// DialGRPC returns a GRPC connection for use communicating with a Google cloud
// service, configured with the given ClientOptions.
func DialGRPC(ctx context.Context, opt ...cloud.ClientOption) (*grpc.ClientConn, error) {
var o opts.DialOpt
for _, opt := range opt {
opt.Resolve(&o)
}
if o.HTTPClient != nil {
return nil, errors.New("unsupported HTTP base transport specified")
}
if o.GRPCClient != nil {
return o.GRPCClient, nil
}
if o.TokenSource == nil {
var err error
o.TokenSource, err = google.DefaultTokenSource(ctx, o.Scopes...)
if err != nil {
return nil, fmt.Errorf("google.DefaultTokenSource: %v", err)
}
}
grpcOpts := []grpc.DialOption{
grpc.WithPerRPCCredentials(oauth.TokenSource{o.TokenSource}),
grpc.WithTransportCredentials(credentials.NewClientTLSFromCert(nil, "")),
}
grpcOpts = append(grpcOpts, o.GRPCDialOpts...)
if o.UserAgent != "" {
grpcOpts = append(grpcOpts, grpc.WithUserAgent(o.UserAgent))
}
return grpc.Dial(o.Endpoint, grpcOpts...)
}
// NewApplicationDefault returns "Application Default Credentials". For more
// detail, see https://developers.google.com/accounts/docs/application-default-credentials.
func NewApplicationDefault(ctx context.Context, scope ...string) (credentials.Credentials, error) {
t, err := google.DefaultTokenSource(ctx, scope...)
if err != nil {
return nil, err
}
return TokenSource{t}, nil
}
// NewHTTPClient returns an HTTP client for use communicating with a Google cloud
// service, configured with the given ClientOptions. It also returns the endpoint
// for the service as specified in the options.
func NewHTTPClient(ctx context.Context, opt ...cloud.ClientOption) (*http.Client, string, error) {
var o opts.DialOpt
for _, opt := range opt {
opt.Resolve(&o)
}
if o.GRPCClient != nil {
return nil, "", errors.New("unsupported GRPC base transport specified")
}
// TODO(djd): Wrap all http.Clients with appropriate internal version to add
// UserAgent header and prepend correct endpoint.
if o.HTTPClient != nil {
return o.HTTPClient, o.Endpoint, nil
}
if o.TokenSource == nil {
var err error
o.TokenSource, err = google.DefaultTokenSource(ctx, o.Scopes...)
if err != nil {
return nil, "", fmt.Errorf("google.DefaultTokenSource: %v", err)
}
}
return oauth2.NewClient(ctx, o.TokenSource), o.Endpoint, nil
}