(ds.Audiences) > 0 {
+		return errors.New("WithScopes is incompatible with WithAudience")
+	}
+	// Accept only one form of credentials, except we allow TokenSource and CredentialsFile for backwards compatibility.
+	if nCreds > 1 && !(nCreds == 2 && ds.TokenSource != nil && ds.CredentialsFile != "") {
+		return errors.New("multiple credential options provided")
+	}
+	if ds.GRPCConn != nil && ds.GRPCConnPool != nil {
+		return errors.New("WithGRPCConn is incompatible with WithConnPool")
+	}
+	if ds.HTTPClient != nil && ds.GRPCConnPool != nil {
+		return errors.New("WithHTTPClient is incompatible with WithConnPool")
+	}
+	if ds.HTTPClient != nil && ds.GRPCConn != nil {
+		return errors.New("WithHTTPClient is incompatible with WithGRPCConn")
+	}
+	if ds.HTTPClient != nil && ds.GRPCDialOpts != nil {
+		return errors.New("WithHTTPClient is incompatible with gRPC dial options")
+	}
+	if ds.HTTPClient != nil && ds.QuotaProject != "" {
+		return errors.New("WithHTTPClient is incompatible with QuotaProject")
+	}
+	if ds.HTTPClient != nil && ds.RequestReason != "" {
+		return errors.New("WithHTTPClient is incompatible with RequestReason")
+	}
+	if ds.HTTPClient != nil && ds.ClientCertSource != nil {
+		return errors.New("WithHTTPClient is incompatible with WithClientCertSource")
+	}
+	if ds.ClientCertSource != nil && (ds.GRPCConn != nil || ds.GRPCConnPool != nil || ds.GRPCConnPoolSize != 0 || ds.GRPCDialOpts != nil) {
+		return errors.New("WithClientCertSource is currently only supported for HTTP. gRPC settings are incompatible")
+	}
+	if ds.ImpersonationConfig != nil && len(ds.ImpersonationConfig.Scopes) == 0 && len(ds.Scopes) == 0 {
+		return errors.New("WithImpersonatedCredentials requires scopes being provided")
+	}
+	return nil
+}
+
+// GetDefaultUniverseDomain returns the Google default universe domain
+// ("googleapis.com").
+func (ds *DialSettings) GetDefaultUniverseDomain() string {
+	return defaultUniverseDomain
+}
+
+// GetUniverseDomain returns the default service domain for a given Cloud
+// universe, with the following precedence:
+//
+// 1. A non-empty option.WithUniverseDomain.
+// 2. A non-empty environment variable GOOGLE_CLOUD_UNIVERSE_DOMAIN.
+// 3. The default value "googleapis.com".
+func (ds *DialSettings) GetUniverseDomain() string {
+	if ds.UniverseDomain != "" {
+		return ds.UniverseDomain
+	}
+	if envUD := os.Getenv(universeDomainEnvVar); envUD != "" {
+		return envUD
+	}
+	return defaultUniverseDomain
+}
+
+// IsUniverseDomainGDU returns true if the universe domain is the default Google
+// universe ("googleapis.com").
+func (ds *DialSettings) IsUniverseDomainGDU() bool {
+	return ds.GetUniverseDomain() == defaultUniverseDomain
+}
+
+// GetUniverseDomain returns the default service domain for a given Cloud
+// universe, from google.Credentials, for comparison with the value returned by
+// (*DialSettings).GetUniverseDomain. This wrapper function should be removed
+// to close https://github.com/googleapis/google-api-go-client/issues/2399.
+func GetUniverseDomain(creds *google.Credentials) (string, error) {
+	timer := time.NewTimer(time.Second)
+	defer timer.Stop()
+	errors := make(chan error)
+	results := make(chan string)
+
+	go func() {
+		result, err := creds.GetUniverseDomain()
+		if err != nil {
+			errors <- err
+			return
+		}
+		results <- result
+	}()
+
+	select {
+	case <-errors:
+		// An error that is returned before the timer expires is likely to be
+		// connection refused. Temporarily (2024-03-21) return the GDU domain.
+		return defaultUniverseDomain, nil
+	case res := <-results:
+		return res, nil
+	case <-timer.C: // Timer is expired.
+		// If err or res was not returned, it means that creds.GetUniverseDomain()
+		// did not complete in 1s. Assume that MDS is likely never responding to
+		// the endpoint and will timeout. This is the source of issues such as
+		// https://github.com/googleapis/google-cloud-go/issues/9350.
+		// Temporarily (2024-02-02) return the GDU domain. Restore the original
+		// calls to creds.GetUniverseDomain() in grpc/dial.go and http/dial.go
+		// and remove this method to close
+		// https://github.com/googleapis/google-api-go-client/issues/2399.
+		return defaultUniverseDomain, nil
+	}
+}

vendor/google.golang.org/api/internal/third_party/uritemplates/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2013 Joshua Tacoma. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/google.golang.org/api/internal/third_party/uritemplates/METADATA

