HealthCheckPlus.Abstractions 4.0.0

HealthCheckPlus.Abstractions

Abstractions of HealthCheckPlus - the shared contract between the main package and your own code.

This package holds only the types you need to read HealthCheckPlus state and write your own IHealthCheckPublisher - without depending on ASP.NET Core or the main HealthCheckPlus package's registration/middleware surface. Reach for it from a class library, a background worker, or any project that consumes health state but doesn't itself register or serve health checks.

If you're looking for AddHealthChecksPlus, UseHealthChecksPlus, AddBackgroundPolicy, or the response-writer templates, those live in the main HealthCheckPlus package instead - installing it already brings this one in as a dependency.

Table of Contents

• Installing
• What's in this package
• Usage
• Documentation
• Changelog
• Code of Conduct
• Contributing
• License

Installing

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Install-Package HealthCheckPlus.Abstractions [-pre]

dotnet add package HealthCheckPlus.Abstractions [--prerelease]

Note: [-pre]/[--prerelease] usage for pre-release versions

What's in this package

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• IStateHealthChecksPlus - read cached check results and named aggregates (Status, StatusResult, TryGetHealthy/TryGetNotHealthy/TryGetDegraded/TryGetUnhealthy, ConvertToPlus), or force a manual override (SwitchToUnhealthy/SwitchToDegraded). Resolve it from DI in any project that also references the main HealthCheckPlus package, which registers the implementation.
• IDataHealthPlus - one check's last result (Name, LastResult, Duration, DateRef, Origin), the shape ConvertToPlus returns.
• HealthCheckTrigger - what triggered a result (UrlRequest, Background, SwitchTo, None, Default).
• IHealthCheckPlusPublisher - implement this (instead of the native IHealthCheckPublisher) to add an optional PublisherCondition the background service checks before invoking your publisher.
• HealthReportExtensions - convenience extensions on the native HealthReport (StatusResult, TryGetHealthy/TryGetNotHealthy/TryGetDegraded/TryGetUnhealthy) for code that only ever sees a plain HealthReport (e.g. inside an IHealthCheckPublisher), without needing IStateHealthChecksPlus at all.

Usage

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Reading state from anywhere IStateHealthChecksPlus can be resolved (requires the main HealthCheckPlus package to be registered somewhere in the same host):

public class SomeService(IStateHealthChecksPlus state)
{
    public void Report()
    {
        var overall = state.Status();               // default aggregate
        var redis = state.StatusResult("MyRedis");   // one check's last HealthCheckResult

        if (state.TryGetUnhealthy(out var unhealthy))
        {
            foreach (var (name, result) in unhealthy)
            {
                // ...
            }
        }
    }
}

Writing a publisher with its own opt-in condition:

public class MyPublisher : IHealthCheckPlusPublisher
{
    public Func<HealthReport, bool>? PublisherCondition { get; set; } = report => report.Status != HealthStatus.Healthy;

    public Task PublishAsync(HealthReport report, CancellationToken cancellationToken)
    {
        if (report.TryGetUnhealthy(out var unhealthy))
        {
            // ...
        }
        return Task.CompletedTask;
    }
}

Documentation

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• Points of attention - what to know before you build on HealthCheckPlus, in plain language. Start here.
• Architecture - how HealthCheckPlus is put together internally, for maintainers and contributors.
• Operational runbook - how to read a health check response and diagnose common problems, for operators.
• API reference - generated from the XML doc comments.

Changelog

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See CHANGELOG.md for the version history (shared with the main package - both are versioned and released together).

Code of Conduct

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This project has adopted the code of conduct defined by the Contributor Covenant to clarify expected behavior in our community. For more information see the Code of Conduct.

Contributing

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See the Contributing guide for developer documentation.

License

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Copyright 2023 @ Fernando Cerqueira