scheduled's Introduction

scheduled

scheduled implements an in-memory scheduler to run functions in a time loop. It also supports running functions with a CRON syntax scheduling.

Usage

Get

> go get github.com/hum/scheduled

Basic

Allows for a creation of simple functions, which get executed every Interval tick.

import "github.com/hum/scheduled"

// Create a new task via scheduled.NewTask
task := scheduled.NewTask(scheduled.TaskOpts{
  // The actual function to be ran
  Fn: func() error {
    fmt.Println("Hello from task!")
    return nil
  },
  // How often should the function be ran
  Interval: 10*time.Second,
})

// Initialise a new scheduler
scheduler := scheduled.NewScheduler()
defer scheduler.Stop()

// Add the task to the scheduler
scheduler.RegisterTask(task)

You can also bound the Interval with MaxIter to only allow N intervals to pass.

task := scheduled.NewTask(scheduled.TaskOpts{
  Fn: func() error {
    fmt.Println("Hello from task!")
    return nil
  },
  Interval: 10*time.Second,
  // Stops executing after 10 runs
  MaxIter: 10,
})

With start time and end time

You can also specify StartTime and/or EndTime to time bound the task's execution. StartTime allows the scheduler to wait until the specified time to execute the function, while EndTime is used with interval or CRON to end the execution of the task after a certain period of time passes.

task := scheduled.NewTask(scheduled.TaskOpts{
  Fn: func() error {
    fmt.Println("Hello from task!")
    return nil
  },
  Interval: 10*time.Second,
  // Starts the function in 5 hours, then runs it every 10 seconds
  StartTime: time.Now().Add(5*time.Hour),
  // Stops executing after 24 hours
  EndTime: time.Now().Add(24*time.Hour),
})

With CRON

A task supports a CRON syntax to act as the interval function. Use Cron to pass in a CRON string.

NOTE: Cron has a priority over Interval. If you pass both, Cron will be used.

task := scheduled.NewTask(scheduled.TaskOpts{
  Fn: func() error {
    fmt.Println("Hello from task!")
    return nil
  },
  // Run every minute
  Cron: "* * * * *",
})

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