Schedule Recurring Tasks

In addition to queueing jobs to run in the background, it also supports scheduling recurring tasks to execute APIs or Commands at fixed intervals.

APIs and Commands can be scheduled to run at either a TimeSpan or CRON Expression interval, e.g:

CRON Expression Examples​

// Every Minute Expression
jobs.RecurringCommand<CheckUrlsCommand>(Schedule.Cron("* * * * *"));

// Every Minute Constant
jobs.RecurringCommand<CheckUrlsCommand>(Schedule.EveryMinute, new CheckUrls {
    Urls = urls
});

CRON Format​

You can use any unix-cron format expression supported by the HangfireIO/Cronos library:

|------------------------------- Minute (0-59)
|     |------------------------- Hour (0-23)
|     |     |------------------- Day of the month (1-31)
|     |     |     |------------- Month (1-12; or JAN to DEC)
|     |     |     |     |------- Day of the week (0-6; or SUN to SAT; or 7 for Sunday)
|     |     |     |     |
|     |     |     |     |
*     *     *     *     *

The allowed formats for each field include:

Matching all values​

To match all values for a field, use the asterisk: *, e.g here are two examples in which the minute field is left unrestricted:

• * 0 1 1 1 - the job runs every minute of the midnight hour on January 1st and Mondays.
• * * * * * - the job runs every minute (of every hour, of every day of the month, of every month, every day of the week, because each of these fields is unrestricted too).

Matching a range​

To match a range of values, specify your start and stop values, separated by a hyphen (-). Do not include spaces in the range. Ranges are inclusive. The first value must be less than the second.

The following equivalent examples run at midnight on Mondays, Tuesdays, Wednesdays, Thursdays, and Fridays (for all months):

• 0 0 * * 1-5
• 0 0 * * MON-FRI

Matching a list​

Lists can contain any valid value for the field, including ranges. Specify your values, separated by a comma (,). Do not include spaces in the list, e.g:

• 0 0,12 * * * - the job runs at midnight and noon.
• 0-5,30-35 * * * * - the job runs in each of the first five minutes of every half hour (at the top of the hour and at half past the hour).

TimeSpan Interval Examples​

jobs.RecurringCommand<CheckUrlsCommand>(Schedule.Interval(TimeSpan.FromMinutes(1)));

// With Example
jobs.RecurringApi(Schedule.Interval(TimeSpan.FromMinutes(1)), new CheckUrls {
    Urls = urls
});

That can be registered with an optional Task Name and Background Options, e.g:

jobs.RecurringCommand<CheckUrlsCommand>("Check URLs", Schedule.EveryMinute, 
   new() {
       RunCommand = true // don't persist job
   });

Idempotent Registration​

Scheduled Tasks are idempotent where the same registration with the same name will either create or update the scheduled task registration without losing track of the last time the Recurring Task, as such it's recommended to always define your App's Scheduled Tasks on Startup:

public class ConfigureBackgroundJobs : IHostingStartup
{
   public void Configure(IWebHostBuilder builder) => builder
     .ConfigureServices((context,services) => {
         services.AddPlugin(new CommandsFeature());
         services.AddPlugin(new BackgroundsJobFeature());
         services.AddHostedService<JobsHostedService>();
     }).ConfigureAppHost(afterAppHostInit: appHost => {
         var services = appHost.GetApplicationServices();

         var jobs = services.GetRequiredService<IBackgroundJobs>();
         
         // App's Scheduled Tasks Registrations:
         jobs.RecurringCommand<MyCommand>(Schedule.Hourly);
     });
}

Background Jobs Admin UI​

The last job the Recurring Task ran is also viewable in the Jobs Admin UI: