cringbuffer/test_ringbuffer.py at master · ctrl-labs/cringbuffer · GitHub

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#!/usr/bin/env python3

import ctypes

import gc

import logging

import multiprocessing

import queue

import threading

import time

import unittest

import ringbuffer

class TestException(Exception):

pass

class ReadersWriterLockTest(unittest.TestCase):

def setUp(self):

self.lock = ringbuffer.ReadersWriterLock()

self.assert_unlocked()

self.result_queues = {}

def assert_unlocked(self):

self.assertEqual(0, self.lock.readers.value)

self.assertFalse(self.lock.writer.value)

def assert_readers(self, count):

self.assertEqual(count, self.lock.readers.value)

self.assertFalse(self.lock.writer.value)

def assert_writer(self):

self.assertEqual(0, self.lock.readers.value)

self.assertTrue(self.lock.writer.value)

def reader_count(self):

return self.lock.readers.value

def async(self, func):

def wrapper(result_queue):

result = func()

result_queue.put(result)

result_queue = multiprocessing.Queue()

process = multiprocessing.Process(

target=wrapper, args=(result_queue, ))

self.result_queues[process] = result_queue

process.start()

return process

def get_result(self, process):

process.join()

return self.result_queues[process].get()

def test_read_then_write(self):

with self.lock.for_read():

self.assert_readers(1)

self.assert_unlocked()

with self.lock.for_write():

self.assert_writer()

self.assert_unlocked()

def test_reentrant_readers(self):

with self.lock.for_read():

self.assert_readers(1)

with self.lock.for_read():

self.assert_readers(2)

with self.lock.for_read():

self.assert_readers(3)

self.assert_readers(2)

self.assert_readers(1)

self.assert_unlocked()

def test_writer_blocks_reader(self):

with self.lock.for_write():

event = multiprocessing.Event()

def test():

self.assert_writer()

# Caller will block until this event is released.

event.set()

with self.lock.for_read():

self.assert_readers(1)

return 'read'

r = self.async(test)

# Wait until we can confirm that the reader is locked out.

event.wait()

self.assert_writer()

self.assertEqual('read', self.get_result(r))

self.assert_unlocked()

def test_writer_blocks_multiple_readers(self):

with self.lock.for_write():

before_read = multiprocessing.Barrier(3)

during_read = multiprocessing.Barrier(2)

after_read = multiprocessing.Barrier(2)

def test():

self.assert_writer()

before_read.wait()

with self.lock.for_read():

during_read.wait()

value = self.reader_count()

after_read.wait()

return value

r1 = self.async(test)

r2 = self.async(test)

# Wait until we can confirm that all readers are locked out

before_read.wait()

self.assert_writer()

self.assertEqual(2, self.get_result(r1))

self.assertEqual(2, self.get_result(r2))

self.assert_unlocked()

def test_reader_blocks_writer(self):

with self.lock.for_read():

before_write = multiprocessing.Barrier(2)

def test():

self.assert_readers(1)

before_write.wait()

with self.lock.for_write():

self.assert_writer()

return 'written'

writer = self.async(test)

# Wait until we can confirm that all writers are locked out.

before_write.wait()

self.assert_readers(1)

self.assertEqual('written', self.get_result(writer))

self.assert_unlocked()

def test_multiple_readers_block_writer(self):

with self.lock.for_read():

before_read = multiprocessing.Barrier(3)

after_read = multiprocessing.Barrier(2)

def test_reader():

self.assert_readers(1)

with self.lock.for_read():

before_read.wait()

value = self.reader_count()

after_read.wait()

return value

def test_writer():

before_read.wait()

with self.lock.for_write():

self.assert_writer()

return 'written'

reader = self.async(test_reader)

writer = self.async(test_writer)

