How to add global exception handler for gRPC services in ASP.NET Core?

Question

I'm writing gRPC services using ASP.NET Core using GRPC.ASPNETCore.

I've tried to add an Exception Filter for gRPC methods like this

services.AddMvc(options =>
{
    options.Filters.Add(typeof(BaseExceptionFilter));
});

or using the UseExceptionHandler extension method like this

app.UseExceptionHandler(configure =>
{
    configure.Run(async e =>
    {
        Console.WriteLine("Exception test code");
    });
});

But both of them are not working (not intercepting code).

Is it possible to add global exception handler for gRPC services in ASP.NET Core?

I don't want to write try-catch code wrapper for each method I want to call.

You should be able to use a gRPC server-side interceptor (which is a gRPC concept) - that can catch an handle any exceptions being thrown by your server-side handler methods. See e.g. https://github.com/grpc/grpc-dotnet/blob/098893e777049586b6f27d19bf255d18069593a2/examples/Logger/Server/Startup.cs#L33 — Jan Tattermusch, Nov 28 '19 at 16:38
@Jan Tattermusch, yes, I've done this both on the client and server side. I hoped that it's possible to use ASP.NET Core exception nadling mechanism because it's easier to implement, but it's really no way. — Dmitriy, Nov 29 '19 at 08:03
have you found any solution for this? I can see the log message in the console app, but can't find a way to write it to the disk — Thiago Custodio, Mar 20 '20 at 16:10

score 16 · Accepted Answer · answered Sep 10 '20 at 08:43

Add custom interceptor in Startup

services.AddGrpc(options =>
{
    {
        options.Interceptors.Add<ServerLoggerInterceptor>();
        options.EnableDetailedErrors = true;
    }
});

Create custom class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Grpc.Core;
using Grpc.Core.Interceptors;
using Microsoft.Extensions.Logging;

namespace Systemx.WebService.Services
{
    public class ServerLoggerInterceptor : Interceptor
    {
        private readonly ILogger<ServerLoggerInterceptor> _logger;

        public ServerLoggerInterceptor(ILogger<ServerLoggerInterceptor> logger)
        {
            _logger = logger;
        }

        public override async Task<TResponse> UnaryServerHandler<TRequest, TResponse>(
            TRequest request,
            ServerCallContext context,
            UnaryServerMethod<TRequest, TResponse> continuation)
        {
            //LogCall<TRequest, TResponse>(MethodType.Unary, context);

            try
            {
                return await continuation(request, context);
            }
            catch (Exception ex)
            {
                // Note: The gRPC framework also logs exceptions thrown by handlers to .NET Core logging.
                _logger.LogError(ex, $"Error thrown by {context.Method}.");                

                throw;
            }
        }
       
    }
}

How to add global exception handler for gRPC services in ASP.NET Core?

Is it possible to add global exception handler for gRPC services in ASP.NET Core?

1 Answers1