synapse/synapse/handlers/appservice.py

# Copyright 2015, 2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from typing import TYPE_CHECKING, Collection, Dict, Iterable, List, Optional, Union

from prometheus_client import Counter

from twisted.internet import defer

import synapse
from synapse.api.constants import EventTypes
from synapse.appservice import ApplicationService
from synapse.events import EventBase
from synapse.handlers.presence import format_user_presence_state
from synapse.logging.context import make_deferred_yieldable, run_in_background
from synapse.metrics import (
    event_processing_loop_counter,
    event_processing_loop_room_count,
)
from synapse.metrics.background_process_metrics import (
    run_as_background_process,
    wrap_as_background_process,
)
from synapse.storage.databases.main.directory import RoomAliasMapping
from synapse.types import JsonDict, RoomAlias, RoomStreamToken, UserID
from synapse.util.metrics import Measure

if TYPE_CHECKING:
    from synapse.server import HomeServer

logger = logging.getLogger(__name__)

events_processed_counter = Counter("synapse_handlers_appservice_events_processed", "")


class ApplicationServicesHandler:
    def __init__(self, hs: "HomeServer"):
        self.store = hs.get_datastore()
        self.is_mine_id = hs.is_mine_id
        self.appservice_api = hs.get_application_service_api()
        self.scheduler = hs.get_application_service_scheduler()
        self.started_scheduler = False
        self.clock = hs.get_clock()
        self.notify_appservices = hs.config.appservice.notify_appservices
        self.event_sources = hs.get_event_sources()

        self.current_max = 0
        self.is_processing = False

    def notify_interested_services(self, max_token: RoomStreamToken) -> None:
        """Notifies (pushes) all application services interested in this event.

        Pushing is done asynchronously, so this method won't block for any
        prolonged length of time.
        """
        # We just use the minimum stream ordering and ignore the vector clock
        # component. This is safe to do as long as we *always* ignore the vector
        # clock components.
        current_id = max_token.stream

        services = self.store.get_app_services()
        if not services or not self.notify_appservices:
            return

        self.current_max = max(self.current_max, current_id)
        if self.is_processing:
            return

        # We only start a new background process if necessary rather than
        # optimistically (to cut down on overhead).
        self._notify_interested_services(max_token)

    @wrap_as_background_process("notify_interested_services")
    async def _notify_interested_services(self, max_token: RoomStreamToken) -> None:
        with Measure(self.clock, "notify_interested_services"):
            self.is_processing = True
            try:
                limit = 100
                upper_bound = -1
                while upper_bound < self.current_max:
                    (
                        upper_bound,
                        events,
                    ) = await self.store.get_new_events_for_appservice(
                        self.current_max, limit
                    )

                    events_by_room: Dict[str, List[EventBase]] = {}
                    for event in events:
                        events_by_room.setdefault(event.room_id, []).append(event)

                    async def handle_event(event: EventBase) -> None:
                        # Gather interested services
                        services = await self._get_services_for_event(event)
                        if len(services) == 0:
                            return  # no services need notifying

                        # Do we know this user exists? If not, poke the user
                        # query API for all services which match that user regex.
                        # This needs to block as these user queries need to be
                        # made BEFORE pushing the event.
                        await self._check_user_exists(event.sender)
                        if event.type == EventTypes.Member:
                            await self._check_user_exists(event.state_key)

                        if not self.started_scheduler:

                            async def start_scheduler() -> None:
                                try:
                                    await self.scheduler.start()
                                except Exception:
                                    logger.error("Application Services Failure")

                            run_as_background_process("as_scheduler", start_scheduler)
                            self.started_scheduler = True

                        # Fork off pushes to these services
                        for service in services:
                            self.scheduler.submit_event_for_as(service, event)

                        now = self.clock.time_msec()
                        ts = await self.store.get_received_ts(event.event_id)
                        assert ts is not None

                        synapse.metrics.event_processing_lag_by_event.labels(
                            "appservice_sender"
                        ).observe((now - ts) / 1000)

                    async def handle_room_events(events: Iterable[EventBase]) -> None:
                        for event in events:
                            await handle_event(event)

                    await make_deferred_yieldable(
                        defer.gatherResults(
                            [
                                run_in_background(handle_room_events, evs)
                                for evs in events_by_room.values()
                            ],
                            consumeErrors=True,
                        )
                    )

                    await self.store.set_appservice_last_pos(upper_bound)

                    synapse.metrics.event_processing_positions.labels(
                        "appservice_sender"
                    ).set(upper_bound)

                    events_processed_counter.inc(len(events))

                    event_processing_loop_room_count.labels("appservice_sender").inc(
                        len(events_by_room)
                    )

                    event_processing_loop_counter.labels("appservice_sender").inc()

                    if events:
                        now = self.clock.time_msec()
                        ts = await self.store.get_received_ts(events[-1].event_id)
                        assert ts is not None

