Go 在 Cloud Run 中找不到默认凭据

我正在编写一个用Postgres方言与Cloud Spanner对话的程序.我的应用程序是一台GIN服务器，并且我正在使用pgAdapter进行连接，如this doc中所述.

My application runs fine locally. But when I deploy it to cloud run, I get the following log.

误差主要来自StartPGAdapterWithCredentials函数.

func StartPGAdapter(ctx context.Context, project, instance string) (port int, cleanup func(), err error) {
    credentials, err := google.FindDefaultCredentials(ctx)
    fmt.Println("credentials " + (credentials.ProjectID) + "json " + utils.ToString(credentials.JSON) + "ts " + utils.ToString(credentials.TokenSource))
    if err != nil {
        return 0, func() {}, err
    }
    return StartPGAdapterWithCredentials(ctx, project, instance, credentials)
}
func StartPGAdapterWithCredentials(ctx context.Context, project, instance string, credentials *google.Credentials) (port int, cleanup func(), err error) {
    if credentials == nil {
        return 0, func() {}, fmt.Errorf("credentials cannot be nil")
    }
    if credentials.JSON == nil || len(credentials.JSON) == 0 {
        return 0, func() {}, fmt.Errorf("only JSON based credentials are supported")
    }
    credentialsFile, err := os.CreateTemp(os.TempDir(), "pgadapter-credentials")
    if err != nil {
        return 0, func() {}, err
    }

在我的本地系统上，设置了GOOGLE_APPLICATION_CREDENTIALS，因此它能够获得凭据.然而，这在云运行中是行不通的.

我如何让它在云运行中运行？

附加信息:按照示例呈现here.