Hangfire - Prevent multiples of the same job being enqueued

Question

Scenario:

Job 1 is scheduled to run every 5 minutes, and takes ~1 minute to complete.

A lot of work piles up and Job 1 takes 15 minutes to run.

There are now three Job 1's being processed concurrently - I don't want this.

---

How do I prevent Job 1 being added to the queue again if it is already there?

Is there Hangfire setting, or do I need to poll job statuses manually?

Answer 1

You can use DisableConcurrentExecution attribute to prevent multiple executions of a method concurrently. Just put this attribute above your method -

[DisableConcurrentExecution(timeoutInSeconds: 10 * 60)]
public void Job1()
{
    // Metohd body
}

Answer 2

a bit late but i was using this class to prevent duplicate jobs to run concurrently

public class SkipConcurrentExecutionAttribute : JobFilterAttribute, IServerFilter, IElectStateFilter
{
    private readonly int _timeoutSeconds;
    private const string DistributedLock = "DistributedLock";

    public SkipConcurrentExecutionAttribute(int timeOutSeconds)
    {
        if (timeOutSeconds < 0) throw new ArgumentException("Timeout argument value should be greater that zero.");
        this._timeoutSeconds = timeOutSeconds;
    }

    public void OnPerformed(PerformedContext filterContext)
    {
        if (!filterContext.Items.ContainsKey(DistributedLock))
            throw new InvalidOperationException("Can not release a distributed lock: it was not acquired.");

        var distributedLock = (IDisposable)filterContext.Items[DistributedLock];
        distributedLock?.Dispose();
    }



    public void OnPerforming(PerformingContext filterContext)
    {
        filterContext.WriteLine("Job Started");

        var resource = String.Format(
                           "{0}.{1}",
                          filterContext.BackgroundJob.Job.Type.FullName,
                          filterContext.BackgroundJob.Job.Method.Name);

        var timeOut = TimeSpan.FromSeconds(_timeoutSeconds);

        filterContext.WriteLine($"Waiting for running jobs to complete. (timeout: { _timeoutSeconds })");

        try
        {
            var distributedLock = filterContext.Connection.AcquireDistributedLock(resource, timeOut);
            filterContext.Items[DistributedLock] = distributedLock;
        }
        catch (Exception ex)
        {
            filterContext.WriteLine(ex);
            filterContext.WriteLine("Another job is already running, aborted.");
            filterContext.Canceled = true; 
        }

    }

    public void OnStateElection(ElectStateContext context)
    {
        //if (context.CandidateState as FailedState != null)
        //{

        //}
    }
}

Hope that helps, thx!

Answer 3

There is an attribute called DisableConcurrentExecution, that prevents 2 Jobs of the same type running concurrently.

Though, in your case it could be best, to check if a task runs and skip accordingly.

Answer 4

Sounds like this could be something that you might be interested in: https://discuss.hangfire.io/t/job-reentrancy-avoidance-proposal/607/8

The discussion is about skipping jobs that would be executed concurrently to a already running job.

Answer 5

I was using the DisableConcurrentExecution attribute for my RecurringJob, but it was not working for me.

My mistake was that I was using it on my method and not on my interface.

[DisableConcurrentExecution(timeoutInSeconds: 10 * 60)]
Task SyncAllMyDataAsync();



RecurringJob.AddOrUpdate<IMySyncJobs>("Sync my data", x => x.SyncAllMyDataAsync(), "0 0 * * * *");

Answer 6

Yes.It is possible as below:

            RecurringJob.AddOrUpdate(Environment.MachineName, () => MyJob(Environment.MachineName), Cron.HourInterval(2));

and MyJob should define like this:

    public void MyJob(string taskId)
    {
        if (!taskId.Equals(Environment.MachineName))
        {
            return;
        }
        //Do whatever you job should do.
    }

Answer 7

I solved this problem. I hope it works for you

public class PreventConcurrentExecutionJobFilter : JobFilterAttribute, IClientFilter, IServerFilter
{
    public void OnCreating(CreatingContext filterContext)
    {
        var jobs = JobStorage.Current.GetMonitoringApi().ProcessingJobs(0, 100);
        if (jobs.Count(x => x.Value.Job.Type == filterContext.Job.Type && string.Join(".", x.Value.Job.Arguments) == string.Join(".", filterContext.Job.Arguments)) > 0)
        {
            filterContext.Canceled = true;
        }
    }

    public void OnPerformed(PerformedContext filterContext) { }

    void IClientFilter.OnCreated(CreatedContext filterContext) { }

    void IServerFilter.OnPerforming(PerformingContext filterContext) { }
}

Usings:

1. Add to global filters

GlobalJobFilters.Filters.Add(new PreventConcurrentExecutionJobFilter());

2. or by Abstract base job class

[PreventConcurrentExecutionJobFilter]
public abstract class IHangfireJob { 

}

2. or by Single job

[PreventConcurrentExecutionJobFilter]
public class MyJob { 

}

Answer 8

If you want to discard attempts to run something twice if it's already running you can always just do this (note no attributes applied):

    private static bool _isRunningUpdateOrders;
    public void UpdateOrders()
    {
        try
        {
            if (_isRunningUpdateOrders)
            {
                return; 
            }

            _isRunningUpdateOrders = true;

            // Logic...

        }
        finally 
        {
            _ isRunningUpdateOrders = false;
        }
   }

Edit: Please only use something like this as a quick fix, like if you've just discovered you have an issue and you're still evaluating better solutions :-) Or if you're lazy and you just want to 'sort of fix' the problem ;-)