Djangoes provides only simple and basic backends: they use transport and connection classes provided by default by elastichsearch-py. They aim to provide a set of methods easy to use, as they will automatically use the configured indices.
Each backend uses one of the connection class provided by elastichsearch-py:
To configure a backend, simply add the expected keyword arguments in the PARAMS key of the connection configuration dict.
All connection classes used by these backends are describe in the official documentation of elasticsearch-py.
The backend djangoes.backends.elasticsearch.SimpleHttpBackend uses the connection class used by default by the Transport class: elasticsearch.connection.http_urllib3.Urllib3HttpConnection.
Each query will be performed with an HTTP request, using the urllib3 library.
The backend djangoes.backends.elasticsearch.SimpleRequestsHttpBackend uses the connection class elasticsearch.connection.http_requests.RequestsHttpConnection.
Each query will be performed with an HTTP request, using the requests library (also known as “HTTP for human”).
The backend djangoes.backends.elasticsearch.SimpleThriftBackend uses the connection class elasticsearch.connection.thrift.ThriftConnection.
Each query will be performed using the Thrift protocol.
The backend djangoes.backends.elasticsearch.SimpleMemcachedBackend uses the connection class elasticsearch.connection.memcached.MemcachedConnection.
Each query will be performed using memcached.
Create a custom backend for your application is as easy as subclassing the abstract class, and implement your own methods.
The backend interface is not yet stable. It should be, as soon as possible, but not yet. So don’t rush in the code without a look at the current available backend classes.
A backend is expected to subclass the djangoes.backends.abstracts.Base class. Then, its __init__ method is expected to accept these three parameters:
- alias: the connection’s alias. It is the key used in ES_SERVERS to configure the connection using this backend.
- server: the configuration dict of the connection, as found in ES_SERVERS, where all undefined values are replaced by the defaults.
- indices: the list of configuration dict of the connection’s indices, as found in ES_INDICES, where all undefined values are replaced by the defaults.
Extend ElasticSearch backends¶
The built-in djangoes backends are all based on an abstract class: djangoes.backends.elasticsearch.BaseElasticsearchBackend. This class conveniently subclass the abstract base class, and gives two entry point to override its behavior:
- transport_class: the transport class used to configure the elasticsearch-py client.
- connection_class: the connection class used by the transport class.
If you are already familiar with the transport class and the connection classes described in the elasticsearch-py library documentation, you should not have any issue with finding your way.