Make EventContext lazy load state

This commit is contained in:
Erik Johnston 2018-07-23 12:38:46 +01:00
parent 842cdece42
commit 440b8845b5
2 changed files with 115 additions and 44 deletions

View File

@ -19,18 +19,12 @@ from frozendict import frozendict
from twisted.internet import defer
from synapse.util.logcontext import make_deferred_yieldable, run_in_background
class EventContext(object):
"""
Attributes:
current_state_ids (dict[(str, str), str]):
The current state map including the current event.
(type, state_key) -> event_id
prev_state_ids (dict[(str, str), str]):
The current state map excluding the current event.
(type, state_key) -> event_id
state_group (int|None): state group id, if the state has been stored
as a state group. This is usually only None if e.g. the event is
an outlier.
@ -47,36 +41,71 @@ class EventContext(object):
prev_state_events (?): XXX: is this ever set to anything other than
the empty list?
_current_state_ids (dict[(str, str), str]|None):
The current state map including the current event. None if outlier
or we haven't fetched the state from DB yet.
(type, state_key) -> event_id
_prev_state_ids (dict[(str, str), str]|None):
The current state map excluding the current event. None if outlier
or we haven't fetched the state from DB yet.
(type, state_key) -> event_id
_fetching_state_deferred (Deferred|None): Resolves when *_state_ids have
been calculated. None if we haven't started calculating yet
_prev_state_id (str|None): If set then the event associated with the
context overrode the _prev_state_id
_event_type (str): The type of the event the context is associated with
_event_state_key (str|None): The state_key of the event the context is
associated with
"""
__slots__ = [
"current_state_ids",
"prev_state_ids",
"state_group",
"rejected",
"prev_group",
"delta_ids",
"prev_state_events",
"app_service",
"_current_state_ids",
"_prev_state_ids",
"_prev_state_id",
"_event_type",
"_event_state_key",
"_fetching_state_deferred",
]
def __init__(self, state_group, current_state_ids, prev_state_ids,
@staticmethod
def with_state(state_group, current_state_ids, prev_state_ids,
prev_group=None, delta_ids=None):
context = EventContext()
# The current state including the current event
self.current_state_ids = current_state_ids
context._current_state_ids = current_state_ids
# The current state excluding the current event
self.prev_state_ids = prev_state_ids
self.state_group = state_group
context._prev_state_ids = prev_state_ids
context.state_group = state_group
context._prev_state_id = None
context._event_type = None
context._event_state_key = None
context._fetching_state_deferred = defer.succeed(None)
# A previously persisted state group and a delta between that
# and this state.
self.prev_group = prev_group
self.delta_ids = delta_ids
context.prev_group = prev_group
context.delta_ids = delta_ids
self.prev_state_events = []
context.prev_state_events = []
self.rejected = False
self.app_service = None
context.rejected = False
context.app_service = None
return context
def serialize(self, event):
"""Converts self to a type that can be serialized as JSON, and then
@ -123,30 +152,17 @@ class EventContext(object):
Returns:
EventContext
"""
context = EventContext()
# We use the state_group and prev_state_id stuff to pull the
# current_state_ids out of the DB and construct prev_state_ids.
prev_state_id = input["prev_state_id"]
event_type = input["event_type"]
event_state_key = input["event_state_key"]
context._prev_state_id = input["prev_state_id"]
context._event_type = input["event_type"]
context._event_state_key = input["event_state_key"]
state_group = input["state_group"]
current_state_ids = yield store.get_state_ids_for_group(
state_group,
)
if prev_state_id and event_state_key:
prev_state_ids = dict(current_state_ids)
prev_state_ids[(event_type, event_state_key)] = prev_state_id
else:
prev_state_ids = current_state_ids
context = EventContext(
state_group=state_group,
current_state_ids=current_state_ids,
prev_state_ids=prev_state_ids,
prev_group=input["prev_group"],
delta_ids=_decode_state_dict(input["delta_ids"]),
)
context.state_group = input["state_group"]
context.prev_group = input["prev_group"]
context.delta_ids = _decode_state_dict(input["delta_ids"])
context.rejected = input["rejected"]
context.prev_state_events = input["prev_state_events"]
@ -157,6 +173,61 @@ class EventContext(object):
defer.returnValue(context)
@defer.inlineCallbacks
def get_current_state_ids(self, store):
"""Gets the current state IDs
Returns:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
is None, which happens when the associated event is an outlier.
"""
if not self._fetching_state_deferred:
self._fetching_state_deferred = run_in_background(
self._fill_out_state, store,
)
yield make_deferred_yieldable(self._fetching_state_deferred)
defer.returnValue(self._current_state_ids)
@defer.inlineCallbacks
def get_prev_state_ids(self, store):
"""Gets the prev state IDs
Returns:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
is None, which happens when the associated event is an outlier.
"""
if not self._fetching_state_deferred:
self._fetching_state_deferred = run_in_background(
self._fill_out_state, store,
)
yield make_deferred_yieldable(self._fetching_state_deferred)
defer.returnValue(self._prev_state_ids)
@defer.inlineCallbacks
def _fill_out_state(self, store):
"""Called to populate the _current_state_ids and _prev_state_ids
attributes by loading from the database.
"""
if self.state_group is None:
return
self._current_state_ids = yield store.get_state_ids_for_group(
self.state_group,
)
if self._prev_state_id and self._event_state_key is not None:
self._prev_state_ids = dict(self._current_state_ids)
key = (self._event_type, self._event_state_key)
self._prev_state_ids[key] = self._prev_state_id
else:
self._prev_state_ids = self._current_state_ids
def _encode_state_dict(state_dict):
"""Since dicts of (type, state_key) -> event_id cannot be serialized in

View File

@ -219,7 +219,7 @@ class StateHandler(object):
# We don't store state for outliers, so we don't generate a state
# group for it.
context = EventContext(
context = EventContext.with_state(
state_group=None,
current_state_ids=current_state_ids,
prev_state_ids=prev_state_ids,
@ -255,7 +255,7 @@ class StateHandler(object):
current_state_ids=current_state_ids,
)
context = EventContext(
context = EventContext.with_state(
state_group=state_group,
current_state_ids=current_state_ids,
prev_state_ids=prev_state_ids,
@ -322,7 +322,7 @@ class StateHandler(object):
state_group = entry.state_group
context = EventContext(
context = EventContext.with_state(
state_group=state_group,
current_state_ids=current_state_ids,
prev_state_ids=prev_state_ids,