Hangfire integration in BackgroundJobs

[xorinzor]

Initially I used the native implementation of Backgrounds Jobs which was working perfectly fine.

Now I'd like to support clustering, therefor I followed this documentation to integrate Hangfire https://docs.abp.io/en/abp/latest/Background-Jobs-Hangfire

Additionally I added Hangfire.SqlServer 1.7.29 to my csproj.

However, my jobs are still being added to the native AbpBackgroundJobs table and not being picked up or registered in Hangfire.

I tried removing all other AbpBackgroundJob things, but that did not make a difference.
Additionally I checked all namespaces.

Is there an example project somewhere to compare to? I think something in the documentation is missing, but I don't know what.

EDIT:

When I add this line to my Module in ConfigureServices

context.Services.Replace(ServiceDescriptor.Transient<IBackgroundJobManager, HangfireBackgroundJobManager>());

While having both of these defined in the Module too

[DependsOn(
    typeof(AbpBackgroundJobsModule),
    typeof(AbpBackgroundJobsHangfireModule)
)]

It's throwing the error

Volo.Abp.AbpException: Undefined background job for the job args type: My.Project.Jobs.JobNameArgs
   at Volo.Abp.BackgroundJobs.Hangfire.HangfireBackgroundJobManager.GetQueueName(Type argsType)
   at lambda_method3698(Closure, Object, List`1)
   at Hangfire.Common.ExpressionUtil.CachedExpressionCompiler.Compiler`2.<>c__DisplayClass7_1.<CompileFromFingerprint>b__1(TIn model)
   at Hangfire.Common.CachedExpressionCompiler.Evaluate(Expression arg)
   at Hangfire.Common.Job.GetExpressionValue(Expression expression)
   at System.Linq.Enumerable.SelectIListIterator`2.ToArray()
   at Hangfire.Common.Job.GetExpressionValues(IEnumerable`1 expressions)
   at Hangfire.Common.Job.FromExpression(LambdaExpression methodCall, Type explicitType)
   at Hangfire.Common.Job.FromExpression[TType](Expression`1 methodCall)
   at Hangfire.BackgroundJobClientExtensions.Create[T](IBackgroundJobClient client, Expression`1 methodCall, IState state)
   at Hangfire.BackgroundJobClientExtensions.Enqueue[T](IBackgroundJobClient client, Expression`1 methodCall)
   at Hangfire.BackgroundJob.Enqueue[T](Expression`1 methodCall)
   at Volo.Abp.BackgroundJobs.Hangfire.HangfireBackgroundJobManager.EnqueueAsync[TArgs](TArgs args, BackgroundJobPriority priority, Nullable`1 delay)

If I only leave this:

[DependsOn(
    typeof(AbpBackgroundJobsHangfireModule)
)]

The error disappears, but it still adds any jobs to the native AbpBackgroundJob table instead of adding them to hangfire.

EDIT 2:
I have my JobArgs classes in the domain project, whereas the Job classes are in the Worker project. I'm Enqueing the jobs from the Web project, which doesn't use the Worker project (assembly).

Could that be related? Why does it work for the native non-hangfire backgroundjob implementation?

[xorinzor]

I think I found the problem.

The native BackgroundJobManger doesn't actually lookup the Job Type whereas the Hangfire HangfireBackgroundJobManager does.

Native:
https://github.com/abpframework/abp/blob/dev/framework/src/Volo.Abp.BackgroundJobs/Volo/Abp/BackgroundJobs/DefaultBackgroundJobManager.cs#L32

Hangfire:
https://github.com/abpframework/abp/blob/dev/framework/src/Volo.Abp.BackgroundJobs.HangFire/Volo/Abp/BackgroundJobs/Hangfire/HangfireBackgroundJobManager.cs#L21

Would it be possible for Hangfire to queue a job without looking up the job, or without having the Job class registered? It doesn't really make sense for the Web project to have access to the Job class, since all it needs is the JobArg class.

[xorinzor]

Overriding the GetQueueName method from HangfireBackgroundJobManager using the code below got me 1 step further. It now enqueues the job in Hangfire (using the native BackgroundJobname attribute as defined at the Job Args instead of the Queue attribute in the Job itself.

public class CustomHangfireBackgroundJobManager : HangfireBackgroundJobManager
{
    public CustomHangfireBackgroundJobManager(IOptions<AbpBackgroundJobOptions> options) : base(options)
    {
    }
    
    protected override string GetQueueName(Type argsType)
    {
        return BackgroundJobNameAttribute.GetName(argsType);
    }
}

Make sure to also replace this class in DI

context.Services.Replace(ServiceDescriptor.Transient<IBackgroundJobManager, CustomHangfireBackgroundJobManager>());