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Initial TCP protocol implementation
This defines the low level TCP replication protocol
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docs/tcp_replication.rst
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docs/tcp_replication.rst
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TCP Replication
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===============
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This describes the TCP replication protocol that replaces the HTTP protocol.
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Motivation
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----------
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The HTTP API used long poll from the workers to the master, this has the problem
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of causing a lot of duplicate work on the server. This TCP protocol aims to
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solve.
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Overview
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--------
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The protocol is based on fire and forget, line based commands. An example flow
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would be (where '>' indicates master->worker and '<' worker->master flows)::
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> SERVER example.com
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< REPLICATE events 53
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> RDATA events 54 ["$foo1:bar.com", ...]
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> RDATA events 55 ["$foo4:bar.com", ...]
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The example shows the server accepting a new connection and sending its identity
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with the ``SERVER`` command, followed by the client asking to subscribe to the
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``events`` stream from the token ``53``. The server then periodically sends ``RDATA``
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commands which have the format ``RDATA <stream_name> <token> <row>```, where the
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format of ``<row>`` is defined by the individual streams.
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Error reporting happens by either the client or server sending an `ERROR`
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command, and usually the connection will be closed.
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Since the protocol is a simple line based, its possible to manually connect to
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the server using a tool like netcat. A few things should be noted when manually
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using the protocol:
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* When subscribing to a stream using ``REPLICATE``, the special token ``NOW`` can
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be used to get all future updates. The special stream name ``ALL`` can be used
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with ``NOW`` to subscribe to all available streams.
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* The federation stream is only available if federation sending has been
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disabled on the main process.
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* The server will only time connections out that have sent a ``PING`` command.
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If a ping is sent then the connection will be closed if no further commands
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are receieved within 15s. Both the client and server protocol implementations
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will send an initial PING on connection and ensure at least one command every
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5s is sent (not necessarily ``PING``).
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* ``RDATA`` commands *usually* include a numeric token, however if the stream
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has multiple rows to replicate per token the server will send multiple
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``RDATA`` commands, with all but the last having a token of ``batch``. See
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the documentation on ``commands.RdataCommand`` for further details.
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Architecture
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------------
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The basic structure of the protocol is line based, where the initial word of
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each line specifies the command. The rest of the line is parsed based on the
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command. For example, the `RDATA` command is defined as::
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RDATA <stream_name> <token> <row_json>
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(Note that `<row_json>` may contains spaces, but cannot contain newlines.)
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Blank lines are ignored.
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Keep alives
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~~~~~~~~~~~
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Both sides are expected to send at least one command every 5s or so, and
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should send a ``PING`` command if necessary. If either side do not receive a
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command within e.g. 15s then the connection should be closed.
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Because the server may be connected to manually using e.g. netcat, the timeouts
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aren't enabled until an initial ``PING`` command is seen. Both the client and
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server implementations below send a ``PING`` command immediately on connection to
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ensure the timeouts are enabled.
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This ensures that both sides can quickly realize if the tcp connection has gone
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and handle the situation appropriately.
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Start up
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~~~~~~~~
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When a new connection is made, the server:
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* Sends a ``SERVER`` command, which includes the identity of the server, allowing
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the client to detect if its connected to the expected server
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* Sends a ``PING`` command as above, to enable the client to time out connections
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promptly.
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The client:
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* Sends a ``NAME`` command, allowing the server to associate a human friendly
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name with the connection. This is optional.
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* Sends a ``PING`` as above
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* For each stream the client wishes to subscribe to it sends a ``REPLICATE``
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with the stream_name and token it wants to subscribe from.
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* On receipt of a ``SERVER`` command, checks that the server name matches the
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expected server name.
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Error handling
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~~~~~~~~~~~~~~
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If either side detects an error it can send an ``ERROR`` command and close the
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connection.
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If the client side loses the connection to the server it should reconnect,
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following the steps above.
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Congestion
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~~~~~~~~~~
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If the server sends messages faster than the client can consume them the server
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will first buffer a (fairly large) number of commands and then disconnect the
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client. This ensures that we don't queue up an unbounded number of commands in
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memory and gives us a potential oppurtunity to squawk loudly. When/if the client
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recovers it can reconnect to the server and ask for missed messages.
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Reliability
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~~~~~~~~~~~
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In general the replication stream should be consisdered an unreliable transport
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since e.g. commands are not resent if the connection disappears.
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The exception to that are the replication streams, i.e. RDATA commands, since
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these include tokens which can be used to restart the stream on connection
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errors.
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The client should keep track of the token in the last RDATA command received
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for each stream so that on reconneciton it can start streaming from the correct
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place. Note: not all RDATA have valid tokens due to batching. See
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``RdataCommand`` for more details.