@@ -0,0 +1,14 @@
+name: "uritemplates"
+description:
+    "Package uritemplates is a level 4 implementation of RFC 6570 (URI "
+    "Template, http://tools.ietf.org/html/rfc6570)."
+
+third_party {
+  url {
+    type: GIT
+    value: "https://github.com/jtacoma/uritemplates"
+  }
+  version: "0.1"
+  last_upgrade_date { year: 2014 month: 8 day: 18 }
+  license_type: NOTICE
+}

vendor/google.golang.org/api/internal/third_party/uritemplates/uritemplates.go

@@ -0,0 +1,248 @@
+// Copyright 2013 Joshua Tacoma. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package uritemplates is a level 3 implementation of RFC 6570 (URI
+// Template, http://tools.ietf.org/html/rfc6570).
+// uritemplates does not support composite values (in Go: slices or maps)
+// and so does not qualify as a level 4 implementation.
+package uritemplates
+
+import (
+	"bytes"
+	"errors"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+var (
+	unreserved = regexp.MustCompile("[^A-Za-z0-9\\-._~]")
+	reserved   = regexp.MustCompile("[^A-Za-z0-9\\-._~:/?#[\\]@!$&'()*+,;=]")
+	validname  = regexp.MustCompile("^([A-Za-z0-9_\\.]|%[0-9A-Fa-f][0-9A-Fa-f])+$")
+	hex        = []byte("0123456789ABCDEF")
+)
+
+func pctEncode(src []byte) []byte {
+	dst := make([]byte, len(src)*3)
+	for i, b := range src {
+		buf := dst[i*3 : i*3+3]
+		buf[0] = 0x25
+		buf[1] = hex[b/16]
+		buf[2] = hex[b%16]
+	}
+	return dst
+}
+
+// pairWriter is a convenience struct which allows escaped and unescaped
+// versions of the template to be written in parallel.
+type pairWriter struct {
+	escaped, unescaped bytes.Buffer
+}
+
+// Write writes the provided string directly without any escaping.
+func (w *pairWriter) Write(s string) {
+	w.escaped.WriteString(s)
+	w.unescaped.WriteString(s)
+}
+
+// Escape writes the provided string, escaping the string for the
+// escaped output.
+func (w *pairWriter) Escape(s string, allowReserved bool) {
+	w.unescaped.WriteString(s)
+	if allowReserved {
+		w.escaped.Write(reserved.ReplaceAllFunc([]byte(s), pctEncode))
+	} else {
+		w.escaped.Write(unreserved.ReplaceAllFunc([]byte(s), pctEncode))
+	}
+}
+
+// Escaped returns the escaped string.
+func (w *pairWriter) Escaped() string {
+	return w.escaped.String()
+}
+
+// Unescaped returns the unescaped string.
+func (w *pairWriter) Unescaped() string {
+	return w.unescaped.String()
+}
+
+// A uriTemplate is a parsed representation of a URI template.
+type uriTemplate struct {
+	raw   string
+	parts []templatePart
+}
+
+// parse parses a URI template string into a uriTemplate object.
+func parse(rawTemplate string) (*uriTemplate, error) {
+	split := strings.Split(rawTemplate, "{")
+	parts := make([]templatePart, len(split)*2-1)
+	for i, s := range split {
+		if i == 0 {
+			if strings.Contains(s, "}") {
+				return nil, errors.New("unexpected }")
+			}
+			parts[i].raw = s
+			continue
+		}
+		subsplit := strings.Split(s, "}")
+		if len(subsplit) != 2 {
+			return nil, errors.New("malformed template")
+		}
+		expression := subsplit[0]
+		var err error
+		parts[i*2-1], err = parseExpression(expression)
+		if err != nil {
+			return nil, err
+		}
+		parts[i*2].raw = subsplit[1]
+	}
+	return &uriTemplate{
+		raw:   rawTemplate,
+		parts: parts,
+	}, nil
+}
+
+type templatePart struct {
+	raw           string
+	terms         []templateTerm
+	first         string
+	sep           string
+	named         bool
+	ifemp         string
+	allowReserved bool
+}
+
+type templateTerm struct {
+	name     string
+	explode  bool
+	truncate int
+}
+
+func parseExpression(expression string) (result templatePart, err error) {
+	switch expression[0] {
+	case '+':
+		result.sep = ","
+		result.allowReserved = true
+		expression = expression[1:]
+	case '.':
+		result.first = "."
+		result.sep = "."
+		expression = expression[1:]
