Math Engine

math_engine.py

#!/usr/bin/env python

"""
A Flask-powered math engine microservice.
"""

from flask import Flask, request, jsonify, Response
import json
import datetime


app = Flask(__name__)

# Very basic history storage. In a proper app, this would be
# something a bit more robust, eh?
history = []

@app.route("/")
def hello():
    return "Hellooooo Math!"

@app.route("/math_engine")
def math_engine():
    """Calculate sum/product for a given set of values."""
    raw_values = request.args['values']
    parsed_values = [float(v) for v in json.loads(raw_values)]
    values_sum = 0
    values_product = 1
    for v in parsed_values:
        values_sum += v
        values_product *= v
    result = {'sum': values_sum, 'product': values_product}
    _add_to_history(request, parsed_values, result)
    return jsonify(result)

def _add_to_history(request, parsed_values, result):
    """Save a request/result to the history."""
    history_item = {
        "ip": request.remote_addr, 
        "timestamp": datetime.datetime.now().isoformat(),
        "values": parsed_values,
    }
    history_item.update(result)
    history.append(history_item)

@app.route("/history")
def get_history():
    """Get history items. If 'num_items' argument 
    is not specified, returns max(10,len(history)) items."""
    num_items = int(request.args.get('num_items', 10))
    result = list(reversed(history[-1*num_items:]))
    return Response(json.dumps(result),  mimetype='application/json')


if __name__ == "__main__":
    app.run(debug=True)