event-store

Simple EventStore implementation package for Laravel using MySQL.

Installation

To start using this package, install it with composer:

composer require maslauskas/event-store

Publishing config and migrations:

php artisan vendor:publish --provider=Maslauskas\EventStore\EventStoreServiceProvider

This package uses Laravel's package auto-discovery feature, so there is no need to modify your config/app.php file.

Configuration

Event Store logs are saved to your main database by default, but it is recommended to use a dedicated MySQL database for it. Once you create the database, make sure to set Event Store to use it:

First, add a dedicated connection to your config/database.php file:

'connections' => [

        /*
        ...
        */

        'eventstore' => [
            'driver' => 'mysql',
            'host' => env('EVENT_STORE_HOST', 'localhost'),
            'port' => env('EVENT_STORE_PORT', '3306'),
            'database' => env('EVENT_STORE_DATABASE', 'event_store'),
            'username' => env('EVENT_STORE_USERNAME', 'root'),
            'password' => env('EVENT_STORE_PASSWORD', 'root'),
            'unix_socket' => env('DB_SOCKET', ''),
            'charset' => 'utf8mb4',
            'collation' => 'utf8mb4_unicode_ci',
            'prefix' => '',
            'strict' => true,
            'engine' => null,
        ],

        /*
        ...
        */
]

Next, add required environment variables to your .env file:

EVENT_STORE_CONNECTION="eventstore"
EVENT_STORE_DATABASE="your_event_store_database_name"
EVENT_STORE_TABLE="your_event_store_table_name"
EVENT_STORE_USERNAME="your_event_store_user_name"
EVENT_STORE_PASSWORD="your_event_store_user_password"

It is recommended to create a separate user for event store database, and remove UPDATE, DELETE, DROP permissions, to make sure your event store is append-only.

Next, run the migration to create default event store table:

php artisan migrate

Usage

To start logging your events, append this line to your code where you wish the event to be logged:

EventStore::add('event_name', $data);

Or using the eventstore helper function, which is just a wrapper for the facade:

eventstore()->add('event_name', $data);

the add() method accepts four arguments:

• $event_type: name of your event, e.g. user_created, email_sent, order_shipped, etc.
• $payload: array of values to record. e.g. for user_created event, you can pass the array of attributes that this user was created with.
• $target_id: (optional) ID of target model in your database. E.g., for email_sent event, you can pass user_id as $target_id. This helps in the future when you wish to fetch all events related to a particular user.
• $before: (optional) array of values that were changed. E.g. for user_updated event, you may pass $user->toArray() to record attributes that were changed and their values before the change. Note: the add() method automatically filters out only those keys that exist in $payload parameter to avoid unnecessary overhead.

Sometimes, certain events occur much more frequently than others, e.g. user_created and user_logged_in. To help with query performance, you can separate certain events to their dedicated tables by changing the streams array in config/eventstore.php file:

'streams' => [
    'user_login_stream' => [
        'user_logged_in',
    ]
]

This will automatically create a dedicated user_login_stream table in your event store database when you try to add user_logged_in event. All events that are not defined in this array will be saved in the default event store table.

Extra methods

query()

Returns Illuminate\Database\Eloquent\Builder instance so you can perform any query on event store tables.

get()

Gets all events from the default event store table. Returns a collection.

get($event_name)

Gets all events of specific type from event store table. Automatically determines which table to search in. Returns a collection.

stream($stream_name)

Sets dedicated table and returns Illuminate\Database\Eloquent\Builder instance so you can perform any query on event store tables.

Exception handling

By default, EventStore suppresses any exceptions that occur during add() method call. You can disable this by changing throw_exceptions setting in config/eventstore.php:

'throw_exceptions' => true,

Testing

Run the tests with

vendor/bin/phpunit