Scheduler with cron in Laravel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of Laravel's scheduler?

Laravel's scheduler allows you to define scheduled tasks inside your application code instead of managing separate cron entries. It helps automate repetitive tasks like sending emails or cleaning databases.

beginner

How do you register a scheduled task in Laravel?

You register scheduled tasks inside the <code>schedule()</code> method of the <code>App\Console\Kernel</code> class using methods like <code>->command()</code> or <code>->call()</code> with timing methods like <code>->daily()</code> or <code>->everyMinute()</code>.

beginner

What is the cron entry you add to your server to run Laravel's scheduler?

You add a single cron entry that runs every minute: * * * * * php /path-to-your-project/artisan schedule:run >> /dev/null 2>&1. This triggers Laravel's scheduler to check and run due tasks.

intermediate

How can you run a scheduled task only on weekdays in Laravel?

Use the weekdays() method in the scheduler chain. For example: $schedule->command('emails:send')->weekdays()->at('13:00'); runs the task at 1 PM Monday to Friday.

intermediate

What is the benefit of using Laravel's scheduler over direct cron jobs for each task?

Laravel's scheduler centralizes task scheduling in code, making it easier to manage, test, and deploy. You only need one cron entry, reducing server complexity and risk of errors.

What command does Laravel's scheduler run every minute via cron?

A php artisan schedule:run

B php artisan cron:run

C php artisan task:run

D php artisan schedule:execute

The correct command is php artisan schedule:run, which Laravel uses to check and run scheduled tasks.

Where do you define scheduled tasks in a Laravel app?

A In <code>routes/web.php</code>

B In <code>App\Console\Kernel.php</code>

C In <code>config/scheduler.php</code>

D In <code>app/Http/Controllers/Scheduler.php</code>

Scheduled tasks are defined in the schedule() method inside App\Console\Kernel.php.

How often should the cron job for Laravel scheduler run?

A Every hour

B Every day

C Every minute

D Every second

The cron job runs every minute to check if any scheduled tasks are due.

Which method schedules a task to run daily at midnight?

A ->daily()

B ->hourly()

C ->everyMinute()

D ->weekly()

The ->daily() method schedules a task to run once every day at midnight.

How do you schedule a task to run only on weekdays in Laravel?

A ->monthly()

B ->weekends()

C ->daily()

D ->weekdays()

The ->weekdays() method restricts the task to run Monday through Friday.

Explain how Laravel's scheduler works with cron to automate tasks.

Think about how one cron job triggers Laravel to handle many tasks.

Describe how to define and schedule a command to run every day at 2 AM only on weekdays in Laravel.

Focus on the methods to set time and days in the scheduler.

Practice

1. What is the main purpose of Laravel's scheduler when using cron expressions?

easy

A. To create database migrations automatically

B. To manually execute commands from the terminal

C. To automate running tasks at specified times without manual intervention

D. To generate user authentication scaffolding

Solution

1. Step 1: Understand Laravel scheduler role

   Laravel scheduler automates running tasks like commands or jobs at set times.

2. Step 2: Identify cron usage

   Cron expressions define when tasks run automatically without manual input.

3. Final Answer:

   To automate running tasks at specified times without manual intervention -> Option C

4. Quick Check:

   Scheduler automates tasks [OK]

Hint: Scheduler automates tasks on schedule, not manual commands [OK]

Common Mistakes:

• Confusing scheduler with manual command execution
• Thinking scheduler creates migrations
• Assuming scheduler generates UI code

2. Which of the following is the correct way to schedule a command to run every day at midnight in Laravel's app/Console/Kernel.php?

easy

A. $schedule->command('emails:send')->hourly();

B. $schedule->command('emails:send')->dailyAt('00:00');

C. $schedule->command('emails:send')->cron('0 12 * * *');

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

Solution

1. Step 1: Identify daily midnight syntax

   Laravel's dailyAt('00:00') schedules a command at midnight daily.

2. Step 2: Check other options

   everyMinute() runs every minute, cron('0 12 * * *') runs at noon, hourly() runs every hour.

3. Final Answer:

   $schedule->command('emails:send')->dailyAt('00:00'); -> Option B

4. Quick Check:

   dailyAt('00:00') = midnight daily [OK]

Hint: dailyAt('00:00') means every day at midnight [OK]

Common Mistakes:

• Using cron('0 12 * * *') which runs at noon, not midnight
• Confusing everyMinute() with daily scheduling
• Using hourly() instead of dailyAt()

3. Given this scheduler code in app/Console/Kernel.php:

$schedule->command('backup:run')->cron('0 3 * * 1');

When will the backup:run command execute?

medium

A. Every hour on the hour

B. Every day at 3:00 AM

C. Every Sunday at 3:00 AM

D. Every Monday at 3:00 AM

Solution

1. Step 1: Decode cron expression '0 3 * * 1'

   The fields mean: minute=0, hour=3, day=any, month=any, weekday=1 (Monday).

2. Step 2: Interpret execution time

   The command runs at 3:00 AM every Monday.

3. Final Answer:

   Every Monday at 3:00 AM -> Option D

4. Quick Check:

   cron('0 3 * * 1') = Monday 3AM [OK]

Hint: Cron weekday 1 means Monday at specified time [OK]

Common Mistakes:

• Confusing weekday 1 with Sunday
• Assuming it runs daily instead of weekly
• Misreading hour or minute fields

4. You wrote this in app/Console/Kernel.php:

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

What is the problem with this cron expression?

medium

A. Minute value 60 is invalid; minutes range from 0 to 59

B. Hour value is missing

C. Day of month is invalid

D. Cron expression is missing the command name

Solution

1. Step 1: Check cron minute field

   The first field is minute; valid values are 0 to 59. 60 is invalid.

2. Step 2: Confirm other fields

   Other fields are valid, but minute 60 causes syntax error.

3. Final Answer:

   Minute value 60 is invalid; minutes range from 0 to 59 -> Option A

4. Quick Check:

   Minute must be 0-59, 60 is invalid [OK]

Hint: Minutes in cron go 0-59, never 60 [OK]

Common Mistakes:

• Using 60 as minute value
• Ignoring cron field ranges
• Assuming missing hour causes error here

5. You want to schedule a Laravel command to run every weekday at 6:30 PM but only if a certain feature flag is enabled. Which is the best way to implement this in app/Console/Kernel.php?

hard

A. Use if (config('features.enable_task')) { $schedule->command('task:run')->weekdays()->at('18:30'); }

B. Schedule the command daily at 18:30 without condition

C. Use cron expression '30 18 * * 0-6' to run every day

D. Add the condition inside the command handle method instead of scheduler

Solution

1. Step 1: Understand conditional scheduling

   Laravel scheduler allows conditional scheduling by wrapping schedule calls in if statements.

2. Step 2: Use weekdays() and at() methods

   weekdays() limits to Monday-Friday, at('18:30') sets time to 6:30 PM.

3. Step 3: Apply feature flag condition

   Check config('features.enable_task') before scheduling to enable/disable task.

4. Final Answer:

   Use if (config('features.enable_task')) { $schedule->command('task:run')->weekdays()->at('18:30'); } -> Option A

5. Quick Check:

   Conditional scheduling with if + weekdays() + at() [OK]

Hint: Wrap schedule call in if to conditionally enable task [OK]

Common Mistakes:

• Scheduling unconditionally ignoring feature flag
• Using wrong cron for weekdays
• Putting condition inside command instead of scheduler