forked-synapse/tests/util/test_stream_change_cache.py
Richard van der Hoff 13683a3a22
Extend StreamChangeCache to support multiple entities per stream ID (#7303)
First some background: StreamChangeCache is used to keep track of what "entities" have 
changed since a given stream ID. So for example, we might use it to keep track of when the last
to-device message for a given user was received [1], and hence whether we need to pull any to-device messages from the database on a sync [2].

Now, it turns out that StreamChangeCache didn't support more than one thing being changed at
a given stream_id (this was part of the problem with #7206). However, it's entirely valid to send
to-device messages to more than one user at a time.

As it turns out, this did in fact work, because *some* methods of StreamChangeCache coped
ok with having multiple things changing on the same stream ID, and it seems we never actually
use the methods which don't work on the stream change caches where we allow multiple
changes at the same stream ID. But that feels horribly fragile, hence: let's update
StreamChangeCache to properly support this, and add some typing and some more tests while
we're at it.

[1]: https://github.com/matrix-org/synapse/blob/release-v1.12.3/synapse/storage/data_stores/main/deviceinbox.py#L301
[2]: https://github.com/matrix-org/synapse/blob/release-v1.12.3/synapse/storage/data_stores/main/deviceinbox.py#L47-L51
2020-04-22 13:45:40 +01:00