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Example
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~~~~~~~
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An example iteraction is shown below. Each line is prefixed with '>' or '<' to
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indicate which side is sending, these are *not* included on the wire::
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* connection established *
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> SERVER localhost:8823
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> PING 1490197665618
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< NAME synapse.app.appservice
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< PING 1490197665618
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< REPLICATE events 1
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< REPLICATE backfill 1
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< REPLICATE caches 1
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> POSITION events 1
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> POSITION backfill 1
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> POSITION caches 1
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> RDATA caches 2 ["get_user_by_id",["@01register-user:localhost:8823"],1490197670513]
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> RDATA events 14 ["$149019767112vOHxz:localhost:8823",
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"!AFDCvgApUmpdfVjIXm:localhost:8823","m.room.guest_access","",null]
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< PING 1490197675618
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> ERROR server stopping
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* connection closed by server *
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The ``POSITION`` command sent by the server is used to set the clients position
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without needing to send data with the ``RDATA`` command.
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An example of a batched set of ``RDATA`` is::
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> RDATA caches batch ["get_user_by_id",["@test:localhost:8823"],1490197670513]
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> RDATA caches batch ["get_user_by_id",["@test2:localhost:8823"],1490197670513]
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> RDATA caches batch ["get_user_by_id",["@test3:localhost:8823"],1490197670513]
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> RDATA caches 54 ["get_user_by_id",["@test4:localhost:8823"],1490197670513]
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In this case the client shouldn't advance their caches token until it sees the
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the last ``RDATA``.
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@ -12,3 +12,35 @@
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""This module implements the TCP replication protocol used by synapse to
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communicate between the master process and its workers (when they're enabled).
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The protocol is based on fire and forget, line based commands. An example flow
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would be (where '>' indicates master->worker and '<' worker->master flows)::
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> SERVER example.com
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< REPLICATE events 53
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> RDATA events 54 ["$foo1:bar.com", ...]
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> RDATA events 55 ["$foo4:bar.com", ...]
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The example shows the server accepting a new connection and sending its identity
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with the `SERVER` command, followed by the client asking to subscribe to the
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`events` stream from the token `53`. The server then periodically sends `RDATA`
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commands which have the format `RDATA <stream_name> <token> <row>`, where the
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format of `<row>` is defined by the individual streams.
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Error reporting happens by either the client or server sending an `ERROR`
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command, and usually the connection will be closed.
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Structure of the module:
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* client.py - the client classes used for workers to connect to master
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* command.py - the definitions of all the valid commands
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* protocol.py - contains bot the client and server protocol implementations,
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these should not be used directly
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* resource.py - the server classes that accepts and handle client connections
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* streams.py - the definitons of all the valid streams
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Further details can be found in docs/tcp_replication.rst
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"""
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341
synapse/replication/tcp/commands.py
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341
synapse/replication/tcp/commands.py
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# -*- coding: utf-8 -*-
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# Copyright 2017 Vector Creations Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Defines the various valid commands
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The VALID_SERVER_COMMANDS and VALID_CLIENT_COMMANDS define which commands are
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allowed to be sent by which side.
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"""
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import logging
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import ujson as json
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logger = logging.getLogger(__name__)
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class Command(object):
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"""The base command class.
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All subclasses must set the NAME variable which equates to the name of the
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command on the wire.
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A full command line on the wire is constructed from `NAME + " " + to_line()`
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The default implementation creates a command of form `<NAME> <data>`
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"""
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NAME = None
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def __init__(self, data):
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self.data = data
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@classmethod
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def from_line(cls, line):
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"""Deserialises a line from the wire into this command. `line` does not
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include the command.
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"""
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return cls(line)
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def to_line(self):
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"""Serialises the comamnd for the wire. Does not include the command
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prefix.
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"""
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return self.data
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class ServerCommand(Command):
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"""Sent by the server on new connection and includes the server_name.
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Format::
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SERVER <server_name>
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"""
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NAME = "SERVER"
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class RdataCommand(Command):
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"""Sent by server when a subscribed stream has an update.
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Format::
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RDATA <stream_name> <token> <row_json>
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The `<token>` may either be a numeric stream id OR "batch". The latter case
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is used to support sending multiple updates with the same stream ID. This
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is done by sending an RDATA for each row, with all but the last RDATA having
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a token of "batch" and the last having the final stream ID.
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The client should batch all incoming RDATA with a token of "batch" (per
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stream_name) until it sees an RDATA with a numeric stream ID.
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`<token>` of "batch" maps to the instance variable `token` being None.
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An example of a batched series of RDATA::
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RDATA presence batch ["@foo:example.com", "online", ...]
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RDATA presence batch ["@bar:example.com", "online", ...]
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RDATA presence 59 ["@baz:example.com", "online", ...]
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"""
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NAME = "RDATA"
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def __init__(self, stream_name, token, row):
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self.stream_name = stream_name
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self.token = token
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self.row = row
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@classmethod
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def from_line(cls, line):
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stream_name, token, row_json = line.split(" ", 2)
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return cls(
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stream_name,
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None if token == "batch" else int(token),
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json.loads(row_json)
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)
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def to_line(self):
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return " ".join((
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self.stream_name,
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str(self.token) if self.token is not None else "batch",
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json.dumps(self.row),
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))
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class PositionCommand(Command):
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"""Sent by the client to tell the client the stream postition without
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needing to send an RDATA.
