Hangfire integration of Correlate to add correlation id support to Hangfire background/scheduled jobs.

Install Hangfire.Correlate via the Nuget package manager or dotnet cli.

dotnet add package Hangfire.Correlate

Hangfire.Correlate		Correlate integration with Hangfire.

The Correlate framework provides an ambient correlation context scope, that makes it easy to track a Correlation ID passing through (micro)services.

This library specifically provides a job filter for Hangfire and ensures each job is performed (run) in its own correlation context provided by Correlate.

Whenever a job is enqueued in an existing correlation context, the current correlation id will be attached to the job as a job parameter. If no correlation context is available when the job is enqueued, no parameter is added.

When the job is 'performed' (in Hangfire terms), the job parameter (for correlation id) that was added during job creation will be used to create a new correlation context, thus reviving the correlation context. This means that even in distributed scenarios, the same correlation id is used to process the job.

If no correlation id was stored with the job, yet also to remain backwards compatible with existing jobs (prior to Correlate integration), the job id will be used instead.

A continuation job will inherit the correlation id from the parent job, unless explicitly inside an active correlation context.

Configure Hangfire to use Correlate.

Use the Hangfire built-in configuration extensions to enable Correlate.

ILoggerFactory loggerFactory = new LoggerFactory();
loggerFactory.AddConsole();

GlobalConfiguration.Configuration
    .UseCorrelate(loggerFactory)
    .(...);

Alternatively (but recommended), use IServiceProvider to configure Hangfire with Correlate.

Add package dependencies:

• Correlate.DependencyInjection

services
    .AddLogging(logging => logging.AddConsole())
    .AddCorrelate()
    .AddHangfire((serviceProvider, config) => config
        .UseCorrelate(serviceProvider)
        .(...)
    );

This example illustrates how jobs that are enqueued, inherit the Correlation ID from the ambient correlation context if inside one.

public class MyService
{
    private IAsyncCorrelationManager _correlationManager;
    private IBackgroundJobClient _client;

    public MyService(IAsyncCorrelationManager correlationManager, IBackgroundJobClient client)
    {
        _correlationManager = _correlationManager;
        _client = client;
    }

    public async Task DoWork()
    {
        // Without ambient correlation context, the job id will be used.
        _client.Enqueue(() => Thread.Sleep(1000));

        // Perform work in new correlation context.
        string parentJobId = await _correlationManager.CorrelateAsync(async () =>
        {
            // This job be executed with the Correlation ID from
            // the ambient correlation context which is automatically
            // generated.
            _client.Enqueue(() => Thread.Sleep(1000));

            // Do stuff.
            await ..

            // This job will be also be executed with the same Correlation ID.
            return _client.Enqueue<MyJob>(myJob => myJob.CallApiAsync());
        });

          // This job will be also be executed with the same Correlation ID
          // as which MyJob.CallApiAsync() was executed, even though it is
          // outside the ambient correlation context, because it is a 
          // continuation and we used its job id to enqueue it.
        _client.ContinueJobWith(parentJobId, () => Thread.Sleep(1000));
    }
}

Note: when using Correlate integration for ASP.NET Core, each request is already scoped to a correlation context, and so there is no need to wrap the enqueueing of jobs with IAsyncCorrelationManager/ICorrelationManager.

See Correlate documentation for further integration with ASP.NET Core, IHttpClientFactory and for other extensions/libraries.

• .NET Standard 2.0
• .NET Standard 1.3
• .NET Framework 4.6

• Visual Studio 2017
• .NET Core 2.2/2.1 SDK
• .NET 4.6 targetting pack

PR's are welcome. Please rebase before submitting, provide test coverage, and ensure the AppVeyor build passes. I will not consider PR's otherwise.

• skwas (author/maintainer)