# Wait for the write to be blocked by multiple readers.

before_read.wait()

self.assert_readers(2)

after_read.wait()

self.assertEqual(2, self.get_result(reader))

self.assertEqual('written', self.get_result(writer))

self.assert_unlocked()

def test_multiple_writers_block_each_other(self):

with self.lock.for_write():

before_write = multiprocessing.Barrier(2)

def test():

before_write.wait()

with self.lock.for_write():

self.assert_writer()

return 'written'

writer = self.async(test)

before_write.wait()

self.assert_writer()

self.assertEqual('written', self.get_result(writer))

self.assert_unlocked()

def test_wait_for_write(self):

event = multiprocessing.Event()

wait_count = 0

with self.lock.for_read():

def test():

with self.lock.for_write():

self.assert_writer()

event.set()

return 'written'

writer = self.async(test)

while not event.is_set():

self.assert_readers(1)

wait_count += 1

self.lock.wait_for_write()

self.assert_readers(1)

self.assertEqual('written', self.get_result(writer))

self.assert_unlocked()

self.assertLessEqual(wait_count, 2)

def test_wait_for_write__writer_already_waiting_for_reader(self):

event = multiprocessing.Event()

with self.lock.for_read():

def test():

event.set()

with self.lock.for_write():

self.assert_writer()

event.set()

return 'written'

writer = self.async(test)

event.wait()

# Force a context switch so the writer is waiting

time.sleep(0.1)

self.lock.wait_for_write()

self.assert_readers(1)

self.assertEqual('written', self.get_result(writer))

self.assert_unlocked()

def test_wait_for_write_without_lock(self):

self.assert_unlocked()

self.assertRaises(ringbuffer.InternalLockingError,

self.lock.wait_for_write)

def test_unlock_readers_on_exception(self):

try:

with self.lock.for_read():

self.assert_readers(1)

raise TestException

except TestException:

self.assert_unlocked()

else:

self.fail()

def test_unlock_writer_on_exception(self):

try:

with self.lock.for_write():

self.assert_writer()

raise TestException

except TestException:

self.assert_unlocked()

else:

self.fail()

class Expecter:

def __init__(self, ring, pointer, testcase):

self.ring = ring

self.pointer = pointer

self.testcase = testcase

def expect_index(self, i):

self.testcase.assertEqual(i, self.pointer.get().index)

def write(self, data):

self.ring.try_write(data)

def write_multiple(self, data):

self.ring.try_write_multiple(data)

def _get_read_func(self, blocking):

if blocking:

return self.ring.blocking_read

else:

return self.ring.try_read

def expect_read(self, expected_data, blocking=False):

read = self._get_read_func(blocking)

data = read(self.pointer)

item = data[0]

for k, v in expected_data.items():

value = getattr(item, k)

self.testcase.assertEqual(v, value, 'Data field {} was: {}'.format(

k, value))

def expect_multi_read(self, expected_data_list, length=1, blocking=False):

read = self._get_read_func(blocking)

data = read(self.pointer, length=length)

self.testcase.assertEqual(

len(expected_data_list), len(data), 'Data length is not correct')

for i, expected_data in enumerate(expected_data_list):

for k, v in expected_data.items():

value = getattr(data[i], k)

self.testcase.assertEqual(v, value,

'Data field {} was: {}'.format(

k, value))

def expect_read_all(self, expected_data_list):

data = self.ring.try_read_all(self.pointer)

self.testcase.assertEqual(

len(expected_data_list), len(data), 'Data length is not correct')

for i, expected_data in enumerate(expected_data_list):

for k, v in expected_data.items():

value = getattr(data[i], k)

self.testcase.assertEqual(v, value,

'Data field {}: was {}'.format(

k, value))

def expect_waiting_for_writer(self):

# There's no blocking version of this because the WaitingForWriterError

# is what's used to determine when to block on the condition variable.

self.testcase.assertRaises(ringbuffer.WaitingForWriterError,

self.ring.try_read, self.pointer)

def expect_waiting_for_reader(self):

self.testcase.assertRaises(ringbuffer.WaitingForReaderError,

self.ring.try_write, TStruct())

def writer_done(self):

self.ring.writer_done()

def expect_writer_finished(self, blocking=False):

read = self._get_read_func(blocking)

self.testcase.assertRaises(ringbuffer.WriterFinishedError, read,

self.pointer)

def expect_already_closed(self):

self.testcase.assertRaises(ringbuffer.AlreadyClosedError,

self.ring.try_write, TStruct())

def force_reader_sync(self):

self.ring.force_reader_sync()

def expect_try_read_type(self, type_or_class):

data = self.ring.try_read(self.pointer)

