如何在队列中的作业之间添加 2 分钟的延迟？

Question

I am using Hangfire in ASP.NET Core with a server that has 20 workers, which means 20 jobs can be enqueued at the same time.

What I need is to enqueue them one by one with 2 minutes delay between each one and another. Each job can take 1-45 minutes, but I don't have a problem running jobs concurrently, but I do have a problem starting 20 jobs at the same time. That's why changing the worker count to 1 is not practical for me (this will slow the process a lot).

The idea is that I just don't want 2 jobs to run at the same second since this may make some conflicts in my logic, but if the second job started 2 minutes after the first one, then I am good.

How can I achieve that?

Answer 1

You can use BackgroundJob.Schedule() to run your job run at a specific time:

BackgroundJob.Schedule(() => Console.WriteLine("Hello"), dateTimeToExecute);

Based on that set a date for the first job to execute, and then increase this date to 2 minutes for each new job.

Something like this:

var dateStartDate = DateTime.Now;
foreach (var j in listOfjobsToExecute)
{
    BackgroundJob.Schedule(() => j.Run(), dateStartDate);
    dateStartDate = dateStartDate.AddMinutes(2);
}

See more here: https://docs.hangfire.io/en/latest/background-methods/calling-methods-with-delay.html?highlight=delay