73 lines
2.6 KiB
Markdown
73 lines
2.6 KiB
Markdown
---
|
|
stage: none
|
|
group: unassigned
|
|
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments
|
|
---
|
|
|
|
# Cron
|
|
|
|
Cron syntax is used to schedule when jobs should run.
|
|
|
|
You may need to use a cron syntax string to
|
|
create a [pipeline schedule](../../ci/pipelines/schedules.md),
|
|
or to prevent unintentional releases by setting a
|
|
[deploy freeze](../../user/project/releases/index.md#prevent-unintentional-releases-by-setting-a-deploy-freeze).
|
|
|
|
## Cron syntax
|
|
|
|
Cron scheduling uses a series of five numbers, separated by spaces:
|
|
|
|
```plaintext
|
|
# ┌───────────── minute (0 - 59)
|
|
# │ ┌───────────── hour (0 - 23)
|
|
# │ │ ┌───────────── day of the month (1 - 31)
|
|
# │ │ │ ┌───────────── month (1 - 12)
|
|
# │ │ │ │ ┌───────────── day of the week (0 - 6) (Sunday to Saturday)
|
|
# │ │ │ │ │
|
|
# │ │ │ │ │
|
|
# │ │ │ │ │
|
|
# * * * * * <command to execute>
|
|
```
|
|
|
|
(Source: [Wikipedia](https://en.wikipedia.org/wiki/Cron))
|
|
|
|
In cron syntax, the asterisk (`*`) means 'every,' so the following cron strings
|
|
are valid:
|
|
|
|
- Run once an hour at the beginning of the hour: `0 * * * *`
|
|
- Run once a day at midnight: `0 0 * * *`
|
|
- Run once a week at midnight on Sunday morning: `0 0 * * 0`
|
|
- Run once a month at midnight of the first day of the month: `0 0 1 * *`
|
|
- Run once a month on the 22nd: `0 0 22 * *`)
|
|
- Run once a month on the 2nd Monday: `0 0 * * 1#2`
|
|
- Run once a year at midnight of 1 January: `0 0 1 1 *`
|
|
- Run every other Sunday at 0900 hours: `0 9 * * sun%2`
|
|
|
|
For complete cron documentation, refer to the
|
|
[crontab(5) — Linux manual page](https://man7.org/linux/man-pages/man5/crontab.5.html).
|
|
This documentation is accessible offline by entering `man 5 crontab` in a Linux or MacOS
|
|
terminal.
|
|
|
|
## Cron examples
|
|
|
|
```plaintext
|
|
# Run at 7:00pm every day:
|
|
0 19 * * *
|
|
|
|
# Run every minute on the 3rd of June:
|
|
* * 3 6 *
|
|
|
|
# Run at 06:30 every Friday:
|
|
30 6 * * 5
|
|
```
|
|
|
|
More examples of how to write a cron schedule can be found at
|
|
[crontab.guru](https://crontab.guru/examples.html).
|
|
|
|
## How GitLab parses cron syntax strings
|
|
|
|
GitLab uses [`fugit`](https://github.com/floraison/fugit) to parse cron syntax
|
|
strings on the server and [cron-validator](https://github.com/TheCloudConnectors/cron-validator)
|
|
to validate cron syntax in the browser. GitLab uses
|
|
[`cRonstrue`](https://github.com/bradymholt/cRonstrue) to convert cron to human-readable strings
|
|
in the browser.
|