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"""
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NAME = "POSITION"
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def __init__(self, stream_name, token):
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self.stream_name = stream_name
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self.token = token
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@classmethod
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def from_line(cls, line):
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stream_name, token = line.split(" ", 1)
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return cls(stream_name, int(token))
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def to_line(self):
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return " ".join((self.stream_name, str(self.token),))
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class ErrorCommand(Command):
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"""Sent by either side if there was an ERROR. The data is a string describing
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the error.
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"""
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NAME = "ERROR"
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class PingCommand(Command):
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"""Sent by either side as a keep alive. The data is arbitary (often timestamp)
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"""
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NAME = "PING"
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class NameCommand(Command):
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"""Sent by client to inform the server of the client's identity. The data
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is the name
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"""
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NAME = "NAME"
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class ReplicateCommand(Command):
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"""Sent by the client to subscribe to the stream.
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Format::
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REPLICATE <stream_name> <token>
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Where <token> may be either:
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* a numeric stream_id to stream updates from
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* "NOW" to stream all subsequent updates.
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The <stream_name> can be "ALL" to subscribe to all known streams, in which
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case the <token> must be set to "NOW", i.e.::
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REPLICATE ALL NOW
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"""
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NAME = "REPLICATE"
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def __init__(self, stream_name, token):
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self.stream_name = stream_name
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self.token = token
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@classmethod
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def from_line(cls, line):
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stream_name, token = line.split(" ", 1)
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if token in ("NOW", "now"):
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token = "NOW"
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else:
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token = int(token)
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return cls(stream_name, token)
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def to_line(self):
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return " ".join((self.stream_name, str(self.token),))
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class UserSyncCommand(Command):
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"""Sent by the client to inform the server that a user has started or
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stopped syncing. Used to calculate presence on the master.
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Format::
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USER_SYNC <user_id> <state>
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Where <state> is either "start" or "stop"
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"""
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NAME = "USER_SYNC"
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def __init__(self, user_id, is_syncing):
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self.user_id = user_id
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self.is_syncing = is_syncing
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@classmethod
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def from_line(cls, line):
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user_id, state = line.split(" ", 1)
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if state not in ("start", "end"):
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raise Exception("Invalid USER_SYNC state %r" % (state,))
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return cls(user_id, state == "start")
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def to_line(self):
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return " ".join((self.user_id, "start" if self.is_syncing else "end"))
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class FederationAckCommand(Command):
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"""Sent by the client when it has processed up to a given point in the
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federation stream. This allows the master to drop in-memory caches of the
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federation stream.
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This must only be sent from one worker (i.e. the one sending federation)
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Format::
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FEDERATION_ACK <token>
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"""
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NAME = "FEDERATION_ACK"
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def __init__(self, token):
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self.token = token
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@classmethod
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def from_line(cls, line):
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return cls(int(line))
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def to_line(self):
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return str(self.token)
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class SyncCommand(Command):
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"""Used for testing. The client protocol implementation allows waiting
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on a SYNC command with a specified data.
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"""
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NAME = "SYNC"
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class RemovePusherCommand(Command):
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"""Sent by the client to request the master remove the given pusher.
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Format::
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REMOVE_PUSHER <app_id> <push_key> <user_id>
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"""
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NAME = "REMOVE_PUSHER"
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def __init__(self, app_id, push_key, user_id):
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self.user_id = user_id
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self.app_id = app_id
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self.push_key = push_key
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@classmethod
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def from_line(cls, line):
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app_id, push_key, user_id = line.split(" ", 2)
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||||
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return cls(app_id, push_key, user_id)
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def to_line(self):
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return " ".join((self.app_id, self.push_key, self.user_id))
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class InvalidateCacheCommand(Command):
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"""Sent by the client to invalidate an upstream cache.
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THIS IS NOT RELIABLE, AND SHOULD *NOT* BE USED ACCEPT FOR THINGS THAT ARE
|
||||
NOT DISASTROUS IF WE DROP ON THE FLOOR.
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||||
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||||
Mainly used to invalidate destination retry timing caches.
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||||
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Format::
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INVALIDATE_CACHE <cache_func> <keys_json>
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Where <keys_json> is a json list.
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"""
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NAME = "INVALIDATE_CACHE"
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def __init__(self, cache_func, keys):
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self.cache_func = cache_func
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self.keys = keys
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||||
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||||
@classmethod
|
||||
def from_line(cls, line):
|
||||
cache_func, keys_json = line.split(" ", 1)
|
||||
|
||||
return cls(cache_func, json.loads(keys_json))
|
||||
|
||||
def to_line(self):
|
||||
return " ".join((self.cache_func, json.dumps(self.keys)))
