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import asyncio
import contextlib
import pytest
from redis.asyncio import Redis
from redis.asyncio.cluster import RedisCluster
from redis.asyncio.connection import async_timeout
class DelayProxy:
def __init__(self, addr, redis_addr, delay: float = 0.0):
self.addr = addr
self.redis_addr = redis_addr
self.delay = delay
self.send_event = asyncio.Event()
self.server = None
self.task = None
async def __aenter__(self):
await self.start()
return self
async def __aexit__(self, *args):
await self.stop()
async def start(self):
# test that we can connect to redis
async with async_timeout(2):
_, redis_writer = await asyncio.open_connection(*self.redis_addr)
redis_writer.close()
self.server = await asyncio.start_server(
self.handle, *self.addr, reuse_address=True
)
self.task = asyncio.create_task(self.server.serve_forever())
@contextlib.contextmanager
def set_delay(self, delay: float = 0.0):
"""
Allow to override the delay for parts of tests which aren't time dependent,
to speed up execution.
"""
old_delay = self.delay
self.delay = delay
try:
yield
finally:
self.delay = old_delay
async def handle(self, reader, writer):
# establish connection to redis
redis_reader, redis_writer = await asyncio.open_connection(*self.redis_addr)
try:
pipe1 = asyncio.create_task(
self.pipe(reader, redis_writer, "to redis:", self.send_event)
)
pipe2 = asyncio.create_task(self.pipe(redis_reader, writer, "from redis:"))
await asyncio.gather(pipe1, pipe2)
finally:
redis_writer.close()
async def stop(self):
# clean up enough so that we can reuse the looper
self.task.cancel()
try:
await self.task
except asyncio.CancelledError:
pass
loop = self.server.get_loop()
await loop.shutdown_asyncgens()
async def pipe(
self,
reader: asyncio.StreamReader,
writer: asyncio.StreamWriter,
name="",
event: asyncio.Event = None,
):
while True:
data = await reader.read(1000)
if not data:
break
# print(f"{name} read {len(data)} delay {self.delay}")
if event:
event.set()
await asyncio.sleep(self.delay)
writer.write(data)
await writer.drain()
@pytest.mark.onlynoncluster
@pytest.mark.parametrize("delay", argvalues=[0.05, 0.5, 1, 2])
async def test_standalone(delay, master_host):
# create a tcp socket proxy that relays data to Redis and back,
# inserting 0.1 seconds of delay
async with DelayProxy(addr=("127.0.0.1", 5380), redis_addr=master_host) as dp:
for b in [True, False]:
# note that we connect to proxy, rather than to Redis directly
async with Redis(
host="127.0.0.1", port=5380, single_connection_client=b
) as r:
await r.set("foo", "foo")
await r.set("bar", "bar")
async def op(r):
with dp.set_delay(delay * 2):
return await r.get(
"foo"
) # <-- this is the operation we want to cancel
dp.send_event.clear()
t = asyncio.create_task(op(r))
# Wait until the task has sent, and then some, to make sure it has
# settled on the read.
await dp.send_event.wait()
await asyncio.sleep(0.01) # a little extra time for prudence
t.cancel()
with pytest.raises(asyncio.CancelledError):
await t
# make sure that our previous request, cancelled while waiting for
# a repsponse, didn't leave the connection open andin a bad state
assert await r.get("bar") == b"bar"
assert await r.ping()
assert await r.get("foo") == b"foo"
@pytest.mark.onlynoncluster
@pytest.mark.parametrize("delay", argvalues=[0.05, 0.5, 1, 2])
async def test_standalone_pipeline(delay, master_host):
async with DelayProxy(addr=("127.0.0.1", 5380), redis_addr=master_host) as dp:
for b in [True, False]:
async with Redis(
host="127.0.0.1", port=5380, single_connection_client=b
) as r:
await r.set("foo", "foo")
await r.set("bar", "bar")
pipe = r.pipeline()
pipe2 = r.pipeline()
pipe2.get("bar")
pipe2.ping()
pipe2.get("foo")
async def op(pipe):
with dp.set_delay(delay * 2):
return await pipe.get(
"foo"
).execute() # <-- this is the operation we want to cancel
dp.send_event.clear()
t = asyncio.create_task(op(pipe))
# wait until task has settled on the read
await dp.send_event.wait()
await asyncio.sleep(0.01)
t.cancel()
with pytest.raises(asyncio.CancelledError):
await t
# we have now cancelled the pieline in the middle of a request,
# make sure that the connection is still usable
pipe.get("bar")
pipe.ping()
pipe.get("foo")
await pipe.reset()
# check that the pipeline is empty after reset
assert await pipe.execute() == []
# validating that the pipeline can be used as it could previously
pipe.get("bar")
pipe.ping()
pipe.get("foo")
assert await pipe.execute() == [b"bar", True, b"foo"]
assert await pipe2.execute() == [b"bar", True, b"foo"]
@pytest.mark.onlycluster
async def test_cluster(master_host):
delay = 0.1
cluster_port = 6372
remap_base = 7372
n_nodes = 6
hostname, _ = master_host
def remap(address):
host, port = address
return host, remap_base + port - cluster_port
proxies = []
for i in range(n_nodes):
port = cluster_port + i
remapped = remap_base + i
forward_addr = hostname, port
proxy = DelayProxy(addr=("127.0.0.1", remapped), redis_addr=forward_addr)
proxies.append(proxy)
def all_clear():
for p in proxies:
p.send_event.clear()
async def wait_for_send():
asyncio.wait(
[p.send_event.wait() for p in proxies], return_when=asyncio.FIRST_COMPLETED
)
@contextlib.contextmanager
def set_delay(delay: float):
with contextlib.ExitStack() as stack:
for p in proxies:
stack.enter_context(p.set_delay(delay))
yield
async with contextlib.AsyncExitStack() as stack:
for p in proxies:
await stack.enter_async_context(p)
with contextlib.closing(
RedisCluster.from_url(
f"redis://127.0.0.1:{remap_base}", address_remap=remap
)
) as r:
await r.initialize()
await r.set("foo", "foo")
await r.set("bar", "bar")
async def op(r):
with set_delay(delay):
return await r.get("foo")
all_clear()
t = asyncio.create_task(op(r))
# Wait for whichever DelayProxy gets the request first
await wait_for_send()
await asyncio.sleep(0.01)
t.cancel()
with pytest.raises(asyncio.CancelledError):
await t
# try a number of requests to excercise all the connections
async def doit():
assert await r.get("bar") == b"bar"
assert await r.ping()
assert await r.get("foo") == b"foo"
await asyncio.gather(*[doit() for _ in range(10)])
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