self.testcase.assertTrue(isinstance(data, type_or_class))

class AsyncProxy:

def __init__(self, expecter, in_queue, error_queue):

self.expecter = expecter

self.in_queue = in_queue

self.error_queue = error_queue

self.runner = None

def run(self):

while True:

item = self.in_queue.get()

try:

if item == 'done':

logging.debug('Exiting %r', self.runner)

return

name, args, kwargs = item

logging.debug('Running %s(%r, %r)', name, args, kwargs)

try:

getattr(self.expecter, name)(*args, **kwargs)

except Exception as e:

logging.exception('Problem running %s(*%r, **%r)', name,

args, kwargs)

self.error_queue.put(e)

finally:

self.in_queue.task_done()

def shutdown(self):

self.in_queue.put('done')

def __getattr__(self, name):

def proxy(*args, **kwargs):

self.expecter.testcase.assertTrue(

self.runner,

'Must call start_proxies() before setting test expectations')

# This queue is used to sequence operations between functions

# that are running asynchronously (threads or processes).

self.in_queue.put((name, args, kwargs))

# If this test function is running in blocking mode, that means

# the locking and sequencing is built into the semantics of the

# function call itself. That means we can skip waiting for the

# asynchronous function to consume the queue before letting

# subsequent test methods run.

if kwargs.get('blocking'):

# Allow a context switch so the asynchronous function has

# a chance to actually start the function call.

time.sleep(0.1)

else:

self.in_queue.join()

return proxy

class TStruct(ctypes.Structure):

_fields_ = (('i', ctypes.c_int32), ('f', ctypes.c_float))

class RingBufferTestBase:

def setUp(self):

self.ring = ringbuffer.RingBuffer(c_type=TStruct, slot_count=10)

self.proxies = []

self.error_queue = self.new_queue()

def tearDown(self):

for proxy in self.proxies:

if proxy.runner:

proxy.shutdown()

for proxy in self.proxies:

if proxy.runner:

proxy.in_queue.join()

if not self.error_queue.empty():

raise self.error_queue.get()

# Force child processes and pipes to be garbage collected, otherwise

# we'll run out of file descriptors.

gc.collect()

def new_queue(self):

raise NotImplementedError

def run_proxy(self, proxy):

raise NotImplementedError

def start_proxies(self):

for proxy in self.proxies:

self.run_proxy(proxy)

def new_reader(self):

expecter = Expecter(self.ring, self.ring.new_reader(), self)

proxy = AsyncProxy(expecter, self.new_queue(), self.error_queue)

self.proxies.append(proxy)

return proxy

def new_writer(self):

self.ring.new_writer()

expecter = Expecter(self.ring, self.ring.writer, self)

proxy = AsyncProxy(expecter, self.new_queue(), self.error_queue)

self.proxies.append(proxy)

return proxy

def test_write_simple(self):

writer = self.new_writer()

self.start_proxies()

o = TStruct(i=22, f=2.2)

writer.write(o)

def test_write_string(self):

writer = self.new_writer()

self.start_proxies()

self.assertTrue(self.error_queue.empty())

writer.write('this does not work')

error = self.error_queue.get()

self.assertTrue(isinstance(error, TypeError))

def _do_read_single_write(self, blocking):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

writer.expect_index(0)

o = TStruct(i=22, f=2.2)

writer.write(o)

writer.expect_index(1)

reader.expect_index(0)

reader.expect_read({'i': 22}, blocking=blocking)

reader.expect_index(1)

def test_read_single_write_blocking(self):

self._do_read_single_write(True)

def test_read_single_write_non_blocking(self):

self._do_read_single_write(False)

def _do_read_ahead_of_writes(self, blocking):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

reader.expect_waiting_for_writer()

o = TStruct(i=22, f=2.2)

writer.write(o)

reader.expect_read({'i': 22}, blocking=blocking)

def test_read_ahead_of_writes_blocking(self):

self._do_read_ahead_of_writes(True)

def test_read_ahead_of_writes_non_blocking(self):

self._do_read_ahead_of_writes(False)

def _do_two_reads_one_behind_one_ahead(self, blocking):

r1 = self.new_reader()

r2 = self.new_reader()

writer = self.new_writer()

self.start_proxies()

