jgbustos/ml-rest-fastapi repository overview

⁠ml_rest_fastapi

A RESTful API to return predictions from a trained ML model, built with Python 3 and FastAPI

⁠Development set-up instructions

First, open a command line interface and clone the GitHub repo in your workspace

PS > cd $WORKSPACE_PATH$
PS > git clone https://github.com/jgbustos/ml_rest_fastapi
PS > cd ml_rest_fastapi

Create and activate a Python virtual environment, then install the required Python packages using pip

PS > virtualenv venv
PS > venv\scripts\activate.ps1
(venv) PS > pip install -r requirements.txt

Once dependencies are installed, set up the project for development

(venv) PS > pip install -e .

Finally, run the project:

(venv) PS > uvicorn ml_rest_fastapi.app:app --host 0.0.0.0 --port 8888 --reload

Open the URL http://localhost:8888/docs/⁠ with your browser and see the sample OpenAPI documentation

⁠Interfaces exposed

OpenAPI JSON available from URL http://localhost:8888/openapi.json⁠

⁠Health

These two methods are meant to be used as the liveness and readiness probes in a Kubernetes deployment:

• GET http://localhost:8888/health/live⁠ returns 200/"Live" if the service is up and running
• GET http://localhost:8888/health/ready⁠ returns 200/"Ready" or 503/"Not Ready" depending on whether the ML model has been correctly initialised or not

⁠Model

• POST http://localhost:8888/model/predict⁠ will return a prediction using the ML model. The data_point structure shows the JSON argument that must be supplied, and example values for each of the fields. The service will validate that all the mandatory values are passed. Return values are:
  • 200/Predicted value based on JSON input
  • 422/"Validation Error" if any mandatory parameter is missing or if any wrong data type (e.g. str, int, bool, datetime...) is supplied
  • 500/"Internal Server Error" as catch-all exception handler
  • 503/"Not Ready" if model is not initialised

⁠Config settings

Configuration parameters are contained in the file ml_rest_fastapi/settings.py, but they can also be overriden by setting env vars:

settings: Dict = {
    # Trained ML/AI model settings
    "TRAINED_MODEL_MODULE_NAME": "sample_model",
    # Module settings
    "DEBUG": True,
    "MULTITHREADED_INIT": True,
}

⁠Setting up the model

The trained ML model is meant to be initialised and invoked to make predictions in the context of a Python unit saved inside the directory ml_rest_fastapi/trained_model. The structure of this Python module is explained in this document⁠