|
||||
|
||||
|
||||
# Map of command name to command type.
|
||||
COMMAND_MAP = {
|
||||
cmd.NAME: cmd
|
||||
for cmd in (
|
||||
ServerCommand,
|
||||
RdataCommand,
|
||||
PositionCommand,
|
||||
ErrorCommand,
|
||||
PingCommand,
|
||||
NameCommand,
|
||||
ReplicateCommand,
|
||||
UserSyncCommand,
|
||||
FederationAckCommand,
|
||||
SyncCommand,
|
||||
RemovePusherCommand,
|
||||
InvalidateCacheCommand,
|
||||
)
|
||||
}
|
||||
|
||||
# The commands the server is allowed to send
|
||||
VALID_SERVER_COMMANDS = (
|
||||
ServerCommand.NAME,
|
||||
RdataCommand.NAME,
|
||||
PositionCommand.NAME,
|
||||
ErrorCommand.NAME,
|
||||
PingCommand.NAME,
|
||||
SyncCommand.NAME,
|
||||
)
|
||||
|
||||
# The commands the client is allowed to send
|
||||
VALID_CLIENT_COMMANDS = (
|
||||
NameCommand.NAME,
|
||||
ReplicateCommand.NAME,
|
||||
PingCommand.NAME,
|
||||
UserSyncCommand.NAME,
|
||||
FederationAckCommand.NAME,
|
||||
RemovePusherCommand.NAME,
|
||||
InvalidateCacheCommand.NAME,
|
||||
ErrorCommand.NAME,
|
||||
)
|
601
synapse/replication/tcp/protocol.py
Normal file
601
synapse/replication/tcp/protocol.py
Normal file
@ -0,0 +1,601 @@
|
||||
# -*- coding: utf-8 -*-
|
||||
# Copyright 2017 Vector Creations 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 contains the implementation of both the client and server
|
||||
protocols.
|
||||
|
||||
The basic structure of the protocol is line based, where the initial word of
|
||||
each line specifies the command. The rest of the line is parsed based on the
|
||||
command. For example, the `RDATA` command is defined as::
|
||||
|
||||
RDATA <stream_name> <token> <row_json>
|
||||
|
||||
(Note that `<row_json>` may contains spaces, but cannot contain newlines.)
|
||||
|
||||
Blank lines are ignored.
|
||||
|
||||
# Example
|
||||
|
||||
An example iteraction is shown below. Each line is prefixed with '>' or '<' to
|
||||
indicate which side is sending, these are *not* included on the wire::
|
||||
|
||||
* connection established *
|
||||
> SERVER localhost:8823
|
||||
> PING 1490197665618
|
||||
< NAME synapse.app.appservice
|
||||
< PING 1490197665618
|
||||
< REPLICATE events 1
|
||||
< REPLICATE backfill 1
|
||||
< REPLICATE caches 1
|
||||
> POSITION events 1
|
||||
> POSITION backfill 1
|
||||
> POSITION caches 1
|
||||
> RDATA caches 2 ["get_user_by_id",["@01register-user:localhost:8823"],1490197670513]
|
||||
> RDATA events 14 ["$149019767112vOHxz:localhost:8823",
|
||||
"!AFDCvgApUmpdfVjIXm:localhost:8823","m.room.guest_access","",null]
|
||||
< PING 1490197675618
|
||||
> ERROR server stopping
|
||||
* connection closed by server *
|
||||
"""
|
||||
|
||||
from twisted.internet import defer
|
||||
from twisted.protocols.basic import LineOnlyReceiver
|
||||
|
||||
from commands import (
|
||||
COMMAND_MAP, VALID_CLIENT_COMMANDS, VALID_SERVER_COMMANDS,
|
||||
ErrorCommand, ServerCommand, RdataCommand, PositionCommand, PingCommand,
|
||||
NameCommand, ReplicateCommand, UserSyncCommand, SyncCommand,
|
||||
)
|
||||
from streams import STREAMS_MAP
|
||||
|
||||
from synapse.util.stringutils import random_string
|
||||
|
||||
import logging
|
||||
import synapse.metrics
|
||||
import struct
|
||||
import fcntl
|
||||
|
||||
|
||||
metrics = synapse.metrics.get_metrics_for(__name__)
|
||||
|
||||
inbound_commands_counter = metrics.register_counter(
|
||||
"inbound_commands", labels=["command", "name", "conn_id"],
|
||||
)
|
||||
outbound_commands_counter = metrics.register_counter(
|
||||
"outbound_commands", labels=["command", "name", "conn_id"],
|
||||
)
|
||||
|
||||
|
||||
# A list of all connected protocols. This allows us to send metrics about the
|
||||
# connections.
|
||||
connected_connections = []
|
||||
|
||||
|
||||
logger = logging.getLogger(__name__)
|
||||
|
||||
|
||||
PING_TIME = 5000
|
||||
|
||||
|
||||
class ConnectionStates(object):
|
||||
CONNECTING = "connecting"
|
||||
ESTABLISHED = "established"
|
||||
PAUSED = "paused"
|
||||
CLOSED = "closed"
|
||||
|
||||
|
||||
class BaseReplicationStreamProtocol(LineOnlyReceiver):
|
||||
"""Base replication protocol shared between client and server.
|
||||
|
||||
Reads lines (ignoring blank ones) and parses them into command classes,
|
||||
asserting that they are valid for the given direction, i.e. server commands
|
||||
are only sent by the server.
|
||||
|
||||
On receiving a new command it calls `on_<COMMAND_NAME>` with the parsed
|
||||
command.
