chore: Update README.md for backend development.

README.md

@@ -8,10 +8,9 @@ Look at the [contribution guide](CONTRIBUTING.md).
 
 ## Install development environment
 
-### Install node and npm
-install nvm
+- Install `node` and `npm`
 
-go to :
+Installation via `nvm` is recommended for easier control of installed version:
 https://github.com/creationix/nvm
 
 ```sh
@@ -19,33 +18,51 @@ nvm install 10.13.0
 nvm use v10.13.0
 ```
 
-### Install Angular CLI
+- Install Angular CLI
 
 ```sh
 npm install -g @angular/cli@7.0.6
 ```
 
-### Install JS dependencies
+- Install JS dependencies
 
 ```sh
 cd frontend
 npm install
 ```
 
-### Install Java JDK8
+- Install latest Java JDK8
 
-See instructions for your operating system
+See latest instructions for your operating system.
+
+- (Optional) Install `docker` and `docker-compose`
+
+If you want to run an Elasticsearch and Kibana instance on your machine.
+You can use your favorite package manager for that
 
 
 ## Run backend development server
 
-If you just need access to API (to run the Angular serve on top) without the frontend interface, you can run:
+First make sure you have access to an Elasticsearch HTTP API server on `http://127.0.0.1:9200` (either via ssh tunneling or by running a local server).
+
+If you want to run an Elasticsearch server on your development machine you can use the `docker`/`docker-compose` configuration like so:
+
+```sh
+docker-compose up
+```
+
+> This will launch an Elasticsearch server (with port forwarding `9200` and `9300`) and a Kibana server (with port forwarding `5601`)
+
+> **Warning**: This repository does not automatically index data into Elasticsearch, you need to prepare your indices beforehand.
+
+
+If you just need access to API (to run the `ng serve` on top of it), you can run:
 
 ```sh
 ./gradlew bootRun
 ```
 
-Otherwise, for the complete server (backend API + frontend interface), you can run:
+Otherwise, for the complete server (backend APIs + frontend interface), you can run:
 
 ```sh
 ./gradlew assemble && java -jar backend/build/libs/gpds.jar
@@ -78,3 +95,33 @@ If you want to run the GitLab CI locally, you have to follow this steps:
 ```sh
 gitlab-runner exec docker test 
 ```
+
+
+## Spring Cloud config
+
+On bootstrap, the application will try to connect to a remote Spring Cloud config server
+to fetch its configuration.
+The details of this remote server are filled in the `bootstrap.yml` file.
+By default, it tries to connect to the remote server on http://localhost:8888
+but it can of course be changed, or even configured via the `SPRING_CONFIG_URI` environment variable.
+
+It will try to fetch the configuration for the application name `rare`, and the default profile.
+If such a configuration is not found, it will then fallback to the local `application.yml` properties.
+To avoid running the Spring Cloud config server every time when developing the application,
+all the properties are still available in `application.yml` even if they are configured on the remote Spring Cloud server as well.
+
+> **TODO**: Create a sping cloud configuration git repository and update the following section:
+
+> If you want to use the Spring Cloud config app locally,
+see https://forgemia.inra.fr/urgi-is/data-discovery-config
+
+> The configuration is currently only read on startup,
+meaning the application has to be reboot if the configuration is changed on the Spring Cloud server.
+For a dynamic reload without restarting the application,
+see http://cloud.spring.io/spring-cloud-static/Finchley.SR1/single/spring-cloud.html#refresh-scope
+to check what has to be changed.
+
+> In case of testing configuration from the config server, one may use a dedicated branch on `data-discovery-config` project
+and append the `--spring.cloud.config.label=<branch name to test>` parameter when starting the application's executable jar.
+More info on how pass a parameter to a Spring Boot app:
+https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html#boot-features-external-config