o = TStruct(i=22, f=2.2)

writer.write(o)

r1.expect_read({'i': 22}, blocking=blocking)

r1.expect_waiting_for_writer()

r2.expect_read({'i': 22}, blocking=blocking)

r2.expect_waiting_for_writer()

def test_two_reads_one_behind_one_ahead_blocking(self):

self._do_two_reads_one_behind_one_ahead(True)

def test_two_reads_one_behind_one_ahead_non_blocking(self):

self._do_two_reads_one_behind_one_ahead(False)

def test_write_conflict_first_slot(self):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

for i in range(self.ring.slot_count):

o = TStruct(i=i, f=2.2)

writer.write(o)

# The writer has wrapped around and is now waiting for the reader

# to free up a slot. They have the same index, but are different

# generations.

reader.expect_index(0)

writer.expect_index(0)

writer.expect_waiting_for_reader()

reader.expect_read({'i': 0})

o = TStruct(i=1111, f=2.2)

writer.write(o)

for i in range(1, self.ring.slot_count):

reader.expect_read({'i': i})

reader.expect_index(0)

reader.expect_read({'i': 1111})

def test_write_conflict_last_slot(self):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

last_slot = self.ring.slot_count - 1

self.assertGreater(last_slot, 0)

for i in range(last_slot):

writer.write(TStruct(i=i))

reader.expect_read({'i': i})

writer.expect_index(last_slot)

reader.expect_index(last_slot)

# The reader's pointed at the last slot, now wrap around the writer

# to catch up. They'll have the same index, but different generation

# numbers.

for i in range(self.ring.slot_count):

writer.write(TStruct(i=self.ring.slot_count + i))

reader.expect_index(last_slot)

writer.expect_index(last_slot)

writer.expect_waiting_for_reader()

reader.expect_read({'i': self.ring.slot_count})

writer.write(TStruct())

writer.expect_index(0)

reader.expect_index(0)

def test_create_reader_after_writing(self):

writer = self.new_writer()

self.start_proxies()

self.new_reader() # No error because no writes happened yet.

writer.write(TStruct())

self.assertRaises(ringbuffer.MustCreatedReadersBeforeWritingError,

self.new_reader)

def _do_read_after_close_beginning(self, blocking):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

writer.writer_done()

reader.expect_writer_finished(blocking=blocking)

def test_read_after_close_beginning_blocking(self):

self._do_read_after_close_beginning(True)

def test_read_after_close_beginning_non_blocking(self):

self._do_read_after_close_beginning(False)

def _do_close_before_read(self, blocking):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

writer.write(TStruct(i=4545))

writer.writer_done()

writer.expect_index(1)

reader.expect_read({'i': 4545})

reader.expect_writer_finished(blocking=blocking)

reader.expect_index(1)

def test_close_before_read_blocking(self):

self._do_close_before_read(True)

def test_close_before_read_non_blocking(self):

self._do_close_before_read(False)

def _do_close_after_read(self, blocking):

reader = self.new_reader()

writer = self.new_writer()

self.start_proxies()

writer.write(TStruct(i=3434))

reader.expect_read({'i': 3434})

reader.expect_waiting_for_writer()

reader.expect_index(1)

writer.writer_done()

writer.expect_index(1)

reader.expect_writer_finished(blocking=blocking)

def test_close_after_read_blocking(self):

self._do_close_after_read(True)

def test_close_after_read_non_blocking(self):

self._do_close_after_read(False)

def test_close_then_write(self):

writer = self.new_writer()

self.start_proxies()

writer.write(TStruct())

writer.writer_done()

writer.expect_already_closed()

def test_blocking_readers_wake_up_after_write(self):

writer = self.new_writer()

r1 = self.new_reader()

r2 = self.new_reader()

self.start_proxies()

r1.expect_read({'i': 11}, blocking=True)

r2.expect_read({'i': 11}, blocking=True)

writer.write(TStruct(i=11))

def test_blocking_readers_wake_up_after_close(self):

writer = self.new_writer()

r1 = self.new_reader()

r2 = self.new_reader()

self.start_proxies()

r1.expect_writer_finished(blocking=True)

r2.expect_writer_finished(blocking=True)

writer.writer_done()

def test_force_reader_sync(self):