|
||||
|
||||
It also sends `PING` periodically, and correctly times out remote connections
|
||||
(if they send a `PING` command)
|
||||
"""
|
||||
delimiter = b'\n'
|
||||
|
||||
VALID_INBOUND_COMMANDS = [] # Valid commands we expect to receive
|
||||
VALID_OUTBOUND_COMMANDS = [] # Valid commans we can send
|
||||
|
||||
max_line_buffer = 10000
|
||||
|
||||
def __init__(self, clock):
|
||||
self.clock = clock
|
||||
|
||||
self.last_received_command = self.clock.time_msec()
|
||||
self.last_sent_command = 0
|
||||
self.time_we_closed = None # When we requested the connection be closed
|
||||
|
||||
self.received_ping = False # Have we reecived a ping from the other side
|
||||
|
||||
self.state = ConnectionStates.CONNECTING
|
||||
|
||||
self.name = "anon" # The name sent by a client.
|
||||
self.conn_id = random_string(5) # To dedupe in case of name clashes.
|
||||
|
||||
# List of pending commands to send once we've established the connection
|
||||
self.pending_commands = []
|
||||
|
||||
# The LoopingCall for sending pings.
|
||||
self._send_ping_loop = None
|
||||
|
||||
def connectionMade(self):
|
||||
logger.info("[%s] Connection established", self.id())
|
||||
|
||||
self.state = ConnectionStates.ESTABLISHED
|
||||
|
||||
connected_connections.append(self) # Register connection for metrics
|
||||
|
||||
self.transport.registerProducer(self, True) # For the *Producing callbacks
|
||||
|
||||
self._send_pending_commands()
|
||||
|
||||
# Starts sending pings
|
||||
self._send_ping_loop = self.clock.looping_call(self.send_ping, 5000)
|
||||
|
||||
# Always send the initial PING so that the other side knows that they
|
||||
# can time us out.
|
||||
self.send_command(PingCommand(self.clock.time_msec()))
|
||||
|
||||
def send_ping(self):
|
||||
"""Periodically sends a ping and checks if we should close the connection
|
||||
due to the other side timing out.
|
||||
"""
|
||||
now = self.clock.time_msec()
|
||||
|
||||
if self.time_we_closed:
|
||||
if now - self.time_we_closed > PING_TIME * 3:
|
||||
logger.info(
|
||||
"[%s] Failed to close connection gracefully, aborting", self.id()
|
||||
)
|
||||
self.transport.abortConnection()
|
||||
else:
|
||||
if now - self.last_sent_command >= PING_TIME:
|
||||
self.send_command(PingCommand(now))
|
||||
|
||||
if self.received_ping and now - self.last_received_command > PING_TIME * 3:
|
||||
logger.info(
|
||||
"[%s] Connection hasn't received command in %r ms. Closing.",
|
||||
self.id(), now - self.last_received_command
|
||||
)
|
||||
self.send_error("ping timeout")
|
||||
|
||||
def lineReceived(self, line):
|
||||
"""Called when we've received a line
|
||||
"""
|
||||
if line.strip() == "":
|
||||
# Ignore blank lines
|
||||
return
|
||||
|
||||
line = line.decode("utf-8")
|
||||
cmd_name, rest_of_line = line.split(" ", 1)
|
||||
|
||||
if cmd_name not in self.VALID_INBOUND_COMMANDS:
|
||||
logger.error("[%s] invalid command %s", self.id(), cmd_name)
|
||||
self.send_error("invalid command: %s", cmd_name)
|
||||
return
|
||||
|
||||
self.last_received_command = self.clock.time_msec()
|
||||
|
||||
inbound_commands_counter.inc(cmd_name, self.name, self.conn_id)
|
||||
|
||||
cmd_cls = COMMAND_MAP[cmd_name]
|
||||
try:
|
||||
cmd = cmd_cls.from_line(rest_of_line)
|
||||
except Exception as e:
|
||||
logger.exception(
|
||||
"[%s] failed to parse line %r: %r", self.id(), cmd_name, rest_of_line
|
||||
)
|
||||
self.send_error(
|
||||
"failed to parse line for %r: %r (%r):" % (cmd_name, e, rest_of_line)
|
||||
)
|
||||
return
|
||||
|
||||
# Now lets try and call on_<CMD_NAME> function
|
||||
try:
|
||||
getattr(self, "on_%s" % (cmd_name,))(cmd)
|
||||
except Exception:
|
||||
logger.exception("[%s] Failed to handle line: %r", self.id(), line)
|
||||
|
||||
def close(self):
|
||||
self.time_we_closed = self.clock.time_msec()
|
||||
self.transport.loseConnection()
|
||||
self.on_connection_closed()
|
||||
|
||||
def send_error(self, error_string, *args):
|
||||
"""Send an error to remote and close the connection.
|
||||
"""
|
||||
self.send_command(ErrorCommand(error_string % args))
|
||||
self.close()
|
||||
|
||||
def send_command(self, cmd, do_buffer=True):
|
||||
"""Send a command if connection has been established.
|
||||
|
||||
Args:
|
||||
cmd (Command)
|
||||
do_buffer (bool): Whether to buffer the message or always attempt
|
||||
to send the command. This is mostly used to send an error
|
||||
message if we're about to close the connection due our buffers
|
||||
becoming full.
