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Refactor event building into EventBuilder

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This is so that everything is done in one place, making it easier to
change the event format based on room version
This commit is contained in:
Erik Johnston 2019-01-25 17:19:31 +00:00
parent 554ca58ea1
commit be47cfa9c9
5 changed files with 257 additions and 115 deletions
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290
synapse/events/builder.py
View file

@ -13,79 +13,156 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import copy
import attr
from synapse.api.constants import RoomVersions
from twisted.internet import defer
from synapse.api.constants import (
KNOWN_EVENT_FORMAT_VERSIONS,
KNOWN_ROOM_VERSIONS,
MAX_DEPTH,
)
from synapse.crypto.event_signing import add_hashes_and_signatures
from synapse.types import EventID
from synapse.util.stringutils import random_string
from . import EventBase, FrozenEvent, _event_dict_property
from . import (
_EventInternalMetadata,
event_type_from_format_version,
room_version_to_event_format,
)
def get_event_builder(room_version, key_values={}, internal_metadata_dict={}):
"""Generate an event builder appropriate for the given room version
@attr.s(slots=True, cmp=False, frozen=True)
class EventBuilder(object):
"""A format independent event builder used to build up the event content
before signing the event.
Args:
room_version (str): Version of the room that we're creating an
event builder for
key_values (dict): Fields used as the basis of the new event
internal_metadata_dict (dict): Used to create the `_EventInternalMetadata`
object.
(Note that while objects of this class are frozen, the
content/unsigned/internal_metadata fields are still mutable)
Returns:
EventBuilder
Attributes:
format_version (int): Event format version
room_id (str)
type (str)
sender (str)
content (dict)
unsigned (dict)
internal_metadata (_EventInternalMetadata)
_state (StateHandler)
_auth (synapse.api.Auth)
_store (DataStore)
_clock (Clock)
_hostname (str): The hostname of the server creating the event
_signing_key: The signing key to use to sign the event as the server
"""
if room_version in {
RoomVersions.V1,
RoomVersions.V2,
RoomVersions.VDH_TEST,
RoomVersions.STATE_V2_TEST,
}:
return EventBuilder(key_values, internal_metadata_dict)
else:
raise Exception(
"No event format defined for version %r" % (room_version,)
_state = attr.ib()
_auth = attr.ib()
_store = attr.ib()
_clock = attr.ib()
_hostname = attr.ib()
_signing_key = attr.ib()
format_version = attr.ib()
room_id = attr.ib()
type = attr.ib()
sender = attr.ib()
content = attr.ib(default=attr.Factory(dict))
unsigned = attr.ib(default=attr.Factory(dict))
# These only exist on a subset of events, so they raise AttributeError if
# someone tries to get them when they don't exist.
_state_key = attr.ib(default=None)
_redacts = attr.ib(default=None)
internal_metadata = attr.ib(default=attr.Factory(lambda: _EventInternalMetadata({})))
@property
def state_key(self):
if self._state_key is not None:
return self._state_key
raise AttributeError("state_key")
def is_state(self):
return self._state_key is not None
@defer.inlineCallbacks
def build(self, prev_event_ids):
"""Transform into a fully signed and hashed event
Args:
prev_event_ids (list[str]): The event IDs to use as the prev events
Returns:
Deferred[FrozenEvent]
"""
state_ids = yield self._state.get_current_state_ids(
self.room_id, prev_event_ids,
)
auth_ids = yield self._auth.compute_auth_events(
self, state_ids,
)
auth_events = yield self._store.add_event_hashes(auth_ids)
prev_events = yield self._store.add_event_hashes(prev_event_ids)
class EventBuilder(EventBase):
def __init__(self, key_values={}, internal_metadata_dict={}):
signatures = copy.deepcopy(key_values.pop("signatures", {}))
unsigned = copy.deepcopy(key_values.pop("unsigned", {}))
super(EventBuilder, self).__init__(
key_values,
signatures=signatures,
unsigned=unsigned,
internal_metadata_dict=internal_metadata_dict,
old_depth = yield self._store.get_max_depth_of(
prev_event_ids,
)
depth = old_depth + 1
event_id = _event_dict_property("event_id")
state_key = _event_dict_property("state_key")
type = _event_dict_property("type")
# we cap depth of generated events, to ensure that they are not
# rejected by other servers (and so that they can be persisted in
# the db)
depth = min(depth, MAX_DEPTH)