+	case '/':
+		result.first = "/"
+		result.sep = "/"
+		expression = expression[1:]
+	case ';':
+		result.first = ";"
+		result.sep = ";"
+		result.named = true
+		expression = expression[1:]
+	case '?':
+		result.first = "?"
+		result.sep = "&"
+		result.named = true
+		result.ifemp = "="
+		expression = expression[1:]
+	case '&':
+		result.first = "&"
+		result.sep = "&"
+		result.named = true
+		result.ifemp = "="
+		expression = expression[1:]
+	case '#':
+		result.first = "#"
+		result.sep = ","
+		result.allowReserved = true
+		expression = expression[1:]
+	default:
+		result.sep = ","
+	}
+	rawterms := strings.Split(expression, ",")
+	result.terms = make([]templateTerm, len(rawterms))
+	for i, raw := range rawterms {
+		result.terms[i], err = parseTerm(raw)
+		if err != nil {
+			break
+		}
+	}
+	return result, err
+}
+
+func parseTerm(term string) (result templateTerm, err error) {
+	// TODO(djd): Remove "*" suffix parsing once we check that no APIs have
+	// mistakenly used that attribute.
+	if strings.HasSuffix(term, "*") {
+		result.explode = true
+		term = term[:len(term)-1]
+	}
+	split := strings.Split(term, ":")
+	if len(split) == 1 {
+		result.name = term
+	} else if len(split) == 2 {
+		result.name = split[0]
+		var parsed int64
+		parsed, err = strconv.ParseInt(split[1], 10, 0)
+		result.truncate = int(parsed)
+	} else {
+		err = errors.New("multiple colons in same term")
+	}
+	if !validname.MatchString(result.name) {
+		err = errors.New("not a valid name: " + result.name)
+	}
+	if result.explode && result.truncate > 0 {
+		err = errors.New("both explode and prefix modifiers on same term")
+	}
+	return result, err
+}
+
+// Expand expands a URI template with a set of values to produce the
+// resultant URI. Two forms of the result are returned: one with all the
+// elements escaped, and one with the elements unescaped.
+func (t *uriTemplate) Expand(values map[string]string) (escaped, unescaped string) {
+	var w pairWriter
+	for _, p := range t.parts {
+		p.expand(&w, values)
+	}
+	return w.Escaped(), w.Unescaped()
+}
+
+func (tp *templatePart) expand(w *pairWriter, values map[string]string) {
+	if len(tp.raw) > 0 {
+		w.Write(tp.raw)
+		return
+	}
+	var first = true
+	for _, term := range tp.terms {
+		value, exists := values[term.name]
+		if !exists {
+			continue
+		}
+		if first {
+			w.Write(tp.first)
+			first = false
+		} else {
+			w.Write(tp.sep)
+		}
+		tp.expandString(w, term, value)
+	}
+}
+
+func (tp *templatePart) expandName(w *pairWriter, name string, empty bool) {
+	if tp.named {
+		w.Write(name)
+		if empty {
+			w.Write(tp.ifemp)
+		} else {
+			w.Write("=")
+		}
+	}
+}
+
+func (tp *templatePart) expandString(w *pairWriter, t templateTerm, s string) {
+	if len(s) > t.truncate && t.truncate > 0 {
+		s = s[:t.truncate]
+	}
+	tp.expandName(w, t.name, len(s) == 0)
+	w.Escape(s, tp.allowReserved)
+}

vendor/google.golang.org/api/internal/third_party/uritemplates/utils.go

@@ -0,0 +1,17 @@
+// Copyright 2016 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 uritemplates
+
+// Expand parses then expands a URI template with a set of values to produce
+// the resultant URI. Two forms of the result are returned: one with all the
+// elements escaped, and one with the elements unescaped.
+func Expand(path string, values map[string]string) (escaped, unescaped string, err error) {
+	template, err := parse(path)
+	if err != nil {
+		return "", "", err
+	}
+	escaped, unescaped = template.Expand(values)
+	return escaped, unescaped, nil
+}

vendor/google.golang.org/api/internal/version.go

@@ -0,0 +1,8 @@
+// Copyright 2022 Google LLC. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package internal
+
+// Version is the current tagged release of the library.
+const Version = "0.186.0"