Backend
Introduction
Developing a backend component for a web application depends on the specific requirements and functionalities of this application. In the scope of aerOS, that considers the aerOS Basic Services as a suite of lightweight microservices (including the potential workloads to be orchestrated in the computing continuum), it is evident that heavier computing processes (e.g., data processing) must be removed from the unique web application that aims to act as the management entry point to the continuum.
Thus, removing this logic from the frontend component of the portal allows to develop the frontend to just react to user actions and obtain the needed data in the expected format to be then efficiently interpreted, as well as avoiding some security issues like the well-known CORS. Therefore, the backend component acts as a middleware between the web page and third-party APIs
Finally, although this component can work as an independent REST API, it is intended to be used as the backend of the aerOS Management Portal Frontend.
User guide
The backend of the Management Portal an work as an independent REST API, but it has been designed to be deployed along with the frontend of the portal.
Prerequisities
This aerOS Basic Services are needed to cover all the functionalities provided by the backend:
Keycloak
OpenLDAP
Orion-LD
Entrypoint Balancer & aerOS orchestrator
Configuration options
This backend can be configured by using these environment variables:
LOG_LEVEL: logging level of the application itself (ERROR, WARN, INFO, DEBUG, or TRACE).
LDAP_LOG_LEVEL: logging level of LDAP modules of the application (it includes the Spring Data LDAP 3 framework).
SECURITY_LOG_LEVEL: logging level of the Spring Security 6 framework (ERROR, WARN, INFO, DEBUG, or TRACE).
ORION_URL: URL of the Orion-LD instance (including the path to its entities endpoint) of the entrypoint domain.
HLO_FE_URL: full URL of the REST API (FE endpoint) of the of the aerOS HLO’s Storage Engine component.
ENTRYPOINT_BALANCER_URL: full URL of the Entrypoint Balancer.
KEYCLOAK_URL: URL of the Keycloak instance of the entrypoint domain.
KEYCLOAK_REALM: realm of the Keycloak instance of the entrypoint domain.
LDAP_URL: URL of the LDAP instance of the entrypoint domain.
LDAP_USERNAME: username of the LDAP instance of the entrypoint domain.
LDAP_PASSWORD: password of the LDAP instance of the entrypoint domain.
Developer guide
The Backend of the aerOS Management Portal has been developed a Spring Framework 6 application, starting the project with Spring Boot 3 and using some complementary libraries such as Spring Security, Spring Cloud and Spring LDAP.
Minimum prerequirements for the local development machine:
The recommended IDE to develop this component is IntelliJ IDEA but other alternatives such as Eclipse Java IDE and VSCode can be used as well.
Now, the application can be run using the selected IDE. It will run by default in the port 8080.
Finally, the Spring application can be configured through the modification of the src/main/resources/application.properties file:
# Logging
logging.level.eu.aerosproject=${LOG_LEVEL:INFO}
logging.level.org.springframework.ldap=${LDAP_LOG_LEVEL:INFO}
logging.level.org.springframework.security=${SECURITY_LOG_LEVEL:INFO}
# logging.level.org.springframework.web.socket=${WEBSOCKET_LOG_LEVEL:INFO} # only for STOMP WebSockets
# aerOS configuration
aeros.entrypoint-balancer=${ENTRYPOINT_BALANCER_URL:http://entrypoint-balancer.default.svc.cluster.local:8080}
aeros.hlo-fe=${HLO_FE_URL:http://hlo-fe-service.default.svc.cluster.local:8081}
aeros.orion-ld=${ORION_URL:http://orion-ld-broker.default.svc.cluster.local:1026/ngsi-ld/v1/entities}
# External LDAP directory configuration
spring.ldap.urls=${LDAP_URL:ldap://openldap.default.svc.cluster.local:389}
spring.ldap.username=${LDAP_USERNAME:cn=admin,dc=example,dc=org}
spring.ldap.password=${LDAP_PASSWORD:<Password>}
Packaging into a JAR file
This application can be packaged into a Java JAR file using Maven. This JAR file will be created inside the target folder named as management-portal-backend-{POM-application-version}.jar, for instance, management-portal-backend-1.1.0.jar. The application version is specified in the line 13 of the pom.xml file.
In order to package the application into a JAR file, run:
mvn clean compile package
Build a container image
First, package the application into a JAR file. Then, use the included Dockerfile to build the container image:
docker build -t registry.gitlab.aeros-project.eu/aeros-public/common-deployments/management-portal/backend:<app-version> --build-arg APP_VERSION=<app-version> .
For instance:
docker build -t registry.gitlab.aeros-project.eu/aeros-public/common-deployments/management-portal/backend:1.1.0 --build-arg APP_VERSION=1.1.0 .