SkipWhenPreviousJobIsRunningAttribute.cs

SkipWhenPreviousJobIsRunningAttribute.cs

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using System;
using System.Collections.Generic;
using Hangfire.Client;
using Hangfire.Common;
using Hangfire.States;
using Hangfire.Storage;

namespace ConsoleApp28
{
    public class SkipWhenPreviousJobIsRunningAttribute : JobFilterAttribute, IClientFilter, IApplyStateFilter
    {
        public void OnCreating(CreatingContext context)
        {
            var connection = context.Connection as JobStorageConnection;

            // We can't handle old storages
            if (connection == null) return;

            // We should run this filter only for background jobs based on 
            // recurring ones
            if (!context.Parameters.ContainsKey("RecurringJobId")) return;

            var recurringJobId = context.Parameters["RecurringJobId"] as string;

            // RecurringJobId is malformed. This should not happen, but anyway.
            if (String.IsNullOrWhiteSpace(recurringJobId)) return;

            var running = connection.GetValueFromHash($"recurring-job:{recurringJobId}", "Running");
            if ("yes".Equals(running, StringComparison.OrdinalIgnoreCase))
            {
                context.Canceled = true;
            }
        }

        public void OnCreated(CreatedContext filterContext)
        {
        }

        public void OnStateApplied(ApplyStateContext context, IWriteOnlyTransaction transaction)
        {
            if (context.NewState is EnqueuedState)
            {
                var recurringJobId = JobHelper.FromJson<string>(context.Connection.GetJobParameter(context.BackgroundJob.Id, "RecurringJobId"));
                if (String.IsNullOrWhiteSpace(recurringJobId)) return;

                transaction.SetRangeInHash(
                    $"recurring-job:{recurringJobId}",
                    new[] { new KeyValuePair<string, string>("Running", "yes") });
            }
            else if ((context.NewState.IsFinal && !FailedState.StateName.Equals(context.OldStateName, StringComparison.OrdinalIgnoreCase)) || 
                     (context.NewState is FailedState))
            {
                var recurringJobId = JobHelper.FromJson<string>(context.Connection.GetJobParameter(context.BackgroundJob.Id, "RecurringJobId"));
                if (String.IsNullOrWhiteSpace(recurringJobId)) return;

                transaction.SetRangeInHash(
                    $"recurring-job:{recurringJobId}",
                    new []{ new KeyValuePair<string, string>("Running", "no") });
            }
        }

        public void OnStateUnapplied(ApplyStateContext context, IWriteOnlyTransaction transaction)
        {
        }
    }
}

Thanks for sharing!
Please update lines with deprecated methods:
https://gist.github.com/odinserj/a6ad7ba6686076c9b9b2e03fcf6bf74e#file-skipwhenpreviousjobisrunningattribute-cs-L52
https://gist.github.com/odinserj/a6ad7ba6686076c9b9b2e03fcf6bf74e#file-skipwhenpreviousjobisrunningattribute-cs-L43

To new ones:
var recurringJobId = SerializationHelper.Deserialize(context.Connection.GetJobParameter(context.BackgroundJob.Id, "RecurringJobId"));

https://gist.github.com/odinserj/a6ad7ba6686076c9b9b2e03fcf6bf74e#file-skipwhenpreviousjobisrunningattribute-cs-L50 is also invalid now that IsFinal is false for FailedState unless there is bug in the way it is coded.

I have found a bug. When my job failed, it never runs again. The bug in line 28: var running = connection.GetValueFromHash($"recurring-job:{recurringJobId}", "Running"); it always returns yes. If I go to the queue, there are no running job but failed.

P.S. My recurringJobId is always the same for every new job.

Does anyone know how to fix it?

Ok, I found a solution.
The statement in line 50 needs to be uncommented:

else if (context.NewState.IsFinal || context.NewState is FailedState)

How can I use this on background enqueued jobs? This SkipWhenPreviousJobIsRunningAttribute seems specific to recurring jobs, I would like the current event driven job to complete before the next one can start even though it has been triggered.

I would like to hear the solution for a background job too! Now I have bumped into the issue that in 30 mins, while background job is still running, the same job is being run again! And I cannot see any setting with this "magic" 30 minutes...

It looks like you have to buy a subscription to get the Hangfire.Ace extensibility set to use the Hangfire.Throttling package. See Concurrency & Rate Limiting.

How can I use this on background enqueued jobs? This SkipWhenPreviousJobIsRunningAttribute seems specific to recurring jobs, I would like the current event driven job to complete before the next one can start even though it has been triggered.

You could make a named queue with a size of 1.

app.UseHangfireServer(new BackgroundJobServerOptions
{
    WorkerCount = 1, 
    Queues = new[] { "queueName" }
});

Then apply [Queue("queueName")] to your job.

CAUTION: If you have two servers running each will start a queue can process a maximum of one job. So if you just want one per server then this will work. If you really cannot have two at a time for some business reason then this won't work with multiple servers.

@simeyla good idea. I am just not clear on what you intended to say with you "CAUTION" note from above.I have tested and your approch seems to be actually working fine when there are multiple servers where one of them is linked to a queue that is also used to enqueue a background job. I have tested by enqueuing several jobs and all of them are consistently being executed one by one by the server that has been linked to the queue used to enqueue each of the background jobs.
Am I missing your something?

Thanks!

hello there, I have a problem with this code. After some time (cannot really say what is some) some of my recurring jobs which are decorated with this attribute are stopping execution. I mean they are immediately canceled after new execution and when I placed logger there here is what it produces:

2023-11-28 16:05:33.7064|INFO|Namespace.Jobs.Hangfire.Attributes.SkipWhenPreviousJobIsRunningAttribute|running: yes
2023-11-28 16:05:33.7064|INFO|Namespace.Jobs.Hangfire.Attributes.SkipWhenPreviousJobIsRunningAttribute|Job will be canceled

and here is code in C#

var logger = new NLogFactory().Create(this);
string running = connection.GetValueFromHash($"recurring-job:{recurringJobId}", "Running");
logger.Info($"running: {running}");
if ("yes".Equals(running, StringComparison.OrdinalIgnoreCase))
{
    logger.Info($"Job will be canceled");
    context.Canceled = true;
}

I don't know why is it happening, but it won't trigger from this moment... I am using SQLite file as DB.

@frozzen10 The issue you're experiencing might be because the "Running" status of the job is not being reset properly when the job fails or when it's in a final state. This could cause the job to be immediately canceled on the next execution because the system thinks it's still running. To fix this, you should ensure that the "Running" status is reset in all cases when the job is in a final state, not just when it's not in a FailedState.

in OnStateApplied
`
var recurringJobId = SerializationHelper.Deserialize(
context.Connection.GetJobParameter(context.BackgroundJob.Id, "RecurringJobId"));

if (string.IsNullOrWhiteSpace(recurringJobId)) return;

if (context.NewState is EnqueuedState)
{
transaction.SetRangeInHash(
$"recurring-job:{recurringJobId}",
new[] {new KeyValuePair<string, string>("Running", "yes")});
}
else if (context.NewState.IsFinal)
{
transaction.SetRangeInHash(
$"recurring-job:{recurringJobId}",
new[] {new KeyValuePair<string, string>("Running", "no")});
}
`