OrleansHealthCheck.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Orleans.AspNetCore.Demo.Grains;

namespace Orleans.AspNetCore.Demo
{
    public class OrleansHealthCheck : IHealthCheck
    {
        private readonly IClusterClient _clusterClient;
        
        public OrleansHealthCheck(IClusterClient clusterClient)
        {
            _clusterClient = clusterClient;
        }

        public async Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
        {
            if (_clusterClient.IsInitialized == false)
            {
                return HealthCheckResult.Healthy("Initializing");
            }
            
            try
            {
                return await _clusterClient.GetGrain<IHealthCheckGrain>(Guid.Empty).IsHealthy() 
                    ? HealthCheckResult.Healthy() 
                    : HealthCheckResult.Unhealthy();
            }
            catch (Exception ex)
            {
                return HealthCheckResult.Unhealthy("HealthCheckGrain failed.", ex);
            }
        }
    }

    public static class OrleansHealthCheckBuilderExtension
    {
        private const string HealthCheckName = "OrleansHealthCheck";

        public static IHealthChecksBuilder AddOrleansHealthCheck(this IHealthChecksBuilder builder)
        {
            return builder.Add(new HealthCheckRegistration(HealthCheckName, sp => new OrleansHealthCheck( sp.GetRequiredService<IClusterClient>()), HealthStatus.Unhealthy, new string[0]));
        }
    }
}