This repository is taken and adapted from label-studio-ml-backend.

What is the Label Studio ML backend?

The Label Studio ML backend is an SDK that lets you wrap your machine learning code and turn it into a web server. The web server can be connected to a running Label Studio instance to automate labeling tasks.

If you just need to load static pre-annotated data into Label Studio, running an ML backend might be overkill for you. Instead, you can import preannotated data.

Run the ML Backend

1. Installation

Download and install label-studio-ml from the repository:

git clone https://github.com/redur/label-studio-ml-backend.git

The code comes with two different ml-models that have their own respective endpoint. The directory structure for both models are the same. Information regarding the respective ML Models are found in their readmes located in the respective directories.

2. Prepare the services

The ML Models require the data available in their respective container. Therefore we need to ensure that the right directories are mounted. (Note: this should be deprecated once we move to S3 datastorage.).

The stratigraphy-ml-backend needs the original pdf files used for the stratigraphy algorithm. Create a directory containing the files and add it in the docker-compose.yml for the service stratigraphy-ml-backend.

The text-extractor service requires the png files of the extracted layers from the stratigraphy algorithm. Place the corresponding files in a directory and mount it in the docker-compose.yml for the text-extractor service.

3. Run the services

Run docker-compose build and docker-compose up to run both services. Two endpoints will be created. The stratigraphy-ml-backend will listen on port 9090 and text-extractor will listen on port 9095. You can now go to your label-studio front end and add the ML Backends in the UI. Note: You will have to find the IP adress of the docker containers first. You can find them in the logs. If you run them locally, it is your localhost.

Extend / Adjust the Backend

1. File Structure

You can go to the label_studio_ml/MODEL_NAME directory and modify the code to implement your own inference logic. The directory structure should look like this:

MODEL_NAME/
├── Dockerfile
├── model.py
├── _wsgi.py
├── README.md
└── requirements.txt

Dockefile is used to run the ML backend with Docker. model.py is the main file where you can implement your own training and inference logic. _wsgi.py is a helper file that is used to run the ML backend with Docker (you don't need to modify it) README.md is a readme file with instructions on how to run the ML backend. requirements.txt is a file with Python dependencies.

2. Implement prediction logic

In your model directory, locate the model.py file (for example, my_ml_backend/model.py).

The model.py file contains a class declaration inherited from LabelStudioMLBase. This class provides wrappers for the API methods that are used by Label Studio to communicate with the ML backend. You can override the methods to implement your own logic:

def predict(self, tasks, context, **kwargs):
    """Make predictions for the tasks."""
    return predictions

The predict method is used to make predictions for the tasks. It uses the following:

• tasks: Label Studio tasks in JSON format
• context: Label Studio context in JSON format - for interactive labeling scenario
• predictions: Predictions array in JSON format

Once you implement the predict method, you can see predictions from the connected ML backend in Label Studio.

3. Implement training logic (optional)

You can also implement the fit method to train your model. The fit method is typically used to train the model on the labeled data, although it can be used for any arbitrary operations that require data persistence (for example, storing labeled data in database, saving model weights, keeping LLM prompts history, etc). By default, the fit method is called at any data action in Label Studio, like creating a new task or updating annotations. You can modify this behavior in Label Studio > Settings > Webhooks.

To implement the fit method, you need to override the fit method in your model.py file:

def fit(self, event, data, **kwargs):
    """Train the model on the labeled data."""
    old_model = self.get('old_model')
    # write your logic to update the model
    self.set('new_model', new_model)

with

• event: event type can be 'ANNOTATION_CREATED', 'ANNOTATION_UPDATED', etc.
• data the payload received from the event (check more on Webhook event reference)

Additionally, there are two helper methods that you can use to store and retrieve data from the ML backend:

• self.set(key, value) - store data in the ML backend
• self.get(key) - retrieve data from the ML backend

Both methods can be used elsewhere in the ML backend code, for example, in the predict method to get the new model weights.

Other methods and parameters

Other methods and parameters are available within the LabelStudioMLBase class:

• self.label_config - returns the Label Studio labeling config as XML string.
• self.parsed_label_config - returns the Label Studio labeling config as JSON.
• self.model_version - returns the current model version.
• self.get_local_path(url, task_id) - this helper function is used to download and cache an url that is typically stored in task['data'], and to return the local path to it. The URL can be: LS uploaded file, LS Local Storage, LS Cloud Storage or any other http(s) URL.

Run without Docker

To run without docker (for example, for debugging purposes), you can use the following command: (make sure to install the dependencies beforehand).

label-studio-ml start my_ml_backend

Test your ML backend

Modify the my_ml_backend/test_api.py to ensure that your ML backend works as expected.

Modify the port

To modify the port, use the -p parameter:

label-studio-ml start my_ml_backend -p 9091

Deploy your ML backend to GCP

Before you start:

1. Install gcloud
2. Init billing for account if it's not activated
3. Init gcloud, type the following commands and login in browser:

gcloud auth login

4. Activate your Cloud Build API
5. Find your GCP project ID
6. (Optional) Add GCP_REGION with your default region to your ENV variables

To start deployment:

1. Create your own ML backend
2. Start deployment to GCP:

label-studio-ml deploy gcp {ml-backend-local-dir} \
--from={model-python-script} \
--gcp-project-id {gcp-project-id} \
--label-studio-host {https://app.heartex.com} \
--label-studio-api-key {YOUR-LABEL-STUDIO-API-KEY}

3. After label studio deploys the model - you will get model endpoint in console.

Troubleshooting

File not found

Make sure the right directories are mounted to your docker containers.

Troubleshooting Pip Cache Reset in Docker Images

Sometimes, you want to reset the pip cache to ensure that the latest versions of the dependencies are installed. For example, Label Studio ML Backend library is used as label-studio-ml @ git+https://github.com/HumanSignal/label-studio-ml-backend.git in requirements.txt. Let's assume that it is updated, and you want to jump on the latest version in your docker image with the ML model.

You can rebuild a docker image from scratch with the following command:

docker compose build --no-cache

Development Roadmap

• Move files to S3
• Make it possible to upload files --> should be placed in a respective folder on S3