summary refs log tree commit diff
path: root/synapse/storage/stream.py
blob: 475e7f20a16090f298afb8070079c6d8a10d541a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
# -*- coding: utf-8 -*-
# Copyright 2014 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.

""" This module is responsible for getting events from the DB for pagination
and event streaming.

The order it returns events in depend on whether we are streaming forwards or
are paginating backwards. We do this because we want to handle out of order
messages nicely, while still returning them in the correct order when we
paginate bacwards.

This is implemented by keeping two ordering columns: stream_ordering and
topological_ordering. Stream ordering is basically insertion/received order
(except for events from backfill requests). The topolgical_ordering is a
weak ordering of events based on the pdu graph.

This means that we have to have two different types of tokens, depending on
what sort order was used:
    - stream tokens are of the form: "s%d", which maps directly to the column
    - topological tokems: "t%d-%d", where the integers map to the topological
      and stream ordering columns respectively.
"""

from twisted.internet import defer

from ._base import SQLBaseStore
from synapse.api.errors import SynapseError
from synapse.util.logutils import log_function

import logging


logger = logging.getLogger(__name__)


MAX_STREAM_SIZE = 1000


_STREAM_TOKEN = "stream"
_TOPOLOGICAL_TOKEN = "topological"


def _parse_stream_token(string):
    try:
        if string[0] != 's':
            raise
        return int(string[1:])
    except:
        raise SynapseError(400, "Invalid token")


def _parse_topological_token(string):
    try:
        if string[0] != 't':
            raise
        parts = string[1:].split('-', 1)
        return (int(parts[0]), int(parts[1]))
    except:
        raise SynapseError(400, "Invalid token")


def is_stream_token(string):
    try:
        _parse_stream_token(string)
        return True
    except:
        return False


def is_topological_token(string):
    try:
        _parse_topological_token(string)
        return True
    except:
        return False


def _get_token_bound(token, comparison):
    try:
        s = _parse_stream_token(token)
        return "%s %s %d" % ("stream_ordering", comparison, s)
    except:
        pass

    try:
        top, stream = _parse_topological_token(token)
        return "%s %s %d AND %s %s %d" % (
            "topological_ordering", comparison, top,
            "stream_ordering", comparison, stream,
        )
    except:
        pass

    raise SynapseError(400, "Invalid token")


class StreamStore(SQLBaseStore):
    @log_function
    def get_room_events(self, user_id, from_key, to_key, room_id, limit=0,
                        direction='f', with_feedback=False):
        # We deal with events request in two different ways depending on if
        # this looks like an /events request or a pagination request.
        is_events = (
            direction == 'f'
            and user_id
            and is_stream_token(from_key)
            and to_key and is_stream_token(to_key)
        )

        if is_events:
            return self.get_room_events_stream(
                user_id=user_id,
                from_key=from_key,
                to_key=to_key,
                room_id=room_id,
                limit=limit,
                with_feedback=with_feedback,
            )
        else:
            return self.paginate_room_events(
                from_key=from_key,
                to_key=to_key,
                room_id=room_id,
                limit=limit,
                with_feedback=with_feedback,
            )

    @defer.inlineCallbacks
    @log_function
    def get_room_events_stream(self, user_id, from_key, to_key, room_id,
                               limit=0, with_feedback=False):
        # TODO (erikj): Handle compressed feedback

        current_room_membership_sql = (
            "SELECT m.room_id FROM room_memberships as m "
            "INNER JOIN current_state_events as c ON m.event_id = c.event_id "
            "WHERE m.user_id = ? AND m.membership = 'join'"
        )

        # We also want to get any membership events about that user, e.g.
        # invites or leave notifications.
        membership_sql = (
            "SELECT m.event_id FROM room_memberships as m "
            "INNER JOIN current_state_events as c ON m.event_id = c.event_id "
            "WHERE m.user_id = ? "
        )

        del_sql = (
            "SELECT event_id FROM redactions WHERE redacts = e.event_id "
            "LIMIT 1"
        )

        if limit:
            limit = max(limit, MAX_STREAM_SIZE)
        else:
            limit = MAX_STREAM_SIZE

