HLO Frontend Engine

The HLO Frontend Engine is the Component of the HLO responsible for exposing an HLO REST API to the management portal. It exposes Exposes endpoints for cross-domain service LCM. It receives a TOSCA modeled service deployment request and initiates a service orchestration across aerOS domains.

Upon a create request, TOSCA yaml is parsed and its nodes are converted to NGSI-LD entities. These entities are created and pushed to domain CB. The Service entity id is pushed to HLO data aggregator.

Upon an update request, TOSCA yaml is parsed and its nodes are converted to NGSI-LD entities. Old/new entities are created/updated and pushed to domain CB. The Service entity id is pushed to HLO data aggregator.

Upon a delete request, entities are updated for service deallocation. Service id is pushed to HLO data aggregator.

HLO Frontend Engine

Prerequisities

This component requires make, helm and docker for building and installation.

Installation

Note that this component is part of HLO common deployment and used in aerOS domain installation. You can install as part of this standard installation.

For development installation :
  • git clone https://gitlab.aeros-project.eu/wp3/t3.3/hlo-frontend.git

    • cd hlo-frontend

    • python3 -m venv venv

    • pip install -r requirments

    • source venv/bin/activate

    • uvicorn main:app --reload
    • test APIs using the FastAPI swagger page, example Tosca included
      HLO-FE-EP swagger

    • or test APIs using POSTMAN collection included (HLO-FE-Engine.postman_collection.json)

    • for testing APIs either connect with MVP RedPanda broker or disable broker registration and message publishing

For isolated component installation in aerOS domain, you can use the Makefile in the repository :

Edit variables, if needed, and :

  • Build and tag docker image

make build

  • Push to aerOS repository

make push

  • Package and upload helm chart

make helm-upload

  • Deploy against cluster chosen as current k8s context

make deploy

  • All the above

make all

  • Removes docker image

make clean-build

  • Removes the helm deployment from the cluster

make clean-deploy

  • Removes all the above

make clean-all

Configuration options

The component can be configured from docker container environment variables :

  • CB_URL : Context Broker URL.

  • CB_PORT : Context Broker Port.

  • BOOTSTRAP_SERVERS : Redpanda bootstrap servers.

  • GROUP_ID : Redpanda group id.

  • AUTO_OFFSET_RESET : Auto Offset Reset option for Redpanda.

  • CONSUMER_TOPIC : The Redpanda topic used to publish to the data aggregator.

Developer guide

Communications and Interactions

As introduced before, The HLO FE EP exposes a REST API and send a trigger message to the Data Aggregator. In what follows, the concerned data definitions :

OpenAPI EP, Messages exchanged and Primitives definition

HLO FE EP openAPI

Messages exchanged

Primitives definition

 
openapi: 3.1.0
info:
  version: "1.0.0"
  title: HLO Domain Frontend API
contact:
    email: info@aeros-project.com
  license:
    name: Apache 2.0
    url: 'http://www.apache.org/licenses/LICENSE-2.0.html'
servers:
  - description: HLO Domain Frontend endpoint
     url: '{protocol}://{hostname}:{port}'
     variables:
      protocol:
        enum:
          - http
          - https
        default: https
      hostname:
        default: localhost
      port:
        default: '443'

tags:
  - name: hlo_fe

paths:
  /hlo_fe/services/{service_id}:
  post:
    tags:
      - hlo_fe
    description: Allocate a new service across domains
    operationId: allocateService
    parameters:
      - $ref: '#/components/parameters/serviceIdParameter'
    requestBody:
       description: The service TOSCA definition
      content:
        "application/x-yaml":
          schema:
            type: string
            description: "service TOSCA"
    responses:
      '200':
        description: "service allocation initiated"
      '400':
        description: "invalid service parameters"
  delete:
    tags:
      - hlo_fe
    description: Deallocate an existing service across domains
    operationId: deallocateService
    parameters:
      - $ref: '#/components/parameters/serviceIdParameter'
    responses:
      '200':
        description: "service deallocation initated"
      '404':
        $ref: "#/components/responses/ServiceNotFound"
  put:
    tags:
      - hlo_fe
    operationId: changeServiceAllocationParamters
    requestBody:
      description: The service TOSCA definition
      content:
        "application/x-yaml":
          schema:
            type: string
            description: "service TOSCA"
    parameters:
      - $ref: '#/components/parameters/serviceIdParameter'
    responses:
      '200':
        description: "service allocation parameters change initiated"
      '404':
        $ref: "#/components/responses/ServiceNotFound"
components:
  parameters:
    serviceIdParameter:
      name: 'service_id'
      in: query
      schema:
        type: string
  responses:
    ServiceNotFound:
      description: "service not found"

syntax = "proto3";

import "hlo.proto";

message HLODataAggregatorOutput {
  Service service = 1;
}

syntax = "proto3";

message Domain {
    string id = 1;
}

message Service {
    string id = 1;
}

message LowLevelOrchestrator {
    string id = 1;
    string orchestration_type = 3;
    Domain domain = 2;
}

message InfrastructureElement {
    string id = 1;
    float total_ram = 2;
    float cpu_cores = 3;
    float avg_power_consumption = 4;
    bool real_time_capable = 5;
    float current_ram = 6;
    float current_cpu_usage = 7;
    float current_power_consumption = 8;
    Domain domain = 9;
    LowLevelOrchestrator low_level_orchestrator = 10;
}

message Port {
    int32 number = 1;
}

message ServiceComponent {
    string id = 1;
    string image = 2;
    repeated Port ports = 3;
    Service service = 4;
    ServiceComponentConstraints service_component_constraints = 5;
    optional InfrastructureElement infrastructure_element = 6;
}

message ServiceComponentConstraints {
    map<string, float> constraints = 1;
}

Authors

The authors are: