JobHealthz 0.1.1

.NET Standard 2.0
dotnet add package JobHealthz --version 0.1.1
NuGet\Install-Package JobHealthz -Version 0.1.1
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="JobHealthz" Version="0.1.1" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add JobHealthz --version 0.1.1
#r "nuget: JobHealthz, 0.1.1"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install JobHealthz as a Cake Addin
#addin nuget:?package=JobHealthz&version=0.1.1

// Install JobHealthz as a Cake Tool
#tool nuget:?package=JobHealthz&version=0.1.1


A simple library for adding a health check endpoint to your jobs


Background jobs either run continuously or on a schedule. Either way, they can sometimes end up in a state where they are not actually doing anything. For example, a job that runs on a schedule to query a database for work and then acts on that work may get stuck somewhere in a loop. When this happens you want that job to be killed and restarted rather than just continuing on for hours doing nothing.

Orchestrators (like Kubernetes) allow you to perform periodical health checks on your applications using probes. If the health check fails, the application can be easily killed and rescheduled. The /heathz endpoint is a common practice for such health checks.

Getting started

1 - Install JobHealthz using NuGet -

2 - In your application's startup, intialize Healthz and call Start with a callback for evaluating the health of the running process - e.g.

new Healthz()
    .Start(() => return new HealthzResult {
        Status = HealthzStatus.Ok,
        Message = "Nothing to see here..."

How does it work?

This library uses Microsoft.AspNetCore.Server.Kestrel to expose a single HTTP endpoint. When you start it, it will configure the web server using the default ASP.NET Core URLs and map the /healthz endpoint to a health check. This is what you'll see on your console:

Health checks listening on http://localhost:5000,https://localhost:5001 at /healthz.

You can change the base URL by setting the ASPNETCORE_URLS environment variable - e.g. ASPNETCORE_URLS=http://localhost dotnet run.

When the /healthz endpoint is called, the callback provided will be invoked and the result translated to a HTTP response - e.g.

$ curl localhost:5000/healthz -v
*   Trying ::1...
* Connected to localhost (::1) port 5000 (#0)
> GET /healthz HTTP/1.1
> Host: localhost:5000
> User-Agent: curl/7.54.0
> Accept: */*
< HTTP/1.1 200 OK
< Date: Thu, 16 Aug 2018 11:08:50 GMT
< Server: Kestrel
< Transfer-Encoding: chunked
* Connection #0 to host localhost left intact
Nothing to see here...

Logging health checks

To get more visibility into the health checks, you can use Microsoft's libraries for DI and Logging to initialise Healthz with logging enabled.

var serviceProvider = new ServiceCollection()
    .AddLogging(l => l.AddConsole())

    .Start(() => return new HealthzResult {
            Status = HealthzStatus.Ok,
            Message = "Nothing to see here..."

Using IHealthCheck

Another way of specifying health checks is to implement the IHealthCheck interface and call Healthz.Start with it. There is also an implementation of this in the library called LastCheckpointHealthCheck which keeps track of the last time you call Checkpoint() and will return an Ok response while it is within a threshold. E.g.

var check = new LastCheckpointHealthCheck(TimeSpan.FromMinutes(1));
new Healthz.Start(check);
while (true) {
    // do work...

If it takes longer than 1 minute between calls to Checkpoint() in the above snippet, the endpoint will return a Fail response.

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Additional computed target framework(s)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

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Version Downloads Last updated
0.1.1 911 8/17/2018
0.1.0 739 8/16/2018