0x6d617474/wp-migrations

Migrations for WordPress plugins

1.0.0 2017-09-14 14:33 UTC

README

This package utilizes the Phinx library to bring traditional migrations to WordPress for use in plugins and themes.

Usage

Installation

composer require 0x6d617474/wp-migrations

Integrating into your plugin/theme

require_once sprintf('%s/vendor/autoload.php', $root);
$migrator = new Migrator($root, $instance, $hook);
$migrator->setNamespace('Custom\\Namespace\\Migrations');

$root is the absolute path to the root directory of your package. It should be where your composer.json file is.

$instance is an instance of your plugin/theme object. It is accessible from within the migrations via the $this->getPackage() method. If you do not use an object to contain your plugin/theme, simply pass a null value.

$hook defines the WordPress hook where the migrations will run. The recommended values are plugins_loaded for plugins and after_setup_theme for themes. Set this value to false to disable automated migrations.

Defining a namespace for your migrations helps to prevent conflicts with other packages utilizing migrations, and can be whatever makes sense for your project. By default, the namespace will be <$instance namespace>\Migrations.

Creating Migrations

Migrations can be created manually by copying the included template, or automatically using the WP-CLI command. The template file is located at vendor/0x6d617474/wp-migrations/src/migration_template.txt. Files should be placed in a migrations directory at the root of your package, and named like so: YYYYMMDDHHIISS_Your_Migration_Name. The datestamp must be unique for each migration in your package.

The included WP-CLI command wp migrations create <slug> <name> will create a new migration for you with the given name, where <slug> is the package slug.

Running Migrations

Migrations can be run automatically be defining the $hook value for the Migrator (see above). Migrations can also be run manually in your code by calling the migrate method on the $migrator object.

You can also run migrations for an individual package, or all packages utilizing the library via the wp migrations migrate <slug|--all> [--target=target] WP-CLI command. The optional target parameter specifies a target to break on, otherwise all unapplied migrations will be run.

Running Rollbacks

Rollbacks can be run manually in your code by calling the rollback method on the $migrator object.

You can also run rollbacks for an individual package, or all packages utilizing the library via the wp migrations rollback <slug|--all> [--target=target] [--date=date] WP-CLI command. The optional target parameter specifies a target to roll back to, otherwise only the latest migration will be rolled back. Similarly, the optional date parameter specifies a target date to roll back to.

Checking Status

You can view the migration status of any or all packages with the wp migrations status <slug|--all> command.

Viewing Applied Migrations

You can view the applied migrations of any package with the wp migrations show <slug> command.

Notes

Dealing with failure

Migrations that fail to complete will throw an Exception. By default, these exceptions are not caught and will halt execution. The reason for this is that usually failed migrations are a serious issue and should be dealt with immediately (graceful recovery is usually not an option).

If you'd like to handle exceptions caused by failed migrations, you can disable the automated migrate and run the migrations manually inside a try/catch block.

Multisite WordPress

Migrations are fully functional in a multisite environment, and migrations are applied in isolation for each package for each site.

If you would like to do a one-time migration for the network, the suggested approach is to define a migration that uses a sitemeta lock to check if work should be done.

public function up()
{
    $lock = '_migration_lock_Blah';
    if (get_site_option($lock, false) === false) {
        // Do the migration
        update_site_option($lock, true)
    }
}

public function down()
{
    $lock = '_migration_lock_Blah';
    if (get_site_option($lock, false) === true) {
        // Do the rollback
        update_site_option($lock, false)
    }
}

Composer Isolation

This package is compatible with the Composer Isolation package. You will likely need to update the use statement in your migrations if you apply isolation after creating a migration.

Do to WP-CLI's way of registering commands, the first package to register the migrations command will have its Command class used by all packages. This may eventually lead to incompatibilities during major version upgrades of this package, but there's not a lot we can do about it.

This only affects the WP-CLI commands. The runtime execution outside WP-CLI is fully isolated as normal.