quick_start.md

Quick Start

Reference implementation of the Forest Modelling Language 4.0 (fml40) which is explained in the KWH ForestML 4.0 white paper, currently only in German. To use the fml40 reference implementation package in your own project you need to install it using the latest wheel. To install this wheel, go to the respective directory or switch to your designated virtual environment and install the .whl file, just run

pip install https://git.rwth-aachen.de/kwh40/fml40-reference-implementation/-/jobs/artifacts/master/raw/public/ml-0.1-py3-none-any.whl?job=wheel

Features

This package provides two different modes to launch your Digital Twins:

• Launching Digital Twin quickly in persistent mode via fml40s.py. You need to register a thing identity for your Digital Twin via S³I Config REST API and prepare a respective config file which describes a ForestML 4.0 conform DT in JSON. For more details refer to the example MyDigitalTwin.json in the section Config files.
• Extending the capabilities with user defined Digital Twins, which means you can additionally define and insert a function according to ForestML 4.0 into the Digital Twin. We provide an exemplary Digital Twin built in Jupyter Notebook, refer to notebooks 08a, 08b, 08d and 08e .

Usage

Using fml40s.py

A Digital Twin can be launched in persistent mode by executing

python fml40s.py launch <CONFIG_FILE>

Config files for Digital Twin must be located in the folder configs. For more options call just run

python fml40s.py -h

Develop your Digital Twin using this package

We introduce here briefly how to develop a user-specified Digital Twin. For more details refer to the created cloud and edge Digital Twin built in Jupyter Notebook. The following steps can be only carried out after you have created the identity of your Digital Twin via Config REST API and made a respective config file. We use the config file MyDigitalTwin.json appearing in the section Config files to build a Digital Twin. Now we continue the following steps.

• Optionally set a logger using the function setup_logger. The generated log file will be then located in the folder logs.

ml.setup_logger("MyDigitalTwin")

• Set the path of config file and import it in JSON format.

config_path = os.path.abspath(os.path.join(os.path.dirname(__file__), "configs"))

dt_model = ml.load_config(config_filepath=os.path.join(config_path, "MyDigitalTwin.json"))

• Create the thing instance.

client_secret = "" #To be filled
thing = ml.create_thing(
    model=dt_model, grant_type="client_credentials", secret=client_secret,
    is_broker_rest=False, is_broker=True, is_repo=True
)

• As written in the config file, the Digital Twin has a feature named fml40::ProvidesProductionData. In the next step we extend/implement this class with our own logic.

class ProvidesProductionDataImpl(ProvidesProductionData):
    def __init__(self, name="", identifier=""):
        super(ProvidesProductionData, self).__init__(
            name=name,
            identifier=identifier)
        self.production_data_list = thing.features["ml40::ProductionData"].subFeatures["ml40::Composite"].targets

    def getProductionData(self, name):
        for key in self.production_data_list.keys():
            if key == name:
                return self.production_data_list[key].to_subthing_json()
        return {"error": "NOT FOUND"}

• Insert the class into the respective feature of your Digital Twin

ml.add_function_impl_obj(thing, ProvidesProductionDataImpl, "fml40::ProvidesProductionData")

• Launch your Digital Twin

thing.run_forever()

So far, your Digital Twin has been created. In the meantime you can establish a connection with it using S3I-B messages.

Config files

A valid configuration consists of exactly one json object. Mandatory fields of the json object are

• thingId
• policyId and
• attributes

The configuration file must be created in accordance with ForestML 4.0, refer to Cap. 7.1 of the KWH ForestML 4.0 White Paper. We provide in addition here an example JSON config file, see below.

MyDigitalTwin.json:

{
  "thingId": "s3i:id",
  "policyId": "s3i:id",
  "attributes": {
        "class": "ml40::Thing",
        "name": "my digital twin",
        "roles": [
                {
                    "class": "fml40::Harvester"
                }
            ],
        "features": [
                {
                    "class": "fml40::ProvidesProductionData"
                },
                {
                    "class": "ml40::ProductionData",
                    "subFeatures": [
                        {
                            "class": "ml40::Composite",
                            "targets": [
                                {
                                    "class": "ml40::Thing",
                                    "name": "Stammsegment 4711",
                                    "roles": [
                                        {
                                            "class": "fml40::StemSegment",
                                        }
                                    ],
                                    "features": [
                                        {
                                            "class": "ml40::Location",
                                            "latitude": 50.1231,
                                            "longitude": 6.1231
                                        },
                                        {
                                            "class": "fml40::StemSegmentProperties",
                                            "diameter": 0.4,
                                            "length": 2,
                                            "woodType": "Spruce"
                                        }
                                    ]
                                },
                                {
                                    "class": "ml40::Thing",
                                    "name": "Stammsegment 4712",
                                    "roles": [
                                        {
                                            "class": "fml40::StemSegment",
                                        }
                                    ],
                                    "features": [
                                        {
                                            "class": "ml40::Location",
                                            "latitude": 50.1231,
                                            "longitude": 6.1231
                                        },
                                        {
                                            "class": "fml40::StemSegmentProperties",
                                            "diameter": 0.6,
                                            "length": 3,
                                            "woodType": "Spruce"
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                },
                {
                    "class": "ml40::Location",
                    "longitude": 5.03424,
                    "latitude": 52.52345
                }
            ]

    }
}

Structure

Configs

This folder contains configuration files in JSON format for Digital Twins.

ml

This directory includes the implementations of the fml40 python reference implementation as described in the KWH ForestML 4.0 White Paper.

demo

Example of creating and launching a HMIm which is used to communicate with the permanent Digital Twin using S³I-B protocol.

logs

This folder is composed of the logging files of the created and launched Digital Twins.

tests

This folder contains all test scripts (currently in development).