File: Program.cs
Web Access
Project: src\playground\HealthChecks\HealthChecksSandbox.AppHost\HealthChecksSandbox.AppHost.csproj (HealthChecksSandbox.AppHost)
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Aspire.Hosting.Lifecycle;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Diagnostics.HealthChecks;
 
var builder = DistributedApplication.CreateBuilder(args);
 
builder.Services.TryAddLifecycleHook<TestResourceLifecycleHook>();
 
AddTestResource("healthy", HealthStatus.Healthy, "I'm fine, thanks for asking.");
AddTestResource("unhealthy", HealthStatus.Unhealthy, "I can't do that, Dave.", exceptionMessage: "Feeling unhealthy.");
AddTestResource("degraded", HealthStatus.Degraded, "Had better days.", exceptionMessage: "Feeling degraded.");
 
#if !SKIP_DASHBOARD_REFERENCE
// This project is only added in playground projects to support development/debugging
// of the dashboard. It is not required in end developer code. Comment out this code
// or build with `/p:SkipDashboardReference=true`, to test end developer
// dashboard launch experience, Refer to Directory.Build.props for the path to
// the dashboard binary (defaults to the Aspire.Dashboard bin output in the
// artifacts dir).
builder.AddProject<Projects.Aspire_Dashboard>(KnownResourceNames.AspireDashboard);
#endif
 
builder.Build().Run();
 
void AddTestResource(string name, HealthStatus status, string? description = null, string? exceptionMessage = null)
{
    var hasHealthyAfterFirstRunCheckRun = false;
    builder.Services.AddHealthChecks()
                    .AddCheck(
                        $"{name}_check",
                        () => new HealthCheckResult(status, description, new InvalidOperationException(exceptionMessage))
                        )
                        .AddCheck($"{name}_resource_healthy_after_first_run_check", () =>
                        {
                            if (!hasHealthyAfterFirstRunCheckRun)
                            {
                                hasHealthyAfterFirstRunCheckRun = true;
                                return new HealthCheckResult(HealthStatus.Unhealthy, "Initial failure state.");
                            }
 
                            return new HealthCheckResult(HealthStatus.Healthy, "Healthy beginning second health check run.");
                        });
 
    builder
        .AddResource(new TestResource(name))
        .WithHealthCheck($"{name}_check")
        .WithHealthCheck($"{name}_resource_healthy_after_first_run_check")
        .WithInitialState(new()
        {
            ResourceType = "Test Resource",
            State = "Starting",
            Properties = [],
        })
        .ExcludeFromManifest();
    return;
}
 
internal sealed class TestResource(string name) : Resource(name);
 
internal sealed class TestResourceLifecycleHook(ResourceNotificationService notificationService) : IDistributedApplicationLifecycleHook
{
    public Task BeforeStartAsync(DistributedApplicationModel appModel, CancellationToken cancellationToken)
    {
        foreach (var resource in appModel.Resources.OfType<TestResource>())
        {
            Task.Run(
                async () =>
                {
                    await Task.Delay(TimeSpan.FromSeconds(10));
 
                    await notificationService.PublishUpdateAsync(
                        resource,
                        state => state with { State = new("Running", "success") });
                },
                cancellationToken);
        }
 
        return Task.CompletedTask;
    }
}