Rescheduling Hangfire Jobs using appSettings.json

Hangfire is a powerful tool to schedule a background job. With its simple-to-use API, one can easily register a background job using a couple of lines of code.

 RecurringJob.AddOrUpdate<DirectoryCleaner>("DirectoryCleaner", job => job.Cleanup(), Cron.Daily);
 RecurringJob.AddOrUpdate<CacheCleaner>("CacheCleaner", job => job.CleanCache(), Cron.Daily);

This code tells Hangfire to create two background jobs to run on everyday at midnight: “DirectoryCleaner” and “CacheCleaner”.

However, there are some drawbacks with this approach. If there’s a need to disable or to modify the occurrence of these jobs, you have 2 options:

1. Remove the job from the code, recompile and redeploy.
2. Using Hangfire Dashboard and delete the job.
   However, the job may get added back in when the app pool recycle.

---

Hangfire.Rescheduler

So, I created Hangfire.Rescheduler to allow more flexibility around job scheduling. Consider the following approach:

appSettings.json

{
  "jobOptions": {
    "schedules": [{
        "jobId": "CacheCleaner",
        "isEnabled": false,
        "cron": "0 1 * * *"
      },{
        "jobId": "DirectoryCleaner",
        "isEnabled": true,
        "cron": "0 1 * * *",
        "timezoneId": "UTC"
      },
    ]
  }
}

Program.cs

...
RecurringJob.AddOrUpdate<DirectoryCleaner>("DirectoryCleaner", job => job.Cleanup(), Cron.Daily);
RecurringJob.AddOrUpdate<CacheCleaner>("CacheCleaner", job => job.CleanCache(), Cron.Daily);

IServiceProvider services = ...
IConfigurationRoot root = ...

var options = root.getConfiguration<JobReschedulingOption>("JobOptions");
var jobRescheduler = services.GetService<IJobRescheduler>();
jobRescheduler.LoadSchedules(options);
...

IJobRescheduler allows you to modify your Hangfire jobs using appSettings.json (or other ways using JobReschedulingOption) . It provides a way to turn on/off, reschedule (using Cron expression) a job by its id.

This library is really simple to implement check out the code on github: https://github.com/bingzer/Hangfire.Rescheduler


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