AEF_GW (API Exposer Function Gateway)

AEF_GW is a gateway component designed to bridge legacy systems with the Common API Framework (CAPIF). It simplifies the integration process, enabling legacy systems to interact seamlessly with CAPIF and adopt modern APIs without extensive modifications.

The component leverages the Opencapif_sdk to manage the interactions between systems and CAPIF effectively.

Overview of AEF_GW

AEF_GW acts as an intermediary, translating and exposing APIs from legacy systems in a format compatible with CAPIF. It manages communication between the Southbound interface (legacy systems) and the Northbound interface (CAPIF), ensuring secure, reliable, and flexible API interaction.

Getting Started

Prerequisites

To use AEF_GW, you need:

1. A registered user account in the CAPIF instance.
   • Contact your CAPIF administrator to obtain the necessary credentials (CAPIF username and password).
2. The following software dependencies:
   • Python 3.12+
   • pipenv or virtualenv for managing Python environments.

Installation Steps

1. Set up a virtual environment:

   python -m venv venv
   source venv/bin/activate  # On Windows, use `venv\Scripts\activate`
   

2. Install AEF_GW:

   pip install aef_gw
   

Configuration

AEF_GW requires two YAML configuration files:

1. Northbound (northbound.yaml): Defines interaction with CAPIF.
2. Southbound (southbound.yaml): Specifies communication with legacy systems.

1. Northbound Configuration

The northbound.yaml file defines the integration with CAPIF, including API specifications and OpenCapif SDK settings.

Key Fields

• ip: The IP address to expose.
• port: The port to expose.
• opencapif_sdk_configuration: Configures the OpenCapif SDK.
• openapi: Specifies the API exposed to CAPIF.

OpenCapif SDK Configuration

Here are the required fields for the opencapif_sdk_configuration:

• capif_host: CAPIF server domain.
• register_host: Registration server domain.
• capif_https_port: CAPIF server HTTPS port.
• capif_register_port: Registration server port.
• capif_username: CAPIF username.
• capif_password: CAPIF password.
• debug_mode: Enables detailed logs (True or False).

Example of a provider's certificate generation settings:

provider:
  cert_generation:
    csr_common_name: "example"
    csr_organizational_unit: "development"
    csr_organization: "ACME"
    csr_locality: "New York"
    csr_state_or_province_name: "NY"
    csr_country_name: "US"
    csr_email_address: "example@example.com"

OpenAPI Configuration

The openapi field must adhere to the OpenAPI Specification. Use tools like Swagger Editor to validate the configuration.

Example Configuration:

openapi:
  openapi: 3.0.0
  info:
    title: My API
    description: Example API for demonstration
    version: 1.0.0
  paths:
    /greet:
      get:
        summary: Say hello
        description: Returns a greeting message.
        responses:
          '200':
            description: Success
            content:
              application/json:
                schema:
                  type: object
                  properties:
                    message:
                      type: string
                      example: "Hello!"

2. Southbound Configuration

The southbound.yaml file defines how AEF_GW interacts with legacy systems.

Key Fields

• ip: The IP address to expose.
• port: The port to expose.
• type: The type of endpoint (REST is currently supported).
• authentication_method: Authentication options:
  • HTTP Basic Authentication
  • JWT Bearer Token
• credentials:
  • For HTTP Basic Authentication:

    username: "admin"
    password: "password123"
    

  • For JWT Bearer Token:

    jwt: "your-token"
    

• paths: Maps Northbound API paths to Southbound API paths, including HTTP methods and parameter mappings.

Example Configuration:

southbound:
  ip: 0.0.0.0
  port: 8000
  type: REST
  authentication_method: "JWT Bearer Token"
  credentials:
    jwt: "example-token"
  paths:
    - northbound_path: "/greet"
      southbound_path: "/hello"
      method: GET
    - northbound_path: "/greet/{name}"
      southbound_path: "/hello/{person}"
      method: GET
      parameters:
        - name: person

Usage

1. Place the northbound.yaml and southbound.yaml configuration files in a working directory.
2. Use the following commands to interact with AEF_GW:

• Start the gateway (first-time setup):

  cd ./directory/with/configuration/files
  aef_gw start
  

• Run the gateway (after initial setup):

  cd ./directory/with/configuration/files
  aef_gw run
  

• Remove the gateway interface:

  cd ./directory/with/configuration/files
  aef_gw remove
  

Adding a New Endpoint

To add a new API endpoint:

1. Update northbound.yaml to define the endpoint.
2. Map the corresponding route in southbound.yaml.
3. Start the gateway with:

   cd ./directory/with/configuration/files
   aef_gw start
   

Refreshing the Southbound JWT Token

To refresh the Southbound JWT token:

1. Update the jwt field in the southbound.yaml file.
2. Apply the changes with:

   cd ./directory/with/configuration/files
   aef_gw refresh
   

This ensures the new token is applied seamlessly.