|
||||
"""
|
||||
if self.state == ConnectionStates.CLOSED:
|
||||
logger.info("[%s] Not sending, connection closed", self.id())
|
||||
return
|
||||
|
||||
if do_buffer and self.state != ConnectionStates.ESTABLISHED:
|
||||
self._queue_command(cmd)
|
||||
return
|
||||
|
||||
outbound_commands_counter.inc(cmd.NAME, self.name, self.conn_id)
|
||||
|
||||
string = "%s %s" % (cmd.NAME, cmd.to_line(),)
|
||||
if "\n" in string:
|
||||
raise Exception("Unexpected newline in command: %r", string)
|
||||
|
||||
self.sendLine(string.encode("utf-8"))
|
||||
|
||||
self.last_sent_command = self.clock.time_msec()
|
||||
|
||||
def _queue_command(self, cmd):
|
||||
"""Queue the command until the connection is ready to write to again.
|
||||
"""
|
||||
logger.info("[%s] Queing as conn %r, cmd: %r", self.id(), self.state, cmd)
|
||||
self.pending_commands.append(cmd)
|
||||
|
||||
if len(self.pending_commands) > self.max_line_buffer:
|
||||
# The other side is failing to keep up and out buffers are becoming
|
||||
# full, so lets close the connection.
|
||||
# XXX: should we squawk more loudly?
|
||||
logger.error("[%s] Remote failed to keep up", self.id())
|
||||
self.send_command(ErrorCommand("Failed to keep up"), do_buffer=False)
|
||||
self.close()
|
||||
|
||||
def _send_pending_commands(self):
|
||||
"""Send any queued commandes
|
||||
"""
|
||||
pending = self.pending_commands
|
||||
self.pending_commands = []
|
||||
for cmd in pending:
|
||||
self.send_command(cmd)
|
||||
|
||||
def on_PING(self, line):
|
||||
self.received_ping = True
|
||||
|
||||
def on_ERROR(self, cmd):
|
||||
logger.error("[%s] Remote reported error: %r", self.id(), cmd.data)
|
||||
|
||||
def pauseProducing(self):
|
||||
"""This is called when both the kernel send buffer and the twisted
|
||||
tcp connection send buffers have become full.
|
||||
|
||||
We don't actually have any control over those sizes, so we buffer some
|
||||
commands ourselves before knifing the connection due to the remote
|
||||
failing to keep up.
|
||||
"""
|
||||
logger.info("[%s] Pause producing", self.id())
|
||||
self.state = ConnectionStates.PAUSED
|
||||
|
||||
def resumeProducing(self):
|
||||
"""The remote has caught up after we started buffering!
|
||||
"""
|
||||
logger.info("[%s] Resume producing", self.id())
|
||||
self.state = ConnectionStates.ESTABLISHED
|
||||
self._send_pending_commands()
|
||||
|
||||
def stopProducing(self):
|
||||
"""We're never going to send any more data (normally because either
|
||||
we or the remote has closed the connection)
|
||||
"""
|
||||
logger.info("[%s] Stop producing", self.id())
|
||||
self.on_connection_closed()
|
||||
|
||||
def connectionLost(self, reason):
|
||||
logger.info("[%s] Replication connection closed: %r", self.id(), reason)
|
||||
|
||||
try:
|
||||
# Remove us from list of connections to be monitored
|
||||
connected_connections.remove(self)
|
||||
except ValueError:
|
||||
pass
|
||||
|
||||
# Stop the looping call sending pings.
|
||||
if self._send_ping_loop and self._send_ping_loop.running:
|
||||
self._send_ping_loop.stop()
|
||||
|
||||
self.on_connection_closed()
|
||||
|
||||
def on_connection_closed(self):
|
||||
logger.info("[%s] Connection was closed", self.id())
|
||||
|
||||
self.state = ConnectionStates.CLOSED
|
||||
self.pending_commands = []
|
||||
|
||||
if self.transport:
|
||||
self.transport.unregisterProducer()
|
||||
|
||||
def __str__(self):
|
||||
return "ReplicationConnection<name=%s,conn_id=%s,addr=%s>" % (
|
||||
self.name, self.conn_id, self.addr,
|
||||
)
|
||||
|
||||
def id(self):
|
||||
return "%s-%s" % (self.name, self.conn_id)
|
||||
|
||||
|
||||
class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
|
||||
VALID_INBOUND_COMMANDS = VALID_CLIENT_COMMANDS
|
||||
VALID_OUTBOUND_COMMANDS = VALID_SERVER_COMMANDS
|
||||
|
||||
def __init__(self, server_name, clock, streamer, addr):
|
||||
BaseReplicationStreamProtocol.__init__(self, clock) # Old style class
|
||||
|
||||
self.server_name = server_name
|
||||
self.streamer = streamer
|
||||
self.addr = addr
|
||||
|
||||
# The streams the client has subscribed to and is up to date with
|
||||
self.replication_streams = set()
|
||||
|
||||
# The streams the client is currently subscribing to.
|
||||
self.connecting_streams = set()
