README

Overview

This library ships the command migrate:safe for Laravel which executes the migrate artisan command in concurrency-safe manner using the Laravel atomic locks.

Installation

First, include the myparcelcom/concurrency-safe-migrations package in your composer dependencies:

composer require myparcelcom/concurrency-safe-migrations

Simply register the MigrateSafe command with your console Kernel:

class Kernel extends ConsoleKernel { /**  * The Artisan commands provided by your application.  *  * @var array  */ protected $commands = [ \MyParcelCom\ConcurrencySafeMigrations\Commands\Migrate::class ]; /**  * Define the application's command schedule.  *  * @param \Illuminate\Console\Scheduling\Schedule $schedule  * @return void  */ protected function schedule(Schedule $schedule) { // $schedule->command('inspire')->hourly(); } }

Configuration

All options available with the migrate command can be passed to migrate:safe too. In addition, you can configure the atomic lock settings too:

• --lock-ttl - pass custom maximum lock ttl (in seconds). The migrate:safe will automatically release the lock once done. However, it is useful to put some ttl in failure cases where the container dies and lock is not released. Default value is 60 seconds
• --cache-store - select a specific Cache store. When omitted the default cache store is selected. The cache store is required to work with atomic locks.
• --key-id - enter custom cache lock key. When omitted the APP_NAME and current application environments are used to compose a key

Background

Running migrations using migrate:safe assures that your application will not execute migrations at the same time. This could be a problem if you want to automate running migrations for your app but for whatever reason you cannot assure that the migrate command will be ran only once per deployment.

An example application is deploying a Laravel application on Kubernetes using Flux. Flux reconciles changes from Git in declarative way. Therefore, it becomes difficult to activate migrations upon deployment using a Job.

migrate:safe allows developers to attach init containers to deployment pods and only one will execute the migrations.