Documentation: how define proto and service in a shared library

docs/how-to/define-proto-and-service-in-a-shared-library.rst

@@ -1,13 +1,44 @@
 .. _define-proto-and-service-in-a-shared-library:
 
+
 Define proto and service in a shared library
 =============================================
 
 Description
 -----------
+The objective of this documentation is to demonstrate how to create a service within a library and share it among various applications.
+
+Django, by definition, is a modular system that allows you to divide a project into several applications. This functionality is important to us, 
+this is why in django-socio-grpc we left the possibility for users to maintain this behavior.
+
+This behavior can lead us to have services on an external application or library that we wish to reuse in another. Follow
+this guide to importing external services to your application with django-socio-grpc.
 
 Usage
 -----
+To define a shared service in a library that can be reused across different projects, you will first need to create your service with its functions. 
+To ensure the service can be shared, you must use the `to_root_grpc` argument in the handler and set it to "True," 
+as shown in the example below.
+
+This argument allows the proto generation to create a .proto and pb2 file in a special folder at the root of the library, with the path defined 
+in grpc_settings.ROOT_GRPC_FOLDER from django-socio-grpc. (by default, the name of this folder will be grpc_folder at the root of your application)
+
+:ref:`settings<_root_grpc_folder_settings>`.
 
 Example
 -------
+
+In this specific case, my_external_library is an external library.
+
+.. code-block:: python
+
+  from my_external_library import ExternalService
+
+    def handler(server):
+        registry = AppHandlerRegistry(
+            app_name="my_external_library", server=server, to_root_grpc=True
+        )
+        app_registry.register(ExternalService)
+
+By defining here, "to_root_grpc=True", when you generate your protos, they will be added in a folder with the name and path defined in your 
+setting grpc_settings.ROOT_GRPC_FOLDER. (by default grpc_folder at the root of your application).

docs/settings.rst

@@ -206,6 +206,8 @@ For instance, you could have a generic logging middleware that logs every gRPC r
 ROOT_GRPC_FOLDER
 ^^^^^^^^^^^^^^^^
 
+.. _root_grpc_folder_settings:
+
 This setting specifies the root directory name where all the
 generated proto files of external services are outputted.
 More details about