cronschedule

cronschedule is a go module that provides the ability to parse an execution schedule specified in cron format and then generate the next execution times based on any start time. It's specifically intended to be used as a component of job scheduling and execution implementations.

Usage

// Parsing the schedule.
cronSchedule = "* * * * *"
schedule, err := cronschedule.Parse(cronSchedule)
if err != nil {
    // Handle errors. Generally thrown for formatting or invalid values.
    panic(err)
}

// Find the next 5 execution times based on the schedule after right now.
nextExecutions := schedule.NextExecutions(time.Now(), 5)
fmt.Println(nextExecutions)

// Find the next single time using the convenience method.
next := schedule.NextExecution(time.Now())
fmt.Println(next)

// Checking if an execution should run at specific time.
t := time.Date(2020,time.December,, 1, 1, 1, 1, 0, time.Locale)
if schedule.ShouldExecute(t) {
    fmt.Println("should execute at %v!", t)
}

// Checking if an execution should run right now.
if schedule.ShouldExecuteNow(time.Now()) {
    fmt.Println("should execute!")
}

Support

• Only supports scheduling including all 5 fields separated by a single space.
• Per UNIX spec, utilizes an OR when both day_of_week and day_of_month are specified as anything but *.
• Text version of days, e.g. SUN-SAT, are not currently supported.
• Text versions of months, e.g. JAN-DEC, are not currently supported.
• Predefined schedules, e.g @yearly are not supported.
• Years are not supported.
• Unsupported non-standard characters include [L, W, #, ?]
• Does support / for intervals. Specifically the job will increment by the value of b in a/b starting with a.

Day Of Month / Day Of Week Logic Table

Day Of Month	Day Of Week	Output
*	*	All days are included.
*	Non * Value	Only days that match Day Of Week are included.
Non * Value	*	Only days that match Day Of Month are included.
Non * Value	Non * Value	All value that match Day Of Month or Day Of Year. Note: If * is included in either it can include all days and make the other irrelevant.