https://github.com/arcward/crong
Lightweight, straightforward cron parser, ticker and task scheduler for Go
https://github.com/arcward/crong
cron cron-expression cron-job cron-jobs cronjob cronjob-scheduler cronjobs crons crontab go golang scheduled-tasks scheduler scheduling task-scheduler tasks
Last synced: 5 months ago
JSON representation
Lightweight, straightforward cron parser, ticker and task scheduler for Go
- Host: GitHub
- URL: https://github.com/arcward/crong
- Owner: arcward
- License: agpl-3.0
- Created: 2024-02-26T00:10:43.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-08-27T16:38:50.000Z (9 months ago)
- Last Synced: 2024-12-30T23:44:26.981Z (5 months ago)
- Topics: cron, cron-expression, cron-job, cron-jobs, cronjob, cronjob-scheduler, cronjobs, crons, crontab, go, golang, scheduled-tasks, scheduler, scheduling, task-scheduler, tasks
- Language: Go
- Homepage:
- Size: 45.9 KB
- Stars: 1
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# crong
**Cron**g: Lightweight, straightforward cron expression parser, ticker
and task scheduler for your Golang projects.
## Usage
Create a schedule from a cron expression, calculate future/past schedules:
```go
package main
import (
"fmt"
"log"
"time"
"github.com/arcward/crong"
)
func main() {
schedule, err := crong.New("0 0 * * *", time.UTC)
if err != nil {
log.Fatal(err)
}
// Get the next (or most recent) scheduled time relative to the given time
fmt.Println("Next scheduled time:", schedule.Next(time.Now()))
fmt.Println("Previous scheduled time:", schedule.Prev(time.Now()))
// Check if the given time satisfies the schedule
if schedule.Matches(time.Now()) {
fmt.Println("It's time!")
}
}
```
Create a ticker that sends a tick on a channel whenever the cron
schedule fires, similar to `time.Ticker`:
```go
package main
import (
"context"
"log"
"time"
"github.com/arcward/crong"
)
func main() {
schedule, err := crong.New("@hourly", time.UTC)
if err != nil {
log.Fatal(err)
}
ticker := crong.NewTicker(context.Background(), schedule, 1 * time.Minute)
defer ticker.Stop()
select {
case t := <-ticker.C:
log.Printf("%s: Tick!", t)
}
}
```
Schedule a function to run whenever the schedule fires:
```go
package main
import (
"context"
"log"
"time"
"github.com/arcward/crong"
)
func main() {
schedule, err := crong.New("* * * * *", time.UTC)
if err != nil {
log.Fatal(err)
}
// MaxConcurrent=0 only allows the job to run sequentially, while
// increasing TickerReceiveTimeout can accommodate potentially long-running
// jobs, where you may not want the next tick to be dropped immediately.
// MaxConsecutiveFailures=10 will stop executing the given function if it
// returns a non-nil error ten times in a row.
opts := &crong.ScheduledJobOptions{
MaxConcurrent: 0,
TickerReceiveTimeout: 30 * time.Second,
MaxConsecutiveFailures: 10,
}
scheduledJob := crong.ScheduleFunc(
context.Background(),
schedule,
opts,
func(t time.Time) error {
log.Printf("Scheduled run for %s started at %s", t, time.Now())
return nil
},
)
defer scheduledJob.Stop(context.Background())
}
```
## Syntax
Supports standard cron syntax (see https://en.wikipedia.org/wiki/Cron), as well as less standard expressions.
For example, `5/10 4,5 * *` means "every 10 minutes starting at the 5th minute of the hour, for hours 4 and 5."
Days of the week are indexed 0-6, with 0 being Sunday, and can be referenced by
name (SUN, MON, TUE, WED, THU, FRI, SAT) or by number.
Months are indexed 1-12, and can be referenced by name
(JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC) or by number.
Cron macros supported:
- `@yearly` (or `@annually`) - Run once a year, midnight, Jan. 1
- `@monthly` - Run once a month, midnight, first of month
- `@weekly` - Run once a week, midnight between Saturday and Sunday
- `@daily` (or `@midnight`) - Run once a day, midnight
- `@hourly` - Run once an hour, beginning of hour
Other characters supported:
- `*`: Wildcard/Any value (ex: Every minute: `* * * * *`)
- `,`: Value list separator (ex: Minute 0 and 30 of every hour: `0,30 * * * *`)
- `-`: Range of values (ex: Minute 0-15 of every hour: `0-15 * * * *`)
- `/`: Step values (ex: Every 2nd minute from minute 10-20 of every hour: `10-20/2 * * * *`)
- `?`: No specific value (month, day of month, day of week only)
- `L`: Last day of month. When used, must be used alone in the day
field (ex: 12:30 on the last day of every month: `30 12 L * *`)