|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Microsoft.Extensions.Options;
namespace HealthChecksSample;
// This is an example of a custom health check that implements IHealthCheck.
//
// This example also shows a technique for authoring a health check that needs to be registered
// with additional configuration data. This technique works via named options, and is useful
// for authoring health checks that can be disctributed as libraries.
public static class GCInfoHealthCheckBuilderExtensions
{
public static IHealthChecksBuilder AddGCInfoCheck(
this IHealthChecksBuilder builder,
string name,
HealthStatus? failureStatus = null,
IEnumerable<string> tags = null,
long? thresholdInBytes = null)
{
// Register a check of type GCInfo
builder.AddCheck<GCInfoHealthCheck>(name, failureStatus ?? HealthStatus.Degraded, tags);
// Configure named options to pass the threshold into the check.
if (thresholdInBytes.HasValue)
{
builder.Services.Configure<GCInfoOptions>(name, options =>
{
options.Threshold = thresholdInBytes.Value;
});
}
return builder;
}
}
public class GCInfoHealthCheck : IHealthCheck
{
private readonly IOptionsMonitor<GCInfoOptions> _options;
public GCInfoHealthCheck(IOptionsMonitor<GCInfoOptions> options)
{
_options = options;
}
public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default(CancellationToken))
{
var options = _options.Get(context.Registration.Name);
// This example will report degraded status if the application is using
// more than the configured amount of memory (1gb by default).
//
// Additionally we include some GC info in the reported diagnostics.
var allocated = GC.GetTotalMemory(forceFullCollection: false);
var data = new Dictionary<string, object>()
{
{ "Allocated", allocated },
{ "Gen0Collections", GC.CollectionCount(0) },
{ "Gen1Collections", GC.CollectionCount(1) },
{ "Gen2Collections", GC.CollectionCount(2) },
};
// Report failure if the allocated memory is >= the threshold.
//
// Using context.Registration.FailureStatus means that the application developer can configure
// how they want failures to appear.
var result = allocated >= options.Threshold ? context.Registration.FailureStatus : HealthStatus.Healthy;
return Task.FromResult(new HealthCheckResult(
result,
description: "reports degraded status if allocated bytes >= 1gb",
data: data));
}
}
public class GCInfoOptions
{
// The failure threshold (in bytes)
public long Threshold { get; set; } = 1024L * 1024L * 1024L;
}
|