                        synapse.metrics.event_processing_lag.labels(
                            "appservice_sender"
                        ).set(now - ts)
                        synapse.metrics.event_processing_last_ts.labels(
                            "appservice_sender"
                        ).set(ts)
            finally:
                self.is_processing = False

    def notify_interested_services_ephemeral(
        self,
        stream_key: str,
        new_token: Optional[int],
        users: Collection[Union[str, UserID]],
    ) -> None:
        """
        This is called by the notifier in the background when
        an ephemeral event is handled by the homeserver.

        This will determine which appservices are
        interested in the event, and submit them.

        Args:
            stream_key: The stream the event came from.

                When `stream_key` is "typing_key", "receipt_key" or "presence_key", events
                will only be pushed to appservices that have opted into ephemeral events.
                Appservices will only receive ephemeral events that fall within their
                registered user and room namespaces.

                TODO: Update this bit

                Any other value for `stream_key` will cause this function to return early.

            new_token: The latest stream token.
            users: The users that should be informed of the new event, if any.
        """
        if not self.notify_appservices:
            return

        if stream_key in ("typing_key", "receipt_key", "presence_key"):
            # Check whether there are any appservices which have registered to receive
            # ephemeral events.
            #
            # Note that whether these events are actually relevant to these appservices
            # is decided later on.
            services = [
                service
                for service in self.store.get_app_services()
                if service.supports_ephemeral
            ]
            if not services:
                # Bail out early if none of the target appservices have explicitly registered
                # to receive these ephemeral events.
                return

        elif stream_key == "to_device_key":
            # Appservices do not need to register explicit support for receiving device list
            # updates.
            #
            # Note that whether these events are actually relevant to these appservices is
            # decided later on.
            services = self.store.get_app_services()

        else:
            # This stream_key is not supported.
            return

        # We only start a new background process if necessary rather than
        # optimistically (to cut down on overhead).
        self._notify_interested_services_ephemeral(
            services, stream_key, new_token, users
        )

    @wrap_as_background_process("notify_interested_services_ephemeral")
    async def _notify_interested_services_ephemeral(
        self,
        services: List[ApplicationService],
        stream_key: str,
        new_token: Optional[int],
        users: Collection[Union[str, UserID]],
    ) -> None:
        logger.debug("Checking interested services for %s" % stream_key)
        with Measure(self.clock, "notify_interested_services_ephemeral"):
            for service in services:
                # Only handle typing if we have the latest token
                if stream_key == "typing_key" and new_token is not None:
                    # Note that we don't persist the token (via set_type_stream_id_for_appservice)
                    # for typing_key due to performance reasons and due to their highly
                    # ephemeral nature.
                    #
                    # Instead we simply grab the latest typing update in _handle_typing
                    # and, if it applies to this application service, send it off.
                    events = await self._handle_typing(service, new_token)
                    if events:
                        self.scheduler.submit_ephemeral_events_for_as(service, events)

                elif stream_key == "receipt_key":
                    events = await self._handle_receipts(service)
                    if events:
                        self.scheduler.submit_ephemeral_events_for_as(service, events)

                    # Persist the latest handled stream token for this appservice
                    # TODO: We seem to update the stream token for each appservice,
                    #  even if sending the ephemeral events to the appservice failed.
                    # This is expected for typing, receipt and presence, but will need
                    # to be handled for device* streams.
                    await self.store.set_type_stream_id_for_appservice(
                        service, "read_receipt", new_token
                    )

                elif stream_key == "presence_key":
                    events = await self._handle_presence(service, users)
                    if events:
                        self.scheduler.submit_ephemeral_events_for_as(service, events)

                    # Persist the latest handled stream token for this appservice
                    await self.store.set_type_stream_id_for_appservice(
                        service, "presence", new_token
                    )

                elif stream_key == "to_device_key" and new_token is not None:
                    events = await self._handle_to_device(service, new_token, users)
                    if events:
                        self.scheduler.submit_ephemeral_events_for_as(service, events)

                    # Persist the latest handled stream token for this appservice
                    await self.store.set_type_stream_id_for_appservice(
                        service, "to_device", new_token
                    )

    async def _handle_to_device(
        self,
        service: ApplicationService,
        new_token: int,
        users: Collection[Union[str, UserID]],
    ) -> List[JsonDict]:
        """
        Given an application service, determine which events it should receive
        from those between the last-recorded typing event stream token for this
        appservice and the given stream token.