writer = self.new_writer()

r1 = self.new_reader()

r2 = self.new_reader()

self.start_proxies()

writer.write(TStruct(i=1))

writer.write(TStruct(i=2))

writer.write(TStruct(i=3))

writer.expect_index(3)

r1.expect_index(0)

r2.expect_index(0)

writer.force_reader_sync()

r1.expect_index(3)

r2.expect_index(3)

def _do_multiple_writers(self, blocking):

w1 = self.new_writer()

w2 = self.new_writer()

reader = self.new_reader()

self.start_proxies()

w1.write(TStruct(i=11))

w1.expect_index(1)

w2.expect_index(1)

w2.write(TStruct(i=22))

w1.expect_index(2)

w2.expect_index(2)

w2.write(TStruct(i=33))

w1.expect_index(3)

w2.expect_index(3)

w1.write(TStruct(i=44))

w1.expect_index(4)

w2.expect_index(4)

reader.expect_read({'i': 11}, blocking=blocking)

reader.expect_read({'i': 22}, blocking=blocking)

reader.expect_read({'i': 33}, blocking=blocking)

reader.expect_read({'i': 44}, blocking=blocking)

def test_multiple_writers_blocking(self):

self._do_multiple_writers(True)

def test_multiple_writers_non_blocking(self):

self._do_multiple_writers(False)

def _do_test_multiple_writers_close(self, blocking):

w1 = self.new_writer()

w2 = self.new_writer()

reader = self.new_reader()

self.start_proxies()

w1.write(TStruct(i=11))

w1.writer_done()

w2.write(TStruct(i=22))

w2.writer_done()

reader.expect_read({'i': 11}, blocking=blocking)

reader.expect_read({'i': 22}, blocking=blocking)

reader.expect_writer_finished(blocking=blocking)

def test_multiple_writers_close_blocking(self):

self._do_test_multiple_writers_close(True)

def test_multiple_writers_close_non_blocking(self):

self._do_test_multiple_writers_close(False)

def _do_start_read_before_writer_setup(self, blocking):

reader = self.new_reader()

self.start_proxies()

reader.expect_writer_finished(blocking=blocking)

def test_start_read_before_writer_setup_blocking(self):

self._do_start_read_before_writer_setup(True)

def test_start_read_before_writer_setup_non_blocking(self):

self._do_start_read_before_writer_setup(False)

def test_read_older_gen(self):

w = self.new_writer()

reader = self.new_reader()

self.start_proxies()

for i in range(0, 10):

w.write(TStruct(i=i))

reader.expect_multi_read(

[{

'i': 0

}, {

'i': 1

}, {

'i': 2

}, {

'i': 3

}, {

'i': 4

}], length=5)

for i in range(10, 15):

w.write(TStruct(i=i))

reader.expect_multi_read(

[{

'i': 5

}, {

'i': 6

}, {

'i': 7

}, {

'i': 8

}, {

'i': 9

}, {

'i': 10

}, {

'i': 11

}],

length=7)

w.writer_done()

def test_read_all(self):

w = self.new_writer()

reader = self.new_reader()

self.start_proxies()

for i in range(0, 10):

w.write(TStruct(i=i))

expected_data = [{'i': index} for index in range(0, 10)]

reader.expect_read_all(expected_data)

for i in range(10, 15):

w.write(TStruct(i=i))

expected_data = [{'i': index} for index in range(10, 15)]

reader.expect_read_all(expected_data)

w.writer_done()

class ThreadingTest(RingBufferTestBase, unittest.TestCase):

def new_queue(self):

return queue.Queue()

def run_proxy(self, proxy):

thread = threading.Thread(target=proxy.run)

proxy.runner = thread

thread.daemon = True

thread.start()

class MultiprocessingTest(RingBufferTestBase, unittest.TestCase):

def new_queue(self):

return multiprocessing.JoinableQueue()

def run_proxy(self, proxy):

process = multiprocessing.Process(target=proxy.run)

proxy.runner = process

process.daemon = True

process.start()

if __name__ == '__main__':

logging.getLogger().setLevel(logging.DEBUG)

unittest.main()

cringbuffer/test_ringbuffer.py at master · ctrl-labs/cringbuffer · GitHub

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