baseimage-tutorial-framework/lib/tfw/util.py

import xmlrpc.client
from contextlib import suppress
from xmlrpc.client import Fault as SupervisorFault
from time import time, sleep
from functools import wraps

from tfw.config import tfwenv


def create_source_code_response_data(filename, content, language):
    return {
        'filename': filename,
        'content': content,
        'language': language
    }


class SupervisorMixin:
    supervisor = xmlrpc.client.ServerProxy(tfwenv.SUPERVISOR_HTTP_URI).supervisor

    def stop_process(self):
        with suppress(SupervisorFault):
            self.supervisor.stopProcess(self.process_name)

    def start_process(self):
        self.supervisor.startProcess(self.process_name)

    def restart_process(self):
        self.stop_process()
        self.start_process()


class RateLimiter:
    def __init__(self, rate_per_second):
        self.min_interval = 1 / float(rate_per_second)
        self.last_call = time()

    def __call__(self, fun):
        @wraps(fun)
        def wrapper(*args, **kwargs):
            self._limit_rate()
            fun(*args, **kwargs)
        return wrapper

    def _limit_rate(self):
        since_last_call = time() - self.last_call
        to_next_call = self.min_interval - since_last_call
        self.last_call = time()
        if to_next_call > 0:
            sleep(to_next_call)