sessionpool.py

from collections import namedtuple
from threading import Lock
import time


class Session(object):
    """ 
    This should actually be a Session object from the requests library. I'm
    just lazy and made a simple stand-in.
    """
    pass


# I put very little thought into the actual list of settings here. Really it
# should just be a full list of whatever ssl settings we support.
SSLSettings = namedtuple('SSLSettings', ['ca_cert', 'client_cert', 'client_key', 'verify_remote_ca'])
SessionEntry = namedtuple('SessionEntry', ['last_used', 'session'])


class SessionPool(object):
    def __init__(self):
        self._sessions = {}
        self._lock = Lock()

    def get_session(self, ssl_settings):
        """ 
        :type ssl_settings: SSLSettings
        :rtype: Session
        """
        with self._lock:
            if ssl_settings in self._sessions:
                entry = self._sessions[ssl_settings]
                entry.last_used = time.time()
            else:
                entry = SessionEntry(time.time(), Session())
                self._sessions[ssl_settings] = entry
            return entry.session

    def evict_old(self):
        """ 
        Something would need to call this periodically.
        """
        with self._lock:
            oldest_allowed = time.time() - 300 
            for key, entry in self._sessions.items():
                if entry.last_used < oldest_allowed:
                    del self._sessions[key]