Scheduler with cron in Laravel - Mini Project: Build & Apply

Scheduler with cron in Laravel

📖 Scenario: You are building a Laravel application that needs to run a task every minute to clean up old records. You will set up a scheduler using Laravel's task scheduling system and configure a cron job to trigger it.

🎯 Goal: Create a Laravel command, schedule it to run every minute using Laravel's scheduler, and configure the cron entry to run the scheduler.

📋 What You'll Learn

Create a Laravel command named CleanupOldRecords

Schedule the command to run every minute in app/Console/Kernel.php

Add the cron entry to run Laravel's scheduler every minute

💡 Why This Matters

🌍 Real World

Many web applications need to perform regular maintenance tasks like cleaning old data or sending notifications. Laravel's scheduler with cron makes this easy and reliable.

💼 Career

Understanding Laravel's task scheduling and cron integration is essential for backend developers working with Laravel to automate repetitive tasks efficiently.

1

Create the Laravel command CleanupOldRecords

Run the artisan command to create a new command named CleanupOldRecords inside the app/Console/Commands directory.

Laravel

# Run the artisan command to create CleanupOldRecords
# Your code here

Hint

Use php artisan make:command CleanupOldRecords to create the command.

2

Schedule the CleanupOldRecords command every minute

Open app/Console/Kernel.php and add the line $schedule->command('cleanup:oldrecords')->everyMinute(); inside the schedule method.

Laravel

protected function schedule(Schedule $schedule)
{
    // Add the command schedule here
    # Your code here
}

Hint

Inside the schedule method, use $schedule->command('cleanup:oldrecords')->everyMinute();.

3

Add the cron entry to run Laravel scheduler every minute

Add the following cron entry to your server's crontab: * * * * * cd /path-to-your-project && php artisan schedule:run >> /dev/null 2>&1. Replace /path-to-your-project with your Laravel project path.

Laravel

# Add this cron entry to your crontab
# * * * * * cd /path-to-your-project && php artisan schedule:run >> /dev/null 2>&1
# Your code here

Hint

Use crontab -e to edit the cron jobs and add the line to run Laravel's scheduler every minute.

4

Complete the CleanupOldRecords command handle method

Open app/Console/Commands/CleanupOldRecords.php and add a handle method that deletes records older than 30 days from the old_records table using Eloquent's whereDate and delete methods.

Laravel

public function handle()
{
    // Delete records older than 30 days from old_records table
    # Your code here
}

Hint

Use Carbon to get the date 30 days ago and delete records older than that from the old_records table.

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