flask_model_hosting_server_with_health_and_predict_endpoints.py

1import os
2from flask import Flask, request, jsonify
3
4app = Flask(__name__)
5
6# The standard requires a health check endpoint at /health
7@app.route('/health', methods=['GET'])
8def health_check():
9    # A standard health check returns 200 OK
10    return jsonify({"status": "healthy"}), 200
11
12# The standard requires a prediction endpoint at /predict
13@app.route('/predict', methods=['POST'])
14def predict():
15    try:
16        # Standard expects JSON input
17        data = request.get_json()
18        
19        if not data or 'instances' not in data:
20            return jsonify({"error": "Invalid input. 'instances' key is required."}), 400
21
22        # Example model logic: simple identity transformation or mock prediction
23        instances = data.get('instances', [])
24        predictions = [instance for instance in instances]
25
26        # Standard expects JSON output with a 'predictions' key
27        return jsonify({"predictions": predictions}), 200
28    except Exception as e:
29        return jsonify({"error": str(e)}), 500
30
31if __name__ == '__main__':
32    # Standard containers typically listen on port 8080 by default
33    port = int(os.environ.get('PORT', 8080))
34    app.run(host='0.0.0.0', port=port)