def build(self):
return FrozenEvent.from_event(self)
event_dict = {
"auth_events": auth_events,
"prev_events": prev_events,
"type": self.type,
"room_id": self.room_id,
"sender": self.sender,
"content": self.content,
"unsigned": self.unsigned,
"depth": depth,
"prev_state": [],
}
if self.is_state():
event_dict["state_key"] = self._state_key
if self._redacts is not None:
event_dict["redacts"] = self._redacts
defer.returnValue(
create_local_event_from_event_dict(
clock=self._clock,
hostname=self._hostname,
signing_key=self._signing_key,
format_version=self.format_version,
event_dict=event_dict,
internal_metadata_dict=self.internal_metadata.get_dict(),
)
)
class EventBuilderFactory(object):
def __init__(self, clock, hostname):
self.clock = clock
self.hostname = hostname
def __init__(self, hs):
self.clock = hs.get_clock()
self.hostname = hs.hostname
self.signing_key = hs.config.signing_key[0]
self.event_id_count = 0
self.store = hs.get_datastore()
self.state = hs.get_state_handler()
self.auth = hs.get_auth()
def create_event_id(self):
i = str(self.event_id_count)
self.event_id_count += 1
local_part = str(int(self.clock.time())) + i + random_string(5)
e_id = EventID(local_part, self.hostname)
return e_id.to_string()
def new(self, room_version, key_values={}):
def new(self, room_version, key_values):
"""Generate an event builder appropriate for the given room version
Args:
@ -98,27 +175,104 @@ class EventBuilderFactory(object):
"""
# There's currently only the one event version defined
if room_version not in {
RoomVersions.V1,
RoomVersions.V2,
RoomVersions.VDH_TEST,
RoomVersions.STATE_V2_TEST,
}:
if room_version not in KNOWN_ROOM_VERSIONS:
raise Exception(
"No event format defined for version %r" % (room_version,)
)
key_values["event_id"] = self.create_event_id()
key_values["event_id"] = _create_event_id(self.clock, self.hostname)
time_now = int(self.clock.time_msec())
return EventBuilder(
store=self.store,
state=self.state,
auth=self.auth,
clock=self.clock,
hostname=self.hostname,
signing_key=self.signing_key,
format_version=room_version_to_event_format(room_version),
type=key_values["type"],
state_key=key_values.get("state_key"),
room_id=key_values["room_id"],
sender=key_values["sender"],
content=key_values.get("content", {}),
unsigned=key_values.get("unsigned", {}),
redacts=key_values.get("redacts", None),
)
key_values.setdefault("origin", self.hostname)
key_values.setdefault("origin_server_ts", time_now)
key_values.setdefault("unsigned", {})
age = key_values["unsigned"].pop("age", 0)
key_values["unsigned"].setdefault("age_ts", time_now - age)
def create_local_event_from_event_dict(clock, hostname, signing_key,
format_version, event_dict,
internal_metadata_dict=None):
"""Takes a fully formed event dict, ensuring that fields like `origin`
and `origin_server_ts` have correct values for a locally produced event,
then signs and hashes it.
key_values["signatures"] = {}
Args:
clock (Clock)
hostname (str)
signing_key
format_version (int)
event_dict (dict)
internal_metadata_dict (dict|None)
return EventBuilder(key_values=key_values,)
Returns:
FrozenEvent
"""
# There's currently only the one event version defined
if format_version not in KNOWN_EVENT_FORMAT_VERSIONS:
raise Exception(
"No event format defined for version %r" % (format_version,)
)
if internal_metadata_dict is None:
internal_metadata_dict = {}
time_now = int(clock.time_msec())
event_dict["event_id"] = _create_event_id(clock, hostname)
event_dict["origin"] = hostname
event_dict["origin_server_ts"] = time_now
event_dict.setdefault("unsigned", {})
age = event_dict["unsigned"].pop("age", 0)
event_dict["unsigned"].setdefault("age_ts", time_now - age)
event_dict.setdefault("signatures", {})
add_hashes_and_signatures(
event_dict,
hostname,
signing_key,
)
return event_type_from_format_version(format_version)(
event_dict, internal_metadata_dict=internal_metadata_dict,
)
# A counter used when generating new event IDs
_event_id_counter = 0
def _create_event_id(clock, hostname):
"""Create a new event ID
Args:
clock (Clock)
hostname (str): The server name for the event ID
Returns:
str
"""
global _event_id_counter
i = str(_event_id_counter)
_event_id_counter += 1
local_part = str(int(clock.time())) + i + random_string(5)
e_id = EventID(local_part, hostname)
return e_id.to_string()

