Cron is a software utility that specifies commands to run on a given schedule.
Inspired with spring-framework blog
post: link
Library provides functionality that describes
in: link
Written in C and designed specifically for embedded devices.
- No dynamic or static memory allocations
- Time zones and DST rules support
- All Quartz fields support
- Composite quartz field support
- No
time.hlibrary dependencies - Full test coverage
- Not all composite quartz fields like:
"0 0 0 1W,15,LW * ?"is supported - No year field support
How to add CPM to the project, check the link
CPMAddPackage(
NAME CronExpression
GITHUB_REPOSITORY ximtech/CronExpression
GIT_TAG origin/main
)
target_link_libraries(${PROJECT_NAME} CronExpression)add_executable(${PROJECT_NAME}.elf ${SOURCES} ${LINKER_SCRIPT})
# For Clion STM32 plugin generated Cmake use
target_link_libraries(${PROJECT_NAME}.elf CronExpression)- The Cron pattern consists of six or seven space-separated fields
┌───────────── second (0-59)
│ ┌───────────── minute (0 - 59)
│ │ ┌───────────── hour (0 - 23)
│ │ │ ┌───────────── day of the month (1 - 31)
│ │ │ │ ┌───────────── month (1 - 12) (or JAN-DEC)
│ │ │ │ │ ┌───────────── day of the week (0 - 7)
│ │ │ │ │ │ (or MON-SUN -- 0 or 7 is Sunday)
│ │ │ │ │ │
* * * * * *
| Cron Expression | Meaning |
|---|---|
0 0 * * * * |
top of every hour of every day |
*/10 * * * * * |
every ten seconds |
0 0 8-10 * * * |
8, 9 and 10 o’clock of every day |
0 0 6,19 * * * |
6:00 AM and 7:00 PM every day |
0 0/30 8-10 * * * |
8:00, 8:30, 9:00, 9:30, 10:00 and 10:30 every day |
0 0 9-17 * * MON-FRI |
on the hour nine-to-five weekdays |
0 0 0 25 12 ? |
every Christmas Day at midnight |
- You can use these macros instead of the six-digit value
| Macro | Meaning |
|---|---|
@yearly (or @annually) |
once a year 0 0 0 1 1 * |
@monthly |
once a month 0 0 0 1 * * |
@weekly |
once a week 0 0 0 * * 0 |
@daily (or @midnight) |
once a day 0 0 0 * * * |
@hourly |
once an hour, 0 0 * * * * |
| Cron Expression | Meaning |
|---|---|
0 0 0 L * * |
last day of the month at midnight |
0 0 0 L-3 * * |
third-to-last day of the month at midnight |
0 0 0 * * 5L |
last Friday of the month at midnight |
0 0 0 * * THUL |
last Thursday of the month at midnight |
0 0 0 2,3,L * * |
on the 2nd, 3rd and last day of the month at midnight |
0 0 0 3-8,L * * |
between 3rd and 8th, and last day of the month at midnight |
| Cron Expression | Meaning |
|---|---|
0 0 0 1W * * |
first weekday of the month at midnight |
0 0 0 LW * * |
last weekday of the month at midnight |
| Cron Expression | Meaning |
|---|---|
0 0 0 ? * 5#2 |
the second Friday in the month at midnight |
0 0 0 ? * MON#1 |
the first Monday in the month at midnight |
#include "CronExpression.h"
CronExpression cron;
CronStatus status = parseCronExpression(&cron, "0 */2 1-4 * * *");
if (status != CRON_OK) { // check for error
printf("ERROR! No: %d\n", status);
return -1;
}
DateTime current = dateTimeNow();
DateTime next = nextCronDateTime(&cron, ¤t); CronExpression cron;
parseCronExpression(&cron, "0 0 9 * * *");
TimeZone zone = timeZoneOf("Europe/Amsterdam"); // create time zone
ZonedDateTime last = zonedDateTimeOf(2021, 3, 27, 9, 0, 0, 0, &zone); // Amsterdam winter time has 3600s UTC offset, and clock is moved one hour forward 28 march at 01:00 o'clock
ZonedDateTime actual = nextCronZonedDateTime(&cron, &last); // moving from summer to winter time
ZonedDateTime expected = zonedDateTimeOf(2021, 3, 28, 9, 0, 0, 0, &zone); // summer time has 7200s UTC offset
assert_true(isDateTimeEquals(&actual.dateTime, &expected.dateTime)); // check that dates calculated correctly
assert_true(last.offset == 3600);
assert_true(actual.offset == 7200);