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Fix up docs

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Erik Johnston 2017-03-31 11:19:24 +01:00
parent 63fcc42990
commit bfcf016714
4 changed files with 12 additions and 28 deletions
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16
docs/tcp_replication.rst
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@ -1,20 +1,20 @@
TCP Replication
===============
This describes the TCP replication protocol that replaces the HTTP protocol.
Motivation
----------
The HTTP API used long poll from the workers to the master, this has the problem
of causing a lot of duplicate work on the server. This TCP protocol aims to
solve.
Previously the workers used an HTTP long poll mechanism to get updates from the
master, which had the problem of causing a lot of duplicate work on the server.
This TCP protocol replaces those APIs with the aim of increased efficiency.
Overview
--------
The protocol is based on fire and forget, line based commands. An example flow
would be (where '>' indicates master->worker and '<' worker->master flows)::
would be (where '>' indicates master to worker and '<' worker to master flows)::
> SERVER example.com
< REPLICATE events 53
@ -24,7 +24,7 @@ would be (where '>' indicates master->worker and '<' worker->master flows)::
The example shows the server accepting a new connection and sending its identity
with the ``SERVER`` command, followed by the client asking to subscribe to the
``events`` stream from the token ``53``. The server then periodically sends ``RDATA``
commands which have the format ``RDATA <stream_name> <token> <row>```, where the
commands which have the format ``RDATA <stream_name> <token> <row>``, where the
format of ``<row>`` is defined by the individual streams.
Error reporting happens by either the client or server sending an `ERROR`
@ -125,7 +125,7 @@ recovers it can reconnect to the server and ask for missed messages.
Reliability
~~~~~~~~~~~
In general the replication stream should be consisdered an unreliable transport
In general the replication stream should be considered an unreliable transport
since e.g. commands are not resent if the connection disappears.
The exception to that are the replication streams, i.e. RDATA commands, since

18
synapse/replication/tcp/__init__.py
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@ -16,22 +16,7 @@
"""This module implements the TCP replication protocol used by synapse to
communicate between the master process and its workers (when they're enabled).
The protocol is based on fire and forget, line based commands. An example flow
would be (where '>' indicates master->worker and '<' worker->master flows)::
> SERVER example.com
< REPLICATE events 53
> RDATA events 54 ["$foo1:bar.com", ...]
> RDATA events 55 ["$foo4:bar.com", ...]
The example shows the server accepting a new connection and sending its identity
with the `SERVER` command, followed by the client asking to subscribe to the
`events` stream from the token `53`. The server then periodically sends `RDATA`
commands which have the format `RDATA <stream_name> <token> <row>`, where the
format of `<row>` is defined by the individual streams.
Error reporting happens by either the client or server sending an `ERROR`
command, and usually the connection will be closed.
Further details can be found in docs/tcp_replication.rst
Structure of the module:
@ -42,5 +27,4 @@ Structure of the module:
* resource.py - the server classes that accepts and handle client connections
* streams.py - the definitons of all the valid streams
Further details can be found in docs/tcp_replication.rst
"""

4
synapse/replication/tcp/streams.py
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@ -154,8 +154,8 @@ class Stream(object):
True then limit is provided, otherwise it's not.
Returns:
list(tuple): the first entry in the tuple is the token for that
update, and the rest of the tuple gets used to construct
Deferred(list(tuple)): the first entry in the tuple is the token for
that update, and the rest of the tuple gets used to construct
a ``ROW_TYPE`` instance
"""
raise NotImplementedError()

2
synapse/storage/pusher.py
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@ -139,7 +139,7 @@ class PusherStore(SQLBaseStore):
"""Get all the pushers that have changed between the given tokens.
Returns:
list(tuple): each tuple consists of:
Deferred(list(tuple)): each tuple consists of:
stream_id (str)
user_id (str)
app_id (str)