Factor out resolve_state_groups to a separate handler

We extract the storage-independent bits of the state group resolution out to a
separate functiom, and stick it in a new handler, in preparation for its use
from the storage layer.
This commit is contained in:
Richard van der Hoff 2018-01-27 09:15:45 +00:00
parent 0cbda53819
commit 6da4c4d3bd
4 changed files with 108 additions and 54 deletions

View file

@ -81,31 +81,19 @@ class _StateCacheEntry(object):
class StateHandler(object):
""" Responsible for doing state conflict resolution.
"""Fetches bits of state from the stores, and does state resolution
where necessary
"""
def __init__(self, hs):
self.clock = hs.get_clock()
self.store = hs.get_datastore()
self.hs = hs
# dict of set of event_ids -> _StateCacheEntry.
self._state_cache = None
self.resolve_linearizer = Linearizer(name="state_resolve_lock")
self._state_resolution_handler = hs.get_state_resolution_handler()
def start_caching(self):
logger.debug("start_caching")
self._state_cache = ExpiringCache(
cache_name="state_cache",
clock=self.clock,
max_len=SIZE_OF_CACHE,
expiry_ms=EVICTION_TIMEOUT_SECONDS * 1000,
iterable=True,
reset_expiry_on_get=True,
)
self._state_cache.start()
# TODO: remove this shim
self._state_resolution_handler.start_caching()
@defer.inlineCallbacks
def get_current_state(self, room_id, event_type=None, state_key="",
@ -283,7 +271,6 @@ class StateHandler(object):
defer.returnValue(context)
@defer.inlineCallbacks
@log_function
def resolve_state_groups_for_events(self, room_id, event_ids):
""" Given a list of event_ids this method fetches the state at each
event, resolves conflicts between them and returns them.
@ -303,13 +290,7 @@ class StateHandler(object):
room_id, event_ids
)
logger.debug(
"resolve_state_groups state_groups %s",
state_groups_ids.keys()
)
group_names = frozenset(state_groups_ids.keys())
if len(group_names) == 1:
if len(state_groups_ids) == 1:
name, state_list = state_groups_ids.items().pop()
prev_group, delta_ids = yield self.store.get_state_group_delta(name)
@ -321,6 +302,92 @@ class StateHandler(object):
delta_ids=delta_ids,
))
result = yield self._state_resolution_handler.resolve_state_groups(
room_id, state_groups_ids, self._state_map_factory,
)
defer.returnValue(result)
def _state_map_factory(self, ev_ids):
return self.store.get_events(
ev_ids, get_prev_content=False, check_redacted=False,
)
def resolve_events(self, state_sets, event):
logger.info(
"Resolving state for %s with %d groups", event.room_id, len(state_sets)
)
state_set_ids = [{
(ev.type, ev.state_key): ev.event_id
for ev in st
} for st in state_sets]
state_map = {
ev.event_id: ev
for st in state_sets
for ev in st
}
with Measure(self.clock, "state._resolve_events"):
new_state = resolve_events_with_state_map(state_set_ids, state_map)
new_state = {
key: state_map[ev_id] for key, ev_id in new_state.items()
}
return new_state
class StateResolutionHandler(object):
"""Responsible for doing state conflict resolution.
Note that the storage layer depends on this handler, so all functions must
be storage-independent.
"""
def __init__(self, hs):
self.clock = hs.get_clock()
# dict of set of event_ids -> _StateCacheEntry.
self._state_cache = None
self.resolve_linearizer = Linearizer(name="state_resolve_lock")
def start_caching(self):
logger.debug("start_caching")
self._state_cache = ExpiringCache(
cache_name="state_cache",
clock=self.clock,
max_len=SIZE_OF_CACHE,
expiry_ms=EVICTION_TIMEOUT_SECONDS * 1000,
iterable=True,
reset_expiry_on_get=True,
)
self._state_cache.start()
@defer.inlineCallbacks
@log_function
def resolve_state_groups(self, room_id, state_groups_ids, state_map_factory):
"""Resolves conflicts between a set of state groups
Always generates a new state group (unless we hit the cache), so should
not be called for a single state group
Args:
room_id (str): room we are resolving for (used for logging)
state_groups_ids (dict[int, dict[(str, str), str]]):
map from state group id to the state in that state group
(where 'state' is a map from state key to event id)
Returns:
Deferred[_StateCacheEntry]: resolved state
"""
logger.debug(
"resolve_state_groups state_groups %s",
state_groups_ids.keys()
)
group_names = frozenset(state_groups_ids.keys())
with (yield self.resolve_linearizer.queue(group_names)):
if self._state_cache is not None:
cache = self._state_cache.get(group_names, None)
@ -351,15 +418,17 @@ class StateHandler(object):
with Measure(self.clock, "state._resolve_events"):
new_state = yield resolve_events_with_factory(
state_groups_ids.values(),
state_map_factory=lambda ev_ids: self.store.get_events(
ev_ids, get_prev_content=False, check_redacted=False,
),
state_map_factory=state_map_factory,
)
else:
new_state = {
key: e_ids.pop() for key, e_ids in state.items()
}
# if the new state matches any of the input state groups, we can
# use that state group again. Otherwise we will generate a state_id
# which will be used as a cache key for future resolutions, but
# not get persisted.
state_group = None
new_state_event_ids = frozenset(new_state.values())
for sg, events in state_groups_ids.items():
@ -396,30 +465,6 @@ class StateHandler(object):
defer.returnValue(cache)
def resolve_events(self, state_sets, event):
logger.info(
"Resolving state for %s with %d groups", event.room_id, len(state_sets)
)
state_set_ids = [{
(ev.type, ev.state_key): ev.event_id
for ev in st
} for st in state_sets]
state_map = {
ev.event_id: ev
for st in state_sets
for ev in st
}
with Measure(self.clock, "state._resolve_events"):
new_state = resolve_events_with_state_map(state_set_ids, state_map)
new_state = {
key: state_map[ev_id] for key, ev_id in new_state.items()
}
return new_state
def _ordered_events(events):
def key_func(e):