|
||||
|
||||
# Map from stream name to list of updates to send once we've finished
|
||||
# subscribing the client to the stream.
|
||||
self.pending_rdata = {}
|
||||
|
||||
def connectionMade(self):
|
||||
self.send_command(ServerCommand(self.server_name))
|
||||
BaseReplicationStreamProtocol.connectionMade(self)
|
||||
self.streamer.new_connection(self)
|
||||
|
||||
def on_NAME(self, cmd):
|
||||
self.name = cmd.data
|
||||
|
||||
def on_USER_SYNC(self, cmd):
|
||||
self.streamer.on_user_sync(self.conn_id, cmd.user_id, cmd.is_syncing)
|
||||
|
||||
def on_REPLICATE(self, cmd):
|
||||
stream_name = cmd.stream_name
|
||||
token = cmd.token
|
||||
|
||||
if stream_name == "ALL":
|
||||
# Subscribe to all streams we're publishing to.
|
||||
for stream in self.streamer.streams_by_name.iterkeys():
|
||||
self.subscribe_to_stream(stream, token)
|
||||
else:
|
||||
self.subscribe_to_stream(stream_name, token)
|
||||
|
||||
def on_FEDERATION_ACK(self, cmd):
|
||||
self.streamer.federation_ack(cmd.token)
|
||||
|
||||
def on_REMOVE_PUSHER(self, cmd):
|
||||
self.streamer.on_remove_pusher(cmd.app_id, cmd.push_key, cmd.user_id)
|
||||
|
||||
def onINVALIDATE_CACHE(self, cmd):
|
||||
self.streamer.on_invalidate_cache(cmd.cache_func, cmd.keys)
|
||||
|
||||
@defer.inlineCallbacks
|
||||
def subscribe_to_stream(self, stream_name, token):
|
||||
"""Subscribe the remote to a streams.
|
||||
|
||||
This invloves checking if they've missed anything and sending those
|
||||
updates down if they have. During that time new updates for the stream
|
||||
are queued and sent once we've sent down any missed updates.
|
||||
"""
|
||||
self.replication_streams.discard(stream_name)
|
||||
self.connecting_streams.add(stream_name)
|
||||
|
||||
try:
|
||||
# Get missing updates
|
||||
updates, current_token = yield self.streamer.get_stream_updates(
|
||||
stream_name, token,
|
||||
)
|
||||
|
||||
# Send all the missing updates
|
||||
for update in updates:
|
||||
token, row = update[0], update[1]
|
||||
self.send_command(RdataCommand(stream_name, token, row))
|
||||
|
||||
# Now we can send any updates that came in while we were subscribing
|
||||
pending_rdata = self.pending_rdata.pop(stream_name, [])
|
||||
for token, update in pending_rdata:
|
||||
self.send_command(RdataCommand(stream_name, token, update))
|
||||
|
||||
# We send a POSITION command to ensure that they have an up to
|
||||
# date token (especially useful if we didn't send any updates
|
||||
# above)
|
||||
self.send_command(PositionCommand(stream_name, current_token))
|
||||
|
||||
# They're now fully subscribed
|
||||
self.replication_streams.add(stream_name)
|
||||
except Exception as e:
|
||||
logger.exception("[%s] Failed to handle REPLICATE command", self.id())
|
||||
self.send_error("failed to handle replicate: %r", e)
|
||||
finally:
|
||||
self.connecting_streams.discard(stream_name)
|
||||
|
||||
def stream_update(self, stream_name, token, data):
|
||||
"""Called when a new update is available to stream to clients.
|
||||
|
||||
We need to check if the client is interested in the stream or not
|
||||
"""
|
||||
if stream_name in self.replication_streams:
|
||||
# The client is subscribed to the stream
|
||||
self.send_command(RdataCommand(stream_name, token, data))
|
||||
elif stream_name in self.connecting_streams:
|
||||
# The client is being subscribed to the stream
|
||||
logger.info("[%s] Queuing RDATA %r %r", self.id(), stream_name, token)
|
||||
self.pending_rdata.setdefault(stream_name, []).append((token, data))
|
||||
else:
|
||||
# The client isn't subscribed
|
||||
logger.debug("[%s] Dropping RDATA %r %r", self.id(), stream_name, token)
|
||||
|
||||
def send_sync(self, data):
|
||||
self.send_command(SyncCommand(data))
|
||||
|
||||
def on_connection_closed(self):
|
||||
BaseReplicationStreamProtocol.on_connection_closed(self)
|
||||
logger.info("[%s] Replication connection closed", self.id())
|
||||
self.streamer.lost_connection(self)
|
||||
|
||||
|
||||
class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
|
||||
VALID_INBOUND_COMMANDS = VALID_SERVER_COMMANDS
|
||||
VALID_OUTBOUND_COMMANDS = VALID_CLIENT_COMMANDS
|
||||
|
||||
def __init__(self, client_name, server_name, clock, handler):
|
||||
BaseReplicationStreamProtocol.__init__(self, clock)
