Scheduler with cron in Laravel - Step-by-Step Execution

Concept Flow - Scheduler with cron

Define Scheduled Task

↓

Add Task to Kernel Schedule()

↓

Set Cron Job on Server

↓

Cron Runs Every Minute

↓

Laravel Checks Scheduled Tasks

↓

Run Due Tasks

↓

Task Executes

↓

Wait for Next Minute

↩Back to Cron Runs Every Minute

The flow shows how you define tasks in Laravel, set up a cron job to run every minute, and Laravel runs the scheduled tasks when due.

Execution Sample

Laravel

protected function schedule(Schedule $schedule)
{
    $schedule->command('emails:send')->dailyAt('13:00');
}

This code schedules a command to run daily at 1 PM.

Execution Table

Step	Action	Time	Task Due?	Task Run?
1	Cron runs	12:59	No	No
2	Cron runs	13:00	Yes	Yes - emails:send command runs
3	Cron runs	13:01	No	No
4	Cron runs	13:02	No	No
5	Cron runs	13:03	No	No

💡 Cron runs every minute; task runs only at scheduled time 13:00

Variable Tracker

Variable	Start	After 12:59	After 13:00	After 13:01	Final
Current Time	12:58	12:59	13:00	13:01	13:03
Task Due	False	False	True	False	False
Task Run	No	No	Yes	No	No

Key Moments - 3 Insights

Why doesn't the task run at 12:59 even though cron runs every minute?

Because the task is scheduled to run daily at 13:00 only. At 12:59, the task is not due, so Laravel skips running it (see execution_table step 1).

How does Laravel know when to run the task?

Laravel checks the current time each minute when cron triggers it. If the current time matches the scheduled time (13:00), it runs the task (see execution_table step 2).

What happens if the cron job is not set up on the server?

Laravel's scheduler won't run automatically because cron triggers Laravel's schedule:run command every minute. Without cron, scheduled tasks never execute.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'Task Run' at step 3 (time 13:01)?

A Yes

B No

C Maybe

D Error

💡 Hint

Check the 'Task Run?' column at step 3 in the execution_table.

At which step does the task become due and run?

A Step 2

B Step 1

C Step 4

D Step 5

💡 Hint

Look for 'Task Due?' and 'Task Run?' columns in execution_table.

If the cron job runs every 5 minutes instead of every minute, how would the execution_table change?

A Task runs multiple times per minute

B Task runs every minute regardless

C Task runs only if cron runs at 13:00 exactly

D Task never runs

💡 Hint

Think about how often Laravel checks scheduled tasks based on cron frequency.

Concept Snapshot

Laravel Scheduler with cron:
- Define tasks in app/Console/Kernel.php schedule() method
- Set server cron to run 'php artisan schedule:run' every minute
- Laravel checks tasks each minute and runs those due
- Tasks run only at their scheduled times
- Cron triggers Laravel scheduler, without cron tasks won't run

Full Transcript

In Laravel, you define scheduled tasks inside the schedule() method of the Console Kernel. You then set up a cron job on your server to run the command 'php artisan schedule:run' every minute. Each time cron runs, Laravel checks if any scheduled tasks are due to run at that current time. If a task is due, Laravel runs it; otherwise, it waits for the next minute. For example, a task scheduled to run daily at 13:00 will only run when the cron triggers at exactly 13:00. If cron is not set up, scheduled tasks will never run automatically. This setup allows Laravel to manage task scheduling efficiently using a single cron entry.