Scheduling Tasks

Serverless Cloud also supports scheduled tasks, which you can create using the schedule helper. You can either use the .every() method for having tasks repeat on a regular time interval.Or you can use the .cron() method to have more fine-grained control.

Scheduling tasks with .every()

If you know you need a task to repeat every hour, or every 5 days, you can use the .every() method. This method takes two arguments, a rate expression and the function you'd like to run.

For example, the following will log "I run every hour!" every hour:

schedule.every("1 hour", () => {
  // This code block will run every hour!
  console.log("I run every hour!");
});

A rate expression consists of a numeric value and a unit. Valid units are minute, minutes, hour, hours, day and days.

Scheduling tasks with .cron()

If you need more control over your scheduled tasks, you can use the .cron() method. This method also takes two arguments, a cron expression and the function you'd like to run.

For example, the following will log "I run on Tuesdays!" every Tuesday at midnight UTC:

schedule.cron("0 0 * * TUE *", () => {
  // This code block will run at midnight on Tuesdays!
  console.log("I run on Tuesdays!");
});

Cron expressions consist of six fields:

Wildcards

• The , (comma) wildcard includes additional values. In the Month field, JAN,FEB,MAR would include January, February, and March.
• The - (dash) wildcard specifies ranges. In the Day field, 1-15 would include days 1 through 15 of the specified month.
• The _ (asterisk) wildcard includes all values in the field. In the Hours field, _ would include every hour. You cannot use * in both the Day-of-month and Day-of-week fields. If you use it in one, you must use ? in the other.
• The / (forward slash) wildcard specifies increments. In the Minutes field, you could enter 1/10 to specify every tenth minute, starting from the first minute of the hour (for example, the 11th, 21st, and 31st minute, and so on).
• The ? (question mark) wildcard specifies one or another. In the Day-of-month field you could enter 7 and if you didn't care what day of the week the 7th was, you could enter ? in the Day-of-week field.
• The L wildcard in the Day-of-month or Day-of-week fields specifies the last day of the month or week.
• The W wildcard in the Day-of-month field specifies a weekday. In the Day-of-month field, 3W specifies the weekday closest to the third day of the month.
• The # wildcard in the Day-of-week field specifies a certain instance of the specified day of the week within a month. For example, 3#2 would be the second Tuesday of the month: the 3 refers to Tuesday because it is the third day of each week, and the 2 refers to the second day of that type within the month.