        Args:
            service: The application service to check for which events it should receive.
            new_token: The latest to-device event stream token.
            users: The users that should receive new to-device messages.

        Returns:
            A list of JSON dictionaries containing data derived from the typing events that
            should be sent to the given application service.
        """
        # Get the stream token that this application service has processed up until
        from_key = await self.store.get_type_stream_id_for_appservice(
            service, "to_device"
        )

        # Filter out users that this appservice is not interested in
        users_appservice_is_interested_in: List[str] = []
        for user in users:
            if isinstance(user, UserID):
                user = user.to_string()

            if service.is_interested_in_user(user):
                users_appservice_is_interested_in.append(user)

        if not users_appservice_is_interested_in:
            # Return early if the AS was not interested in any of these users
            return []

        # Retrieve the to-device messages for each user
        (
            recipient_user_id_device_id_to_messages,
            max_stream_token,
        ) = await self.store.get_new_messages(
            users_appservice_is_interested_in, from_key, new_token, limit=100
        )

        logger.info(
            "*** Users: %s, from: %s, to: %s",
            users_appservice_is_interested_in,
            from_key,
            new_token,
        )
        logger.info(
            "*** Got to-device message: %s", recipient_user_id_device_id_to_messages
        )

        # TODO: Keep pulling out if max_stream_token != new_token?

        # According to MSC2409, we'll need to add 'to_user_id' and 'to_device_id' fields
        # to the event JSON so that the application service will know which user/device
        # combination this messages was intended for.
        #
        # So we mangle this dict into a flat list of to-device messages with the relevant
        # user ID and device ID embedded inside each message dict.
        message_payload: List[JsonDict] = []
        for (
            user_id,
            device_id,
        ), messages in recipient_user_id_device_id_to_messages.items():
            for message_json in messages:
                # Remove 'message_id' from the to-device message, as it's an internal ID
                message_json.pop("message_id", None)

                message_payload.append(
                    {
                        "to_user_id": user_id,
                        "to_device_id": device_id,
                        **message_json,
                    }
                )

        logger.info("*** Ended up with messages: %s", message_payload)

        return message_payload

    async def _handle_typing(
        self, service: ApplicationService, new_token: int
    ) -> List[JsonDict]:
        """
        Given an application service, determine which events it should receive
        from the given typing event stream token and now.

        Args:
            service: The application service to check for which events it should receive.
            new_token: The latest typing event stream token.

        Returns:
            A list of JSON dictionaries containing data derived from the typing events that
            should be sent to the given application service.
        """
        typing_source = self.event_sources.sources.typing
        # Get the typing events from just before current
        typing, _ = await typing_source.get_new_events_as(
            service=service,
            # For performance reasons, we don't persist the previous
            # token in the DB and instead fetch the latest typing event
            # for appservices.
            # TODO: It'd probably be more efficient to simply fetch the
            #  typing event with the given 'new_token' stream token and
            #  checking if the given service was interested, rather than
            #  iterating over all typing events and only grabbing the
            #  latest one.
            from_key=new_token - 1,
        )
        return typing

    async def _handle_receipts(self, service: ApplicationService) -> List[JsonDict]:
        """
        Given an application service, determine which events it should receive
        from those between the last-recorded typing event stream token for this
        appservice and the latest one.

        Args:
            service: The application service to check for which events it should receive.
            new_token: A typing event stream token. Typing events between this token and
                the current event stream token will be checked.

        Returns:
            A list of JSON dictionaries containing data derived from the typing events that
            should be sent to the given application service.
        """
        from_key = await self.store.get_type_stream_id_for_appservice(
            service, "read_receipt"
        )
        receipts_source = self.event_sources.sources.receipt
        receipts, _ = await receipts_source.get_new_events_as(
            service=service, from_key=from_key
        )
        return receipts

    async def _handle_presence(
        self, service: ApplicationService, users: Collection[Union[str, UserID]]
    ) -> List[JsonDict]:
        """
        Given an application service and a list of users who should be receiving
        presence updates, return a list of presence updates destined for the
        application service.

        Args:
            service: The application service that ephemeral events are being sent to.
            users: The users that should receive the presence update.

        Returns:
            A list of json dictionaries containing data derived from the presence events
            that should be sent to the given application service.
        """
        events: List[JsonDict] = []
        presence_source = self.event_sources.sources.presence
        from_key = await self.store.get_type_stream_id_for_appservice(
            service, "presence"
        )
        for user in users:
            if isinstance(user, str):
                user = UserID.from_string(user)

            interested = await service.is_interested_in_presence(user, self.store)
            if not interested:
                continue
            presence_events, _ = await presence_source.get_new_events(
                user=user,
                service=service,
                from_key=from_key,
            )
            time_now = self.clock.time_msec()
            events.extend(
                {
                    "type": "m.presence",
                    "sender": event.user_id,
                    "content": format_user_presence_state(
                        event, time_now, include_user_id=False
                    ),
                }
                for event in presence_events
            )

        return events

    async def query_user_exists(self, user_id: str) -> bool:
        """Check if any application service knows this user_id exists.

