Some useful notes about using FOSElasticaBundle in symfony

The notes below are for those who use FOSElasticaBundle in their projects. You'll find an example for each points below in this blog.

Notes

• If you want to apply a condition for selecting data from database before populating elasticsearch index, you can use provider.query_builder_method method which is a custom built method in a repository.


• If you can, don't index everything you have in database. Use provider.query_builder_method option to manually select specific fields in database to populate elasticsearch index. The smaller the index size, the faster the query.


• Use native @fos_elastica.index.post_index[indexName].post[type] (use Elastica\Type;) dependency injection service for elasticsearch processes rather than @fos_elastica.finder.post_index[indexName].post[type] (use FOS\ElasticaBundle\Finder\TransformedFinder;) dependency injection service. Using native 'index' option will give you faster result and more options to use while querying the index. In the case of 'finder' option, you might end up using third party libraries like Pagerfanta that adds overhead to process behind the scene while querying the index.


• If you want to prevent elasticsearch index being automatically updated behind the scene after carrying out a database CRUD like operation, you can manually disable this behaviour by setting listener.[insert|update|delete] options to 'false' individually or all.


• If you want to prevent elasticsearch index being automatically updated and do it yourself manually behind the scene after carrying out a database CRUD like operation, you can either create a custom event subscriber or a listener to do all that for you. I suggest use of a listener.


• If you want to create an elasticsearch index manually to manipulate records that come from database such as changing default field values, adding a non existing key-value pair to the index so on, you can use persistence.model_to_elastica_transformer option.


• If you don't have a database to provide data to populate your elasticsearch index then you can use another source to fetch data from such as an array, text file etc. For that, you can create a custom provider class and use it in provider.service option.

Example config

For more information and options available, check Configuration.php.

Bare minimum

persistence:
    driver: orm
    model: Your/AppBundle/Entity/User
    finder: ~
    provider: ~
    listener: ~

Explanation

persistence:
    driver: The driver you are using.
    model: The entity class that you want to create an index from.
    finder: Used to query ES finder. No need to touch this.
    provider: Used to create a custom repository QueryBuilder (query_builder_method) that manually selects records from the DB to populate the index from. Or, we can populate index with the data coming from somewhere else rather than the database by using a custom provider class (service).
    listener: Define how do you wish to update elasticsearch index after CRUD operations in DB.
    model_to_elastica_transformer: Used to create a custom class which is used to populate/manipulate ES index creation.