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Diffstat (limited to 'modules/cron/doc.go')
| -rw-r--r-- | modules/cron/doc.go | 129 |
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diff --git a/modules/cron/doc.go b/modules/cron/doc.go deleted file mode 100644 index 258fe1ef..00000000 --- a/modules/cron/doc.go +++ /dev/null @@ -1,129 +0,0 @@ -/* -Package cron implements a cron spec parser and job runner. - -Usage - -Callers may register Funcs to be invoked on a given schedule. Cron will run -them in their own goroutines. - - c := cron.New() - c.AddFunc("Every hour on the half hour","0 30 * * * *", func() { fmt.Println("Every hour on the half hour") }) - c.AddFunc("Every hour","@hourly", func() { fmt.Println("Every hour") }) - c.AddFunc("Every hour and a half","@every 1h30m", func() { fmt.Println("Every hour thirty") }) - c.Start() - .. - // Funcs are invoked in their own goroutine, asynchronously. - ... - // Funcs may also be added to a running Cron - c.AddFunc("@daily", func() { fmt.Println("Every day") }) - .. - // Inspect the cron job entries' next and previous run times. - inspect(c.Entries()) - .. - c.Stop() // Stop the scheduler (does not stop any jobs already running). - -CRON Expression Format - -A cron expression represents a set of times, using 6 space-separated fields. - - Field name | Mandatory? | Allowed values | Allowed special characters - ---------- | ---------- | -------------- | -------------------------- - Seconds | Yes | 0-59 | * / , - - Minutes | Yes | 0-59 | * / , - - Hours | Yes | 0-23 | * / , - - Day of month | Yes | 1-31 | * / , - ? - Month | Yes | 1-12 or JAN-DEC | * / , - - Day of week | Yes | 0-6 or SUN-SAT | * / , - ? - -Note: Month and Day-of-week field values are case insensitive. "SUN", "Sun", -and "sun" are equally accepted. - -Special Characters - -Asterisk ( * ) - -The asterisk indicates that the cron expression will match for all values of the -field; e.g., using an asterisk in the 5th field (month) would indicate every -month. - -Slash ( / ) - -Slashes are used to describe increments of ranges. For example 3-59/15 in the -1st field (minutes) would indicate the 3rd minute of the hour and every 15 -minutes thereafter. The form "*\/..." is equivalent to the form "first-last/...", -that is, an increment over the largest possible range of the field. The form -"N/..." is accepted as meaning "N-MAX/...", that is, starting at N, use the -increment until the end of that specific range. It does not wrap around. - -Comma ( , ) - -Commas are used to separate items of a list. For example, using "MON,WED,FRI" in -the 5th field (day of week) would mean Mondays, Wednesdays and Fridays. - -Hyphen ( - ) - -Hyphens are used to define ranges. For example, 9-17 would indicate every -hour between 9am and 5pm inclusive. - -Question mark ( ? ) - -Question mark may be used instead of '*' for leaving either day-of-month or -day-of-week blank. - -Predefined schedules - -You may use one of several pre-defined schedules in place of a cron expression. - - Entry | Description | Equivalent To - ----- | ----------- | ------------- - @yearly (or @annually) | Run once a year, midnight, Jan. 1st | 0 0 0 1 1 * - @monthly | Run once a month, midnight, first of month | 0 0 0 1 * * - @weekly | Run once a week, midnight on Sunday | 0 0 0 * * 0 - @daily (or @midnight) | Run once a day, midnight | 0 0 0 * * * - @hourly | Run once an hour, beginning of hour | 0 0 * * * * - -Intervals - -You may also schedule a job to execute at fixed intervals. This is supported by -formatting the cron spec like this: - - @every <duration> - -where "duration" is a string accepted by time.ParseDuration -(http://golang.org/pkg/time/#ParseDuration). - -For example, "@every 1h30m10s" would indicate a schedule that activates every -1 hour, 30 minutes, 10 seconds. - -Note: The interval does not take the job runtime into account. For example, -if a job takes 3 minutes to run, and it is scheduled to run every 5 minutes, -it will have only 2 minutes of idle time between each run. - -Time zones - -All interpretation and scheduling is done in the machine's local time zone (as -provided by the Go time package (http://www.golang.org/pkg/time). - -Be aware that jobs scheduled during daylight-savings leap-ahead transitions will -not be run! - -Thread safety - -Since the Cron service runs concurrently with the calling code, some amount of -care must be taken to ensure proper synchronization. - -All cron methods are designed to be correctly synchronized as long as the caller -ensures that invocations have a clear happens-before ordering between them. - -Implementation - -Cron entries are stored in an array, sorted by their next activation time. Cron -sleeps until the next job is due to be run. - -Upon waking: - - it runs each entry that is active on that second - - it calculates the next run times for the jobs that were run - - it re-sorts the array of entries by next activation time. - - it goes to sleep until the soonest job. -*/ -package cron |