250 lines
9.5 KiB
Python

from mock import patch
from synapse.util.caches.stream_change_cache import StreamChangeCache
from tests import unittest
class StreamChangeCacheTests(unittest.TestCase):
"""
Tests for StreamChangeCache.
"""
def test_prefilled_cache(self):
"""
Providing a prefilled cache to StreamChangeCache will result in a cache
with the prefilled-cache entered in.
"""
cache = StreamChangeCache("#test", 1, prefilled_cache={"user@foo.com": 2})
self.assertTrue(cache.has_entity_changed("user@foo.com", 1))
def test_has_entity_changed(self):
"""
StreamChangeCache.entity_has_changed will mark entities as changed, and
has_entity_changed will observe the changed entities.
"""
cache = StreamChangeCache("#test", 3)
cache.entity_has_changed("user@foo.com", 6)
cache.entity_has_changed("bar@baz.net", 7)
# also test multiple things changing on the same stream ID
cache.entity_has_changed("user2@foo.com", 8)
cache.entity_has_changed("bar2@baz.net", 8)
# If it's been changed after that stream position, return True
self.assertTrue(cache.has_entity_changed("user@foo.com", 4))
self.assertTrue(cache.has_entity_changed("bar@baz.net", 4))
self.assertTrue(cache.has_entity_changed("bar2@baz.net", 4))
self.assertTrue(cache.has_entity_changed("user2@foo.com", 4))
# If it's been changed at that stream position, return False
self.assertFalse(cache.has_entity_changed("user@foo.com", 6))
self.assertFalse(cache.has_entity_changed("user2@foo.com", 8))
# If there's no changes after that stream position, return False
self.assertFalse(cache.has_entity_changed("user@foo.com", 7))
self.assertFalse(cache.has_entity_changed("user2@foo.com", 9))
# If the entity does not exist, return False.
self.assertFalse(cache.has_entity_changed("not@here.website", 9))
# If we request before the stream cache's earliest known position,
# return True, whether it's a known entity or not.
self.assertTrue(cache.has_entity_changed("user@foo.com", 0))
self.assertTrue(cache.has_entity_changed("not@here.website", 0))
@patch("synapse.util.caches.CACHE_SIZE_FACTOR", 1.0)
def test_entity_has_changed_pops_off_start(self):
"""
StreamChangeCache.entity_has_changed will respect the max size and
purge the oldest items upon reaching that max size.
"""
cache = StreamChangeCache("#test", 1, max_size=2)
cache.entity_has_changed("user@foo.com", 2)
cache.entity_has_changed("bar@baz.net", 3)
cache.entity_has_changed("user@elsewhere.org", 4)
# The cache is at the max size, 2
self.assertEqual(len(cache._cache), 2)
# The oldest item has been popped off
self.assertTrue("user@foo.com" not in cache._entity_to_key)
self.assertEqual(
cache.get_all_entities_changed(2), ["bar@baz.net", "user@elsewhere.org"],
)
self.assertIsNone(cache.get_all_entities_changed(1))
# If we update an existing entity, it keeps the two existing entities
cache.entity_has_changed("bar@baz.net", 5)
self.assertEqual(
{"bar@baz.net", "user@elsewhere.org"}, set(cache._entity_to_key)
)
self.assertEqual(
cache.get_all_entities_changed(2), ["user@elsewhere.org", "bar@baz.net"],
)
self.assertIsNone(cache.get_all_entities_changed(1))
def test_get_all_entities_changed(self):
"""
StreamChangeCache.get_all_entities_changed will return all changed
entities since the given position. If the position is before the start
of the known stream, it returns None instead.
"""
cache = StreamChangeCache("#test", 1)
cache.entity_has_changed("user@foo.com", 2)
cache.entity_has_changed("bar@baz.net", 3)
cache.entity_has_changed("anotheruser@foo.com", 3)
cache.entity_has_changed("user@elsewhere.org", 4)
r = cache.get_all_entities_changed(1)
# either of these are valid
ok1 = [
"user@foo.com",
"bar@baz.net",
"anotheruser@foo.com",
"user@elsewhere.org",
]
ok2 = [
"user@foo.com",
"anotheruser@foo.com",
"bar@baz.net",
"user@elsewhere.org",
]
self.assertTrue(r == ok1 or r == ok2)
r = cache.get_all_entities_changed(2)
self.assertTrue(r == ok1[1:] or r == ok2[1:])
self.assertEqual(cache.get_all_entities_changed(3), ["user@elsewhere.org"])
self.assertEqual(cache.get_all_entities_changed(0), None)
# ... later, things gest more updates
cache.entity_has_changed("user@foo.com", 5)
cache.entity_has_changed("bar@baz.net", 5)
cache.entity_has_changed("anotheruser@foo.com", 6)
ok1 = [
"user@elsewhere.org",
"user@foo.com",
"bar@baz.net",
"anotheruser@foo.com",
]
ok2 = [
"user@elsewhere.org",
"bar@baz.net",
"user@foo.com",
"anotheruser@foo.com",
]
r = cache.get_all_entities_changed(3)
self.assertTrue(r == ok1 or r == ok2)
def test_has_any_entity_changed(self):
"""
StreamChangeCache.has_any_entity_changed will return True if any
entities have been changed since the provided stream position, and
False if they have not. If the cache has entries and the provided
stream position is before it, it will return True, otherwise False if
the cache has no entries.
"""
cache = StreamChangeCache("#test", 1)
# With no entities, it returns False for the past, present, and future.
self.assertFalse(cache.has_any_entity_changed(0))
self.assertFalse(cache.has_any_entity_changed(1))
self.assertFalse(cache.has_any_entity_changed(2))
# We add an entity
cache.entity_has_changed("user@foo.com", 2)
# With an entity, it returns True for the past, the stream start
# position, and False for the stream position the entity was changed
# on and ones after it.
self.assertTrue(cache.has_any_entity_changed(0))
self.assertTrue(cache.has_any_entity_changed(1))
self.assertFalse(cache.has_any_entity_changed(2))
self.assertFalse(cache.has_any_entity_changed(3))
def test_get_entities_changed(self):
"""
StreamChangeCache.get_entities_changed will return the entities in the
given list that have changed since the provided stream ID. If the
stream position is earlier than the earliest known position, it will
return all of the entities queried for.
"""
cache = StreamChangeCache("#test", 1)
cache.entity_has_changed("user@foo.com", 2)
cache.entity_has_changed("bar@baz.net", 3)
cache.entity_has_changed("user@elsewhere.org", 4)
# Query all the entries, but mid-way through the stream. We should only
# get the ones after that point.
self.assertEqual(
cache.get_entities_changed(
["user@foo.com", "bar@baz.net", "user@elsewhere.org"], stream_pos=2
),
{"bar@baz.net", "user@elsewhere.org"},
)
# Query all the entries mid-way through the stream, but include one
# that doesn't exist in it. We shouldn't get back the one that doesn't
# exist.
self.assertEqual(
cache.get_entities_changed(
[
"user@foo.com",
"bar@baz.net",
"user@elsewhere.org",
"not@here.website",
],
stream_pos=2,
),
{"bar@baz.net", "user@elsewhere.org"},
)
# Query all the entries, but before the first known point. We will get
# all the entries we queried for, including ones that don't exist.
self.assertEqual(
cache.get_entities_changed(
[
"user@foo.com",
"bar@baz.net",
"user@elsewhere.org",
"not@here.website",
],
stream_pos=0,
),
{"user@foo.com", "bar@baz.net", "user@elsewhere.org", "not@here.website"},
)
# Query a subset of the entries mid-way through the stream. We should
# only get back the subset.
self.assertEqual(
cache.get_entities_changed(["bar@baz.net"], stream_pos=2), {"bar@baz.net"},
)
def test_max_pos(self):
"""
StreamChangeCache.get_max_pos_of_last_change will return the most
recent point where the entity could have changed. If the entity is not
known, the stream start is provided instead.
"""
cache = StreamChangeCache("#test", 1)
cache.entity_has_changed("user@foo.com", 2)
cache.entity_has_changed("bar@baz.net", 3)
cache.entity_has_changed("user@elsewhere.org", 4)
# Known entities will return the point where they were changed.
self.assertEqual(cache.get_max_pos_of_last_change("user@foo.com"), 2)
self.assertEqual(cache.get_max_pos_of_last_change("bar@baz.net"), 3)
self.assertEqual(cache.get_max_pos_of_last_change("user@elsewhere.org"), 4)
# Unknown entities will return the stream start position.
self.assertEqual(cache.get_max_pos_of_last_change("not@here.website"), 1)