Scheduler with cron in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when a Laravel scheduled task is set to run every minute using cron?

Consider this Laravel scheduler code snippet:

$schedule->command('emails:send')->everyMinute();

Assuming the system cron is properly configured to run Laravel's scheduler every minute, what is the expected behavior?

Laravel

$schedule->command('emails:send')->everyMinute();

A The command runs only once when the server starts and never again.

B The 'emails:send' command runs once every minute as expected.

C The command runs every hour instead of every minute.

D The command runs continuously without any delay.

💡 Hint

Think about how Laravel's scheduler and system cron work together.

Laravel's scheduler relies on the system cron to trigger the schedule:run command every minute. The everyMinute() method schedules the task to run each time schedule:run is called, so the command runs once every minute.

📝 Syntax

intermediate

Which Laravel scheduler syntax correctly schedules a task to run daily at 2:30 AM?

Choose the correct Laravel scheduler code to run a command daily at 2:30 AM.

A $schedule->command('backup:run')->dailyAt('2:30 PM');

B $schedule->command('backup:run')->dailyAt('02:30:00');

C $schedule->command('backup:run')->dailyAt('14:30');

D $schedule->command('backup:run')->dailyAt('02:30');

💡 Hint

Check the format Laravel expects for dailyAt() time strings.

Laravel's dailyAt() method expects a string in 'H:i' 24-hour format without seconds. '02:30' is interpreted as 2:30 AM. '02:30:00' includes seconds and is invalid. '14:30' is 2:30 PM, and '2:30 PM' is not a valid format.

🔧 Debug

advanced

Why does this Laravel scheduled command never run?

Given this scheduler code:

$schedule->command('report:generate')->cron('60 * * * *');

Why will the command never execute?

Laravel

$schedule->command('report:generate')->cron('60 * * * *');

A The cron expression '60 * * * *' is invalid because minutes must be 0-59.

B The command name 'report:generate' is incorrect and causes failure.

C The scheduler requires 'everyMinute()' instead of cron expressions.

D The cron expression runs only once a day, so it seems like it never runs.

💡 Hint

Check the valid range for minutes in cron syntax.

Cron expressions require the minute field to be between 0 and 59. '60' is invalid, so the scheduler ignores this task and it never runs.

❓ state_output

advanced

What is the output when a Laravel scheduled task uses 'withoutOverlapping' and the previous task is still running?

Consider this scheduler code:

$schedule->command('sync:data')->everyFiveMinutes()->withoutOverlapping();

If the 'sync:data' command takes 10 minutes to complete, what happens when the scheduler tries to run it again after 5 minutes?

Laravel

$schedule->command('sync:data')->everyFiveMinutes()->withoutOverlapping();

A The second run starts immediately, causing two overlapping processes.

B The scheduler queues the second run to start after the first finishes.

C The second run is skipped because the previous run is still active.

D The scheduler throws an error due to overlapping tasks.

💡 Hint

Think about what 'withoutOverlapping' means in Laravel scheduler.

'withoutOverlapping' prevents a scheduled task from starting if the previous instance is still running. So the second run is skipped to avoid overlap.

🧠 Conceptual

expert

How does Laravel's scheduler interact with system cron to run scheduled tasks?

Which statement best describes how Laravel's task scheduler works with system cron?

A System cron runs the 'schedule:run' command every minute, and Laravel decides which tasks to run based on their schedule.

B Laravel's scheduler replaces system cron and runs tasks independently without cron.

C System cron runs each scheduled task command directly without Laravel's scheduler involvement.

D Laravel's scheduler runs continuously in the background without needing system cron.

💡 Hint

Think about the role of system cron in triggering Laravel's scheduler.

Laravel's scheduler requires system cron to run the 'schedule:run' command every minute. Laravel then checks which tasks are due and runs them. Laravel does not replace cron or run tasks independently.