Asset Connector MQTT Python

This project provides a FastAPI-based connector for interfacing with assets using AID (Asset Interface Description). It allows dynamic configuration and value retrieval for assets described by AID submodels.

Features

• Set configuration for assets via /add-config endpoint
• Retrieve values from assets via /get-value endpoint
• Write values at assets via /set-value endpoint
• Thread-safe storage of asset connections

Requirements

• Python 3.11+

Installation

1. Clone the repository:

   git clone <repo-url>
   cd asset-connector

2. Install dependencies:

   pip install -r requirements.txt

Start

1. Start the FastAPI server (from the base directory asset-connector):

   python cli.py

2. Or use docker

   docker build -t localhost/asset-connector:latest . && docker run -p 8000:8000 localhost/asset-connector:latest

Usage

1. Use the /add-config endpoint to configure an asset. A Connector responsible for this asset will be initialized based on the details in the AID submodel. The AID JSON must be included in the POST body content like in the following definition:

   {
      "Aid": {
         <AID Submodel JSON>
      }
   }

   Example:

   {
      "Aid": {
         "idShort": "AssetInterfacesDescription",
         "description": [
            {
            "language": "en",
            "text": "AID Sample"
            }
         ],
         "id": "https://fluid40.de/ids/sm/4757_4856_8464_1441",
         // ...
      }
   }

2. Use the /get-value endpoint to retrieve values from the asset using a specific AID configuration. A Connector must be initialized with /add-config first before you can use it! The POST body content must contain the ModelReference to one of the properties (endpoints) defined in the AID.

   {
      "Reference": {
         <ModelReference JSON>
      }
   }

   Example:

   {
      "Reference": {
         "type": "ModelReference",
         "keys": [
            {
               "type": "Submodel",
               "value": "https://fluid40.de/ids/sm/4757_4856_8464_1441"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "Interface_MQTT"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "InteractionMetadata"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "properties"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "axes_position"
            }
         ]
      }
   }

3. Use the /set-value endpoint to set values at the asset using a specific AID configuration. A Connector must be initialized with /add-config first before you can use it! The POST body content must contain the ModelReference to one of the properties (endpoints) defined in the AID and the new data.

   {
      "Reference": {
         <ModelReference JSON>
      },
      "Value": "..."
   }

   Example:

   {
      "Reference": {
         "type": "ModelReference",
         "keys": [
            {
               "type": "Submodel",
               "value": "https://fluid40.de/ids/sm/4757_4856_8464_1441"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "Interface_MQTT"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "InteractionMetadata"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "properties"
            },
            {
               "type": "SubmodelElementCollection",
               "value": "axes_position"
            }
         ]
      },
      "Value": "new-value"
   }

‍[!TIP] You can also discover the endpoints and request body schemata using Swagger by adding /docs to the base url, e.g., http://127.0.0.1:8000/docs.

‍[!TIP] The provided AID Submodels serve as the only means of configuration for the Asset Connector. You thus have to make sure that the asset endpoints are reachable from this microservice. If the service runs containerized, having a base address like http://localhost in an AID will most probably fail since it points to the container itself.

Project Structure

• main.py: FastAPI application entry point
• core/: Core logic for AID parsing and reference resolution
• models/: Data models for payloads and responses
• requests/: Example JSON payloads
• mqtt, opc_ua, http_connector: Protocol-specific implementations of the communication logic

License

MIT