how to run yearly recurring job using cron

问题

Hangfire is using ncrontab to run recurring job.

Does this below contab run every weekly Monday at 12 am for only 2017?

0 0 * * 1

How can I make sure it runs only for 2017 or every year?

回答1:

Hangfire uses NCrontab library. As you could see, this lib provides a way to rapidly test its own functionality. Just open C# Interactive window in Visual Studio and paste a code like below:

#r "C:\Users\YOUR_USER\.nuget\packages\ncrontab\3.3.0\lib\netstandard1.0\NCrontab.dll"
using NCrontab;
var s = CrontabSchedule.Parse("0 0 * * 1");
var start = new DateTime(2000, 1, 1);
var end = start.AddYears(12);
var occurrences = s.GetNextOccurrences(start, end);
Console.WriteLine(string.Join(Environment.NewLine, 
    from t in occurrences
    select $"{t:ddd, dd MMM yyyy HH:mm}"));

Another way is to use online crontab visualizer. For example: cron.schlitt.info.

Both tools give the same result: your cron expression means "run each Monday forever".

来源：https://stackoverflow.com/questions/43933521/how-to-run-yearly-recurring-job-using-cron