20
synapse/federation/federation_client.py
View file

@ -37,8 +37,7 @@ from synapse.api.errors import (
HttpResponseException,
SynapseError,
)
from synapse.crypto.event_signing import add_hashes_and_signatures
from synapse.events import room_version_to_event_format
from synapse.events import builder, room_version_to_event_format
from synapse.federation.federation_base import FederationBase, event_from_pdu_json
from synapse.util import logcontext, unwrapFirstError
from synapse.util.caches.expiringcache import ExpiringCache
@ -72,7 +71,8 @@ class FederationClient(FederationBase):
self.state = hs.get_state_handler()
self.transport_layer = hs.get_federation_transport_client()
self.event_builder_factory = hs.get_event_builder_factory()
self.hostname = hs.hostname
self.signing_key = hs.config.signing_key[0]
self._get_pdu_cache = ExpiringCache(
cache_name="get_pdu_cache",
@ -608,18 +608,10 @@ class FederationClient(FederationBase):
if "prev_state" not in pdu_dict:
pdu_dict["prev_state"] = []
# Strip off the fields that we want to clobber.
pdu_dict.pop("origin", None)
pdu_dict.pop("origin_server_ts", None)
pdu_dict.pop("unsigned", None)
builder = self.event_builder_factory.new(room_version, pdu_dict)
add_hashes_and_signatures(
builder,
self.hs.hostname,
self.hs.config.signing_key[0]
ev = builder.create_local_event_from_event_dict(
self._clock, self.hostname, self.signing_key,
format_version=event_format, event_dict=pdu_dict,
)
ev = builder.build()
defer.returnValue(
(destination, ev, event_format)

34
synapse/handlers/message.py
View file

@ -22,7 +22,7 @@ from canonicaljson import encode_canonical_json, json
from twisted.internet import defer
from twisted.internet.defer import succeed
from synapse.api.constants import MAX_DEPTH, EventTypes, Membership, RoomVersions
from synapse.api.constants import EventTypes, Membership, RoomVersions
from synapse.api.errors import (
AuthError,
Codes,
@ -31,7 +31,6 @@ from synapse.api.errors import (
SynapseError,
)
from synapse.api.urls import ConsentURIBuilder
from synapse.crypto.event_signing import add_hashes_and_signatures
from synapse.events.utils import serialize_event
from synapse.events.validator import EventValidator
from synapse.replication.http.send_event import ReplicationSendEventRestServlet
@ -545,40 +544,17 @@ class EventCreationHandler(object):
prev_events_and_hashes = \
yield self.store.get_prev_events_for_room(builder.room_id)
if prev_events_and_hashes:
depth = max([d for _, _, d in prev_events_and_hashes]) + 1
# we cap depth of generated events, to ensure that they are not
# rejected by other servers (and so that they can be persisted in
# the db)
depth = min(depth, MAX_DEPTH)
else:
depth = 1
prev_events = [
(event_id, prev_hashes)
for event_id, prev_hashes, _ in prev_events_and_hashes
]
builder.prev_events = prev_events
builder.depth = depth
context = yield self.state.compute_event_context(builder)
if requester:
context.app_service = requester.app_service
if builder.is_state():
builder.prev_state = yield self.store.add_event_hashes(
context.prev_state_events
)
yield self.auth.add_auth_events(builder, context)
signing_key = self.hs.config.signing_key[0]
add_hashes_and_signatures(
builder, self.server_name, signing_key
event = yield builder.build(
prev_event_ids=[p for p, _ in prev_events],
)
context = yield self.state.compute_event_context(event)
event = builder.build()
self.validator.validate_new(event)
logger.debug(
"Created event %s",

5
synapse/server.py
View file

@ -355,10 +355,7 @@ class HomeServer(object):
return Keyring(self)
def build_event_builder_factory(self):
return EventBuilderFactory(
clock=self.get_clock(),
hostname=self.hostname,
)
return EventBuilderFactory(self)
def build_filtering(self):
return Filtering(self)

23
synapse/storage/event_federation.py
View file

@ -125,6 +125,29 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
return dict(txn)
@defer.inlineCallbacks
def get_max_depth_of(self, event_ids):
"""Returns the max depth of a set of event IDs
Args:
event_ids (list[str])
Returns
Deferred[int]
"""
rows = yield self._simple_select_many_batch(
table="events",
column="event_id",
iterable=event_ids,
retcols=("depth",),
desc="get_max_depth_of",
)
if not rows:
defer.returnValue(0)
else:
defer.returnValue(max(row["depth"] for row in rows))
def _get_oldest_events_in_room_txn(self, txn, room_id):
return self._simple_select_onecol_txn(
txn,