Grpc.Core.RpcException StatusCode Unavailable Channel 处于状态 TRANSIENT_FAILURE

Question

I am using Google Vision API to get associated labels for an image.

 var client = ImageAnnotatorClient.Create();
 var image = Image.FromFile(@"C:\Users\Scorpio\Desktop\th.jpg");
 var response = client.DetectLabels(image); // error
 foreach (var annotation in response)
 {
     if (annotation.Description != null)
           Console.WriteLine(annotation.Description);
 }

Any idea how can we resolve this issue? I tried using very common images like country flags but still it gives error.

Answer 1

I just replicate this scenario by using your code and it ran successfully. Based on this, it is possible that this issue was related to a temporary and transient error from the service side, as mentioned in the error message; however, I recommend you to verify you are adding the correct libraries.

Below is the code I used to perform the testing which includes the authentication process:

using Google.Cloud.Vision.V1;
using System;
using Grpc.Auth;
using Google.Apis.Auth.OAuth2;

namespace VisionDemo
{
    class Program
    {   
        static void Main(string[] args)
        {
            //Authenticate to the service by using Service Account
            var credential = GoogleCredential.FromFile(@"<CREDENTIALS_JSON_FILE_PATH>").CreateScoped(ImageAnnotatorClient.DefaultScopes);
            var channel = new Grpc.Core.Channel(ImageAnnotatorClient.DefaultEndpoint.ToString(), credential.ToChannelCredentials());
            // Instantiates a client
            var client = ImageAnnotatorClient.Create(channel);
            var image = Image.FromFile(@"<IMAGE_PATH>");
            var response = client.DetectLabels(image); // error
            foreach (var annotation in response)
            {
                if (annotation.Description != null)
                    Console.WriteLine(annotation.Description);
            }

        }
    }
}

In case you continue having this issue, you could take a look the Issue Tracker tool that you can use to raise a Vision API in order to verify this scenario with the Google Technical Support Team and check if this behavior can being generated with an issue on your project.

Answer 2

 Environment.SetEnvironmentVariable("GOOGLE_APPLICATION_CREDENTIALS", @"C:\Users\#YOURUSER#\source\repos\PdfToImage\credentials.json");

Answer 3

I bumped into the same issue. Found the root cause and fixed it.

Issue is due to Nuget package: Grpc.Core.Api This package got updated to version: 2.25.0, whereas Grpc.Core is blocked at version 1.22.1 due to Google.Api.Gax.Grpc 2.10.0

Nothing stops you from updating Grpc.Core.Api to 2.25.0 version and then face the weird issue - client.Detect... methods not returning success or error, nothing (I didnt wait for 20 mins).

Solution Grpc.Core.Api - bring the version number back to 1.22.1

Hope that helps!