class RWLockTestCase(unittest.TestCase):
def setUp(self):
self.lock = RWLock()
def test_readers(self):
with self.lock.read_lock():
self.assertEqual(self.lock.readers, 1)
self.assertEqual(self.lock.writers, 0)
self.assertFalse(self.lock.blocked_for_readers)
self.assertTrue(self.lock.blocked_for_writers)
# Multiple readers can hold the lock simultaneously
with self.lock.read_lock():
self.assertEqual(self.lock.readers, 2)
self.assertEqual(self.lock.writers, 0)
self.assertFalse(self.lock.blocked_for_readers)
self.assertTrue(self.lock.blocked_for_writers)
def test_writers(self):
with self.lock.write_lock():
self.assertEqual(self.lock.readers, 0)
self.assertEqual(self.lock.writers, 1)
self.assertTrue(self.lock.blocked_for_readers)
self.assertTrue(self.lock.blocked_for_writers)
def test_unlocked(self):
self.assertEqual(self.lock.readers, 0)
self.assertEqual(self.lock.writers, 0)
self.assertFalse(self.lock.blocked_for_readers)
self.assertFalse(self.lock.blocked_for_writers)
def __init__(self, config: configparser.ConfigParser):
"""
Initialise the handler. The config is provided from the configuration file, which is guaranteed to have a
[handler] section.
Objects of this class *MUST* be thread-safe.
:param config: Contents of the configuration file
"""
self.config = config
# Provide a lock so that our state can be protected during a reload
self.lock = RWLock()
# Implement initialisation as a reload
self.handle_reload()
class MessageHandler(ABC):
"""
This is the base class for all message handlers. Subclassing this provides the most flexibility but it does require
the most effort to implement correctly as well.
"""
def __init__(self, config: configparser.ConfigParser):
"""
Initialise the handler. The config is provided from the configuration file, which is guaranteed to have a
[handler] section.
Objects of this class *MUST* be thread-safe.
:param config: Contents of the configuration file
"""
self.config = config
# Provide a lock so that our state can be protected during a reload
self.lock = RWLock()
# Implement initialisation as a reload
self.handle_reload()
def reload(self, new_config: configparser.ConfigParser):
"""
This is called by the server on SIGHUP so the configuration can be reloaded, caches can be cleared etc.
Subclasses shouldn't overwrite this method but the handle_reload() method, which will automatically be
protected with a lock.
:param new_config: The new configuration after the reload
"""
with self.lock.write_lock():
self.config = new_config
self.handle_reload()
# noinspection PyMethodMayBeStatic
def handle_reload(self):
"""
This method can be overwritten by subclasses to handle configuration reloads.
"""
pass
@abstractmethod
def handle(self, received_message: RelayServerMessage, received_over_multicast: bool) -> Message or None:
"""
def setUp(self):
self.lock = RWLock()
