app.py

"""
 * Copyright 2020 Mia srl
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
"""

import tornado.ioloop
import tornado.web
import requests
from functools import lru_cache
import logging
import os
import psutil
import json


@lru_cache(maxsize=None)
def calc_fib(n):
    if n <= 0:
        return 0
    elif n == 1:
        return 1
    else:
        return calc_fib(n - 1) + calc_fib(n - 2)


class HelloHandler(tornado.web.RequestHandler):
    def get(self):
        hello = {'message': "Hello World"}
        self.finish(json.dumps(hello))


class Fibonacci(tornado.web.RequestHandler):
    def get(self, num):
        logging.info('Memory before: ' +
                     str(process.memory_info().rss/1000000))
        start_num = int(num.strip())
        logging.info('Calculating fibonacci for n=%d', start_num)
        res = str(calc_fib(start_num))
        logging.info('Result is %s', res)
        logging.info('Memory after: ' + str(process.memory_info().rss/1000000))
        self.finish(res)


class Cars(tornado.web.RequestHandler):
    def get(self):
        logging.info('Request stress')
        r = requests.get('http://crud-service/cars/', '')
        logging.info('Result is %s', r.text)
        self.finish(json.dumps(r.json()))


class ReadyResource(tornado.web.RequestHandler):
    def get(self):
        ready = {'statusOK': True}
        self.finish(json.dumps(ready))


class HealthResource(tornado.web.RequestHandler):
    def get(self,):
        health = {'statusOK': True}
        self.finish(json.dumps(health))


def make_app():
    return tornado.web.Application([
        (r"/hello", HelloHandler),
        (r"/-/ready", ReadyResource),
        (r"/-/healthz", HealthResource),
        (r"/fib/([^/]+)?", Fibonacci),
        (r"/crud/cars", Cars),
    ])


if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO)
    process = psutil.Process(os.getpid())
    app = make_app()
    server = tornado.httpserver.HTTPServer(app)
    server.bind(3000)
    server.start(0)
    logging.info('Python Tornado Server is up and running!!!')
    tornado.ioloop.IOLoop.current().start()