|
||||
|
||||
self.client_name = client_name
|
||||
self.server_name = server_name
|
||||
self.handler = handler
|
||||
|
||||
# Map of stream to batched updates. See RdataCommand for info on how
|
||||
# batching works.
|
||||
self.pending_batches = {}
|
||||
|
||||
def connectionMade(self):
|
||||
self.send_command(NameCommand(self.client_name))
|
||||
BaseReplicationStreamProtocol.connectionMade(self)
|
||||
|
||||
# Once we've connected subscribe to the necessary streams
|
||||
for stream_name, token in self.handler.get_streams_to_replicate().iteritems():
|
||||
self.replicate(stream_name, token)
|
||||
|
||||
# Tell the server if we have any users currently syncing (should only
|
||||
# happen on synchrotrons)
|
||||
currently_syncing = self.handler.get_currently_syncing_users()
|
||||
for user_id in currently_syncing:
|
||||
self.send_command(UserSyncCommand(user_id, True))
|
||||
|
||||
# We've now finished connecting to so inform the client handler
|
||||
self.handler.update_connection(self)
|
||||
|
||||
def on_SERVER(self, cmd):
|
||||
if cmd.data != self.server_name:
|
||||
logger.error("[%s] Connected to wrong remote: %r", self.id(), cmd.data)
|
||||
self.transport.abortConnection()
|
||||
|
||||
def on_RDATA(self, cmd):
|
||||
try:
|
||||
row = STREAMS_MAP[cmd.stream_name].ROW_TYPE(*cmd.row)
|
||||
except Exception:
|
||||
logger.exception(
|
||||
"[%s] Failed to parse RDATA: %r %r",
|
||||
self.id(), cmd.stream_name, cmd.row
|
||||
)
|
||||
raise
|
||||
|
||||
if cmd.token is None:
|
||||
# I.e. this is part of a batch of updates for this stream. Batch
|
||||
# until we get an update for the stream with a non None token
|
||||
self.pending_batches.setdefault(cmd.stream_name, []).append(row)
|
||||
else:
|
||||
# Check if this is the last of a batch of updates
|
||||
rows = self.pending_batches.pop(cmd.stream_name, [])
|
||||
rows.append(row)
|
||||
|
||||
self.handler.on_rdata(cmd.stream_name, cmd.token, rows)
|
||||
|
||||
def on_POSITION(self, cmd):
|
||||
self.handler.on_position(cmd.stream_name, cmd.token)
|
||||
|
||||
def on_SYNC(self, cmd):
|
||||
self.handler.on_sync(cmd.data)
|
||||
|
||||
def replicate(self, stream_name, token):
|
||||
"""Send the subscription request to the server
|
||||
"""
|
||||
if stream_name not in STREAMS_MAP:
|
||||
raise Exception("Invalid stream name %r" % (stream_name,))
|
||||
|
||||
logger.info(
|
||||
"[%s] Subscribing to replication stream: %r from %r",
|
||||
self.id(), stream_name, token
|
||||
)
|
||||
|
||||
self.send_command(ReplicateCommand(stream_name, token))
|
||||
|
||||
def on_connection_closed(self):
|
||||
BaseReplicationStreamProtocol.on_connection_closed(self)
|
||||
self.handler.update_connection(None)
|
||||
|
||||
|
||||
# The following simply registers metrics for the replication connections
|
||||
|
||||
metrics.register_callback(
|
||||
"pending_commands",
|
||||
lambda: {
|
||||
(p.name, p.conn_id): len(p.pending_commands)
|
||||
for p in connected_connections
|
||||
},
|
||||
labels=["name", "conn_id"],
|
||||
)
|
||||
|
||||
|
||||
def transport_buffer_size(protocol):
|
||||
if protocol.transport:
|
||||
size = len(protocol.transport.dataBuffer) + protocol.transport._tempDataLen
|
||||
return size
|
||||
return 0
|
||||
|
||||
|
||||
metrics.register_callback(
|
||||
"transport_send_buffer",
|
||||
lambda: {
|
||||
(p.name, p.conn_id): transport_buffer_size(p)
|
||||
for p in connected_connections
|
||||
},
|
||||
labels=["name", "conn_id"],
|
||||
)
|
||||
|
||||
|
||||
def transport_kernel_read_buffer_size(protocol, read=True):
|
||||
SIOCINQ = 0x541B
|
||||
SIOCOUTQ = 0x5411
|
||||
|
||||
if protocol.transport:
|
||||
fileno = protocol.transport.getHandle().fileno()
|
||||
if read:
|
||||
op = SIOCINQ
|
||||
else:
|
||||
op = SIOCOUTQ
|
||||
size = struct.unpack("I", fcntl.ioctl(fileno, op, '\0\0\0\0'))[0]
|
||||
return size
|
||||
return 0
|
||||
|
||||
|
||||
metrics.register_callback(
|
||||
"transport_kernel_send_buffer",
|
||||
lambda: {
|
||||
(p.name, p.conn_id): transport_kernel_read_buffer_size(p, False)
|
||||
for p in connected_connections
|
||||
},
|
||||
labels=["name", "conn_id"],
|
||||
)
|
||||
|
||||
|
||||
metrics.register_callback(
|
||||
"transport_kernel_read_buffer",
|
||||
lambda: {
|
||||
(p.name, p.conn_id): transport_kernel_read_buffer_size(p, True)
|
||||
for p in connected_connections
|
||||
},
|
||||
labels=["name", "conn_id"],
|
||||
)
|
Loading…
Reference in New Issue
Block a user