        Args:
            user_id: The user to query if they exist on any AS.
        Returns:
            True if this user exists on at least one application service.
        """
        user_query_services = self._get_services_for_user(user_id=user_id)
        for user_service in user_query_services:
            is_known_user = await self.appservice_api.query_user(user_service, user_id)
            if is_known_user:
                return True
        return False

    async def query_room_alias_exists(
        self, room_alias: RoomAlias
    ) -> Optional[RoomAliasMapping]:
        """Check if an application service knows this room alias exists.

        Args:
            room_alias: The room alias to query.
        Returns:
            namedtuple: with keys "room_id" and "servers" or None if no
            association can be found.
        """
        room_alias_str = room_alias.to_string()
        services = self.store.get_app_services()
        alias_query_services = [
            s for s in services if (s.is_interested_in_alias(room_alias_str))
        ]
        for alias_service in alias_query_services:
            is_known_alias = await self.appservice_api.query_alias(
                alias_service, room_alias_str
            )
            if is_known_alias:
                # the alias exists now so don't query more ASes.
                return await self.store.get_association_from_room_alias(room_alias)

        return None

    async def query_3pe(
        self, kind: str, protocol: str, fields: Dict[bytes, List[bytes]]
    ) -> List[JsonDict]:
        services = self._get_services_for_3pn(protocol)

        results = await make_deferred_yieldable(
            defer.DeferredList(
                [
                    run_in_background(
                        self.appservice_api.query_3pe, service, kind, protocol, fields
                    )
                    for service in services
                ],
                consumeErrors=True,
            )
        )

        ret = []
        for (success, result) in results:
            if success:
                ret.extend(result)

        return ret

    async def get_3pe_protocols(
        self, only_protocol: Optional[str] = None
    ) -> Dict[str, JsonDict]:
        services = self.store.get_app_services()
        protocols: Dict[str, List[JsonDict]] = {}

        # Collect up all the individual protocol responses out of the ASes
        for s in services:
            for p in s.protocols:
                if only_protocol is not None and p != only_protocol:
                    continue

                if p not in protocols:
                    protocols[p] = []

                info = await self.appservice_api.get_3pe_protocol(s, p)

                if info is not None:
                    protocols[p].append(info)

        def _merge_instances(infos: List[JsonDict]) -> JsonDict:
            # Merge the 'instances' lists of multiple results, but just take
            # the other fields from the first as they ought to be identical
            # copy the result so as not to corrupt the cached one
            combined = dict(infos[0])
            combined["instances"] = list(combined["instances"])

            for info in infos[1:]:
                combined["instances"].extend(info["instances"])

            return combined

        return {
            p: _merge_instances(protocols[p]) for p in protocols.keys() if protocols[p]
        }

    async def _get_services_for_event(
        self, event: EventBase
    ) -> List[ApplicationService]:
        """Retrieve a list of application services interested in this event.

        Args:
            event: The event to check. Can be None if alias_list is not.
        Returns:
            A list of services interested in this event based on the service regex.
        """
        services = self.store.get_app_services()

        # we can't use a list comprehension here. Since python 3, list
        # comprehensions use a generator internally. This means you can't yield
        # inside of a list comprehension anymore.
        interested_list = []
        for s in services:
            if await s.is_interested(event, self.store):
                interested_list.append(s)

        return interested_list

    def _get_services_for_user(self, user_id: str) -> List[ApplicationService]:
        services = self.store.get_app_services()
        return [s for s in services if (s.is_interested_in_user(user_id))]

    def _get_services_for_3pn(self, protocol: str) -> List[ApplicationService]:
        services = self.store.get_app_services()
        return [s for s in services if s.is_interested_in_protocol(protocol)]

    async def _is_unknown_user(self, user_id: str) -> bool:
        if not self.is_mine_id(user_id):
            # we don't know if they are unknown or not since it isn't one of our
            # users. We can't poke ASes.
            return False

        user_info = await self.store.get_user_by_id(user_id)
        if user_info:
            return False

        # user not found; could be the AS though, so check.
        services = self.store.get_app_services()
        service_list = [s for s in services if s.sender == user_id]
        return len(service_list) == 0

    async def _check_user_exists(self, user_id: str) -> bool:
        unknown_user = await self._is_unknown_user(user_id)
        if unknown_user:
            return await self.query_user_exists(user_id)
        return True