CronQuery
CronQuery is scheduled via CRON expressions.
# CRON Expressions
CRON is a time-based job scheduler. Jobs run periodically at fixed times configured using a six-field expression.
┌──── second (0-59)
│ ┌───── minute (0-59)
│ │ ┌───── hour (0-23)
│ │ │ ┌───── day of month (1-31)
│ │ │ │ ┌───── month (1-12)
│ │ │ │ │ ┌───── day of week (0-6)
│ │ │ │ │ │
* * * * * *
| Field | Allowed values | Special characters |
|---|---|---|
| Second | 0-59 | * - , / |
| Minute | 0-59 | * - , / |
| Hour | 0-23 | * - , / |
| Day of month | 1-31 | * - , / L W |
| Month | 1-12 | * - , / |
| Day of week | 0-6 | * - , / L # |
The days of the week start on Sunday.
# Special characters
The following table shows the special characters present in CRON syntax and their respective meanings.
| Character | Description | Example |
|---|---|---|
* (all) | Every time unit | Asterisk in the hour means "every hour" |
- (range) | Range of values | 1-5, which is equivalent to 1,2,3,4,5 |
, (list) | List of values | 2,4,6,8 |
/ (increment) | Step values | */6 in the hour means "every 6 hours", which is equivalent to 0,6,12,18 |
L (last) | Last day of month or last X day of week | In month L means 31 for January or day 28 for February (non-leap years), in day of week 5L means "the last Friday of the month" |
W (weekday) | Weekday (Monday to Friday) nearest the given day | If you specify 15W and 15th is a Saturday the trigger fires on Friday the 14th, however for 1W and 1th is a Saturday the trigger fires on Monday the 3rd (because it does not exceed the limit of days of the month), if the 15h is a Sunday the trigger fires on Monday the 16th and if 15th is a weekday the trigger fires that day |
# (occurrence) | The nth day of the month | 5#3 means the third Friday of the month |
# Supported combinations
CRON allows the combination of subexpressions to produce a more complex CRON expression. The following list shows the combinations supported by CronQuery:
*: Every time unit.00-00: Range of values.*/00: Every time unit skipping a given number of values.00/00: Skipping a given number of values starting at specific value.00-00/00: Skipping a given number of values in a given range of values.00,00-00,00/00,00-00/00: List of values (you can produce variations). List can only contains single numbers, range, increment and range combined with increment.L(day of month only): Last day of the month (including weekend).LW(day of month only): Last weekday (Monday to Friday) of the month.L-00(day of month only): Days (1-31) before the last day of month.00W(day of month only): Weekday nearest the given day (1-31).0L(day of week only): Last day of week (0-6) of the month.00#0(day of week only): The nth (1-5) day of the month.
Read zero as any numeric value that you pass to the expression.
# Examples
The following table shows some examples of CRON expressions and their respective meanings.
| Expression | Description |
|---|---|
0 0 12 * * * | At 12:00 PM every day |
0 0 18 L * * | At 6:00 PM on the last day of every month |
0 0 18 L-3 * * | At 6:00 PM 3 days before the last day of the month |
0 0 0 * */6 * | At 12:00 AM every 6 months |
0 0 0 5,15,25 * * | At 12:00 AM, on day 5, 15, and 25 of the month |
0 */5 * * * * | Every 5 minutes |
0 0 8-18/2 * * * | Every 2 hours between 8:00 AM and 6:00 PM |
0 0 10 * * 1#3 | At 10:00 AM on the third Monday of every month |
crontab.guru is a great tool to help you create CRON expressions.