        # From and to keys should be integers from ordering.
        from_id = _parse_stream_token(from_key)
        to_id = _parse_stream_token(to_key)

        if from_key == to_key:
            defer.returnValue(([], to_key))
            return

        sql = (
            "SELECT *, (%(redacted)s) AS redacted FROM events AS e WHERE "
            "(e.outlier = 0 AND (room_id IN (%(current)s)) OR "
            "(event_id IN (%(invites)s))) "
            "AND e.stream_ordering > ? AND e.stream_ordering <= ? "
            "ORDER BY stream_ordering ASC LIMIT %(limit)d "
        ) % {
            "redacted": del_sql,
            "current": current_room_membership_sql,
            "invites": membership_sql,
            "limit": limit
        }

        rows = yield self._execute_and_decode(
            sql,
            user_id, user_id, from_id, to_id
        )

        ret = yield self._parse_events(rows)

        if rows:
            key = "s%d" % max([r["stream_ordering"] for r in rows])
        else:
            # Assume we didn't get anything because there was nothing to get.
            key = to_key

        defer.returnValue((ret, key))

    @defer.inlineCallbacks
    @log_function
    def paginate_room_events(self, room_id, from_key, to_key=None,
                             direction='b', limit=-1,
                             with_feedback=False):
        # TODO (erikj): Handle compressed feedback

        # Tokens really represent positions between elements, but we use
        # the convention of pointing to the event before the gap. Hence
        # we have a bit of asymmetry when it comes to equalities.
        from_comp = '<=' if direction =='b' else '>'
        to_comp = '>' if direction =='b' else '<='
        order = "DESC" if direction == 'b' else "ASC"

        args = [room_id]

        bounds = _get_token_bound(from_key, from_comp)
        if to_key:
            bounds = "%s AND %s" % (bounds, _get_token_bound(to_key, to_comp))

        if int(limit) > 0:
            args.append(int(limit))
            limit_str = " LIMIT ?"
        else:
            limit_str = ""

        del_sql = (
            "SELECT event_id FROM redactions WHERE redacts = events.event_id "
            "LIMIT 1"
        )

        sql = (
            "SELECT *, (%(redacted)s) AS redacted FROM events "
            "WHERE outlier = 0 AND room_id = ? AND %(bounds)s "
            "ORDER BY topological_ordering %(order)s, stream_ordering %(order)s %(limit)s "
        ) % {
            "redacted": del_sql,
            "bounds": bounds,
            "order": order,
            "limit": limit_str
        }

        rows = yield self._execute_and_decode(
            sql,
            *args
        )

        if rows:
            topo = rows[-1]["topological_ordering"]
            toke = rows[-1]["stream_ordering"]
            next_token = "t%s-%s" % (topo, toke)
        else:
            # TODO (erikj): We should work out what to do here instead.
            next_token = to_key if to_key else from_key

        events = yield self._parse_events(rows)

        defer.returnValue(
            (
                events,
                next_token
            )
        )

    @defer.inlineCallbacks
    def get_recent_events_for_room(self, room_id, limit, end_token,
                                   with_feedback=False):
        # TODO (erikj): Handle compressed feedback

        del_sql = (
            "SELECT event_id FROM redactions WHERE redacts = events.event_id "
            "LIMIT 1"
        )

        sql = (
            "SELECT *, (%(redacted)s) AS redacted FROM events "
            "WHERE room_id = ? AND stream_ordering <= ? "
            "ORDER BY topological_ordering DESC, stream_ordering DESC LIMIT ? "
        ) % {
            "redacted": del_sql,
        }

        rows = yield self._execute_and_decode(
            sql,
            room_id, end_token, limit
        )

        rows.reverse()  # As we selected with reverse ordering

        if rows:
            topo = rows[0]["topological_ordering"]
            toke = rows[0]["stream_ordering"]
            start_token = "t%s-%s" % (topo, toke)

            token = (start_token, end_token)
        else:
            token = (end_token, end_token)

        events = yield self._parse_events(rows)

        ret = (events, token)

        defer.returnValue(ret)

    def get_room_events_max_id(self):
        return self.runInteraction(
            "get_room_events_max_id",
            self._get_room_events_max_id_txn
        )

    def _get_room_events_max_id_txn(self, txn):
        txn.execute(
            "SELECT MAX(stream_ordering) as m FROM events"
        )

        res = self.cursor_to_dict(txn)

        logger.debug("get_room_events_max_id: %s", res)

        if not res or not res[0] or not res[0]["m"]:
            return "s0"

        key = res[0]["m"]
        return "s%d" % (key,)