As explained in nelmio/alice documentation, you have three ways to declare custom data provider. To use Custom Faker Provider classes you will have to declare them as services:

<?php

namespace AppBundle\DataFixtures\Faker\Provider;

class FooProvider
{
    public static function foo($str)
    {
        return 'foo'.$str;
    }
}

Then declare it as a service with the hautelook_alice.faker.provider tag:

# app/config/services.yml

services:
    faker.provider.foo:
        class: AppBundle\DataFixtures\Faker\Provider\FooProvider
        tags: [ { name: hautelook_alice.faker.provider } ]

That's it! You can now use it in your fixtures:

# src/AppBundle/DataFixtures/ORM/dummy.yml

AppBundle\Entity\Dummy:
    brand{1..10}:
        name: <foo('a string')>

Warning: rely on Custom Faker Providers helpers to generate random data (most of them are static).

Sometimes, your Provider needs to extend the Faker Base Provider or one of it's children. The issue is it needs a Faker\Generator instance. AliceBundle provides a faker generator hautelook_alice.faker configured with the bundle parameters and with all the registered providers. You must not use this one for your providers: as this generator requires all providers, if your provider requires this generator this will result in a circular references. In such cases, you should use your own Faker generator:

# app/config/services.yml
services:
    hautelook_alice.bare_faker:
        class: Faker\Generator
        factory: [ Faker\Factory, create ]
        lazy: true
        arguments:
            - %hautelook_alice.locale%
        calls:
            - [ seed, [ %hautelook_alice.seed% ] ]

Example:

<?php

namespace AppBundle\DataFixtures\Faker\Provider;

use Faker\Provider\Base as BaseProvider;

class FooProvider extends BaseProvider;
{
    public static function foo($str)
    {
        return 'foo'.$str;
    }
}

# app/config/services.yml

services:
    faker.provider.foo:
        class: AppBundle\DataFixtures\Faker\Provider\FooProvider
        arguments: [ @hautelook_alice.bare_faker ]
        tags: [ { name: hautelook_alice.faker.provider } ]

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