Remove unused 'stream' param of REPLICATE and update docs

docs/tcp_replication.md

@@ -14,16 +14,16 @@ example flow would be (where '>' indicates master to worker and
 '<' worker to master flows):
 
     > SERVER example.com
-    < REPLICATE events 53
+    < REPLICATE
+    > POSITION 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.
+The example shows the server accepting a new connection and sending its identity
+with the `SERVER` command, followed by the client server to respond with the
+position of all streams. 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.
@@ -32,9 +32,6 @@ Since the protocol is a simple line based, its possible to manually
 connect to the server using a tool like netcat. A few things should be
 noted when manually using the protocol:
 
--   When subscribing to a stream using `REPLICATE`, the special token
-    `NOW` can be used to get all future updates. The special stream name
-    `ALL` can be used with `NOW` to subscribe to all available streams.
 -   The federation stream is only available if federation sending has
     been disabled on the main process.
 -   The server will only time connections out that have sent a `PING`
@@ -91,9 +88,7 @@ The client:
 -   Sends a `NAME` command, allowing the server to associate a human
     friendly name with the connection. This is optional.
 -   Sends a `PING` as above
--   For each stream the client wishes to subscribe to it sends a
-    `REPLICATE` with the `stream_name` and token it wants to subscribe
-    from.
+-   Sends a `REPLICATE` to get the current position of all streams.
 -   On receipt of a `SERVER` command, checks that the server name
     matches the expected server name.
 
@@ -140,9 +135,7 @@ the wire:
     > PING 1490197665618
     < NAME synapse.app.appservice
     < PING 1490197665618
-    < REPLICATE events 1
-    < REPLICATE backfill 1
-    < REPLICATE caches 1
+    < REPLICATE
     > POSITION events 1
     > POSITION backfill 1
     > POSITION caches 1
@@ -199,20 +192,7 @@ client (C):
 
 #### REPLICATE (C)
 
-Asks the server to replicate a given stream. The syntax is:
-
-```
-    REPLICATE <stream_name> <token>
-```
-
-Where `<token>` may be either:
- * a numeric stream_id to stream updates since (exclusive)
- * `NOW` to stream all subsequent updates.
-
-The `<stream_name>` is the name of a replication stream to subscribe
-to (see [here](../synapse/replication/tcp/streams/_base.py) for a list
-of streams). It can also be `ALL` to subscribe to all known streams,
-in which case the `<token>` must be set to `NOW`.
+Asks the server for the current position of all streams.
 
 #### USER_SYNC (C)
 

synapse/replication/tcp/commands.py

@@ -179,29 +179,24 @@ class NameCommand(Command):
 
 
 class ReplicateCommand(Command):
-    """Sent by the client to subscribe to the stream.
+    """Sent by the client to subscribe to streams.
 
     Format::
 
-        REPLICATE <stream_name>
-
-    The <stream_name> can be "ALL" to subscribe to all known streams
+        REPLICATE
     """
 
     NAME = "REPLICATE"
 
-    def __init__(self, stream_name):
-        self.stream_name = stream_name
+    def __init__(self):
+        pass
 
     @classmethod
     def from_line(cls, line):
-        return cls(line)
+        return cls()
 
     def to_line(self):
-        return self.stream_name
-
-    def get_logcontext_id(self):
-        return "REPLICATE-" + self.stream_name
+        return ""
 
 
 class UserSyncCommand(Command):

synapse/replication/tcp/protocol.py

@@ -35,9 +35,7 @@ indicate which side is sending, these are *not* included on the wire::
     > PING 1490197665618
     < NAME synapse.app.appservice
     < PING 1490197665618
-    < REPLICATE events 1
-    < REPLICATE backfill 1
-    < REPLICATE caches 1
+    < REPLICATE
     > POSITION events 1
     > POSITION backfill 1
     > POSITION caches 1
@@ -662,7 +660,7 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
         """
         logger.info("[%s] Subscribing to replication streams", self.id())
 
-        self.send_command(ReplicateCommand("ALL"))
+        self.send_command(ReplicateCommand())
 
     def on_connection_closed(self):
         BaseReplicationStreamProtocol.on_connection_closed(self)

tