Python CORS HTTP localhost web dev server script (includes logging to file)

serve.py

#!/user/bin/env python3
# encoding: utf-8
"""Use instead of `python3 -http.server 8000` when you need CORS"""

from sys import stdout
from datetime import datetime
from http.server import HTTPServer, SimpleHTTPRequestHandler
from atexit import register as atexit

# For logging (to both console and file)
global log
log = open('serve' + datetime.now().strftime('%Y%m%d') + '.log', 'w')
def onexit():
    log.close()
atexit(onexit)

# For HTTPServer
class CORSRequestHandler(SimpleHTTPRequestHandler):
    def end_headers(self):
        self.send_response(200, "ok")
        self.send_header('Access-Control-Allow-Credentials', 'true')
        self.send_header('Access-Control-Allow-Origin', '*')
        self.send_header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS')
        self.send_header('Access-Control-Allow-Headers', 'X-Requested-With, Content-Type')
        self.send_header('Cache-Control', 'no-store, no-cache, must-revalidate')
        return super(CORSRequestHandler, self).end_headers()
    
    def do_OPTIONS(self):
        self.send_response(200, "ok")
        self.send_header('Access-Control-Allow-Credentials', 'true')
        self.send_header('Access-Control-Allow-Origin', '*')
        self.send_header('Access-Control-Allow-Headers', 'X-Requested-With, Content-Type')
        self.send_header('Cache-Control', 'no-store, no-cache, must-revalidate')
        return super(CORSRequestHandler, self).end_headers()
    
    def log_request(self, code='-', size='-'):
        self.log_message('"%s" %s %s',
                         self.requestline, str(code), str(size))
    
    def log_error(self, format, *args):
        self.log_message(format, *args)
    
    def log_message(self, format, *args):
        msg = ("%s - - [%s] %s\n" %
                         (self.address_string(),
                          self.log_date_time_string(),
                          format%args))
        stdout.write(msg)
        log.write(msg)
        log.flush()

# Host address to listen on (HOST:PORT)
HOST = "localhost"
# Port to listen on (HOST:PORT)
PORT = 8000

print("HTTPServer started on " + str(HOST) + " at port " + str(PORT))
print("To change the port, modify the PORT variable in this script then close and restart this script.")

# Start server
httpd = HTTPServer((HOST, PORT), CORSRequestHandler)
httpd.serve_forever()