如何验证用于Dialogflow集成的Google凭据

Question

I want to integrate my C# system with Google Dialogflow. So I'm trying to use the code Mr. Jon showed me over here:

How to import a dialogflow zip using an API

But I'm getting this problem:

The Application Default Credentials are not available. They are available if running in Google Compute Engine. Otherwise, the environment variable GOOGLE_APPLICATION_CREDENTIALS must be defined pointing to a file defining the credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.

I've downloaded my Dialogflow Project Service Account Key JSON File. And I'm trying to use this code to Authenticate:

// Some APIs, like Storage, accept a credential in their Create() method.
// Explicitly use service account credentials by specifying the private key file.
GoogleCredential credential = GoogleCredential.FromFile(theServiceAccountJSONFilePath);
StorageClient storage = StorageClient.Create(credential);
// Make an authenticated API request.
PagedEnumerable<Buckets, Bucket> buckets = storage.ListBuckets(theProjectID);
foreach (Bucket bucket in buckets)
{
    Console.WriteLine(bucket.Name);
}
return null;

I got that code from this link: Setting Up Authentication for Server to Server Production Applications

Problem is that code runs into this problem for me:

dialogflow-ixksso@maintest-vskxxy.iam.gserviceaccount.com does not have storage.buckets.list access to project 160007643358.

I am on the free option on my 'Google Cloud Platform'. Maybe the free option doesn't allow authenticating in this way.

I don't have a lot of experience with this, so any advice would be appreciated.

Answer 1

As noted in comments, the simplest way in most cases is to specify the GOOGLE_APPLICATION_CREDENTIALS environment variable to refer to the JSON file.

If you need to load the credential some other way, you can use the client builder to specify credentials quite flexibly:

From an ICredential

ICredential credential = LoadCredentialFromSomewhere();
var client = new AgentsClientBuilder
{
    TokenAccessMethod = credential.GetAccessTokenForRequestAsync 
}.Build();

From a path to a JSON file

var client = new AgentsClientBuilder
{
    CredentialsPath = "/path/to/serviceaccount.json"
}.Build();

From JSON you already have as a string

string json = LoadJsonFromSomewhere();
var client = new AgentsClientBuilder
{
    JsonCredentials = json
}.Build();