Health actuator cannot handle health checks depending on scoped services

[christianerbsmehl]

Describe the bug

I've recently updated one of our projects to Steeltoe 4.0. When calling the /actuator/health endpoint, I can see that the health check of my EF DBContext is throwing an exception:

   "MyDbContext": {
      "status": "UNKNOWN",
      "details": {
        "exception": "Cannot resolve scoped service 'MyApi.MyDbContext' from root provider."
      }
    },

I found out that since Steeltoe 4.0, all health actuator services are registered as singleton and the IHealthCheck implementations which depend on scoped services cannot be executed. I think the HealthAggregator should create an IServiceScope before executing the health checks to solve this issue.

Since I'm using the .AddDbContextCheck<TContext>() extension method of Microsoft.Extensions.Diagnostics.HealthChecks.EntityFrameworkCore I have no option to create the IServiceScope by myself. Also, DbContext DI registrations should always be scoped so I cannot change kind of the registration here.

Steps to reproduce

Steps to reproduce the behavior:

1. Create and register a scoped service builder.Services.AddScoped<MyScopedService>()
2. Create an implementation if an IHealthCheck that depends on the scoped service
3. Register the health actuator
4. Register the health check using builder.Services.Addhealth(builder.Configuration).AddCheck<MyScopedHealthCheck>("ScopedCheck")
5. Call the /actuator/health endpoint
6. Observe the 'Cannot resolve scoped service 'MyScopedService' from root provider.' message

Expected behavior

The health check should execute without errors.

Environment (please complete the following information):

• Steeltoe Version: 4.0.0
• Platform: Windows DEV machine, Cloud Foundry
• OS: Win 11, Linux
• .NET Version 9.0

Screenshots

If applicable, add screenshots to help explain your problem.

Additional context or links

Add any other context about the problem here.

[christianerbsmehl]

Additionaly, I found out that the xml doc lies about how the IHealthContributors are being registered: https://github.com/SteeltoeOSS/Steeltoe/blob/main/src/Management/src/Endpoint/Actuators/Health/EndpointServiceCollectionExtensions.cs#L79

(scoped instead of singleton)

[bart-vmware]

@christianerbsmehl Thanks for reporting this. I'm working on a fix. Until that's available, the following workaround can be used:

builder.Services.AddSingleton<IHealthAggregator, CustomHealthAggregator>();
builder.Services.AddHealthActuator();

internal sealed class CustomHealthAggregator : IHealthAggregator
{
    private readonly IHealthAggregator _innerAggregator;

    public CustomHealthAggregator()
    {
        Type innerType = typeof(IHealthAggregator).Assembly.GetType(
            "Steeltoe.Common.HealthChecks.HealthAggregator", true)!;
        _innerAggregator = (IHealthAggregator)Activator.CreateInstance(innerType)!;
    }

    public async Task<HealthCheckResult> AggregateAsync(ICollection<IHealthContributor> contributors,
        ICollection<HealthCheckRegistration> healthCheckRegistrations, IServiceProvider serviceProvider,
        CancellationToken cancellationToken)
    {
        await using AsyncServiceScope scope = serviceProvider.CreateAsyncScope();
        return await _innerAggregator.AggregateAsync(contributors, healthCheckRegistrations,
            scope.ServiceProvider, cancellationToken);
    }
}

[christianerbsmehl]

Thanks for the workaround. I'll take this as a temporary fix and hope the update will arrive soon. Happy holidays!