[WIP] Dependency Injected HealthChecks #659
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- Add WithHealthCheck<T>() generic methods for DI-resolved health checks - Support both simple registration and template-based configuration - Implement DiResolvedHealthCheck<T> wrapper for lazy DI resolution
…ption' if the health check type is not registered
Aaronontheweb
added
the
health-checks
| /// </summary> | ||
| /// <exception cref="ArgumentNullException"></exception> | ||
| public IAkkaHealthCheck HealthCheck | ||
| public Func<IServiceProvider,IAkkaHealthCheck> Factory |
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Bit of a breaking change here - decided to use the Microsoft.Extensions.HealthCheck pattern here of passing in the IServiceProvider so we can resolve any CTOR dependencies a healthcheck might require. This addresses my comment on #658 (comment) but without requiring us to do any updates to Akka.DependencyInjection.
I prefer it this way because the health checks infrastructure is coupled to the IServiceCollection anyway - no point in having a separate abstraction.
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I also think the impact of this change should be minimal.
| /// <param name="timeout">An optional <see cref="TimeSpan"/> representing the timeout of the check.</param> | ||
| /// <exception cref="ArgumentNullException">Thrown if <see cref="name"/> is null.</exception> | ||
| /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative timeout other than <see cref="System.Threading.Timeout.InfiniteTimeSpan"/> is used.</exception> | ||
| internal AkkaHealthCheckRegistration(string name, Func<IServiceProvider, IAkkaHealthCheck> factory, HealthStatus? failureStatus, |
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CTOR overload which takes an Func<IServiceProvider, IAkkaHealthCheck> delegate . I don't see much value in making it public but I could be persuaded either way - the extension methods on the AkkaConfigurationBuilder use this for DI'd health check registrations.
| HealthChecks[registration.Name] = registration; | ||
| return this; | ||
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| static T GetServiceOrCreateInstance(IServiceProvider sp) => ActivatorUtilities.GetServiceOrCreateInstance<T>(sp); |
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This is the big time-saver - it uses the ActivatorUtilities from MSFT.EXT.DI to handle the IServiceProvider resolution / instantiation of CTOR arguments for us, so we're not having to write that code ourselves. This is the same thing that powers the DI'd Props in Akka.DependencyInjection.
| // func for lazily instantiating the health check registration | ||
| Func<IServiceProvider, IHealthCheck> adapter = provider => | ||
| new HealthCheckAdapter(registration.HealthCheck, provider.GetRequiredService<ActorSystem>()); | ||
| new HealthCheckAdapter(registration.Factory(provider), provider.GetRequiredService<ActorSystem>()); |
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Changed the health check adapter only slightly here - it's still a delayed instantiation until the health checks actually get invoked.
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I need to add a tiny bit of documentation for this |
3 participants
Changes
Supersedes #658
Checklist
For significant changes, please ensure that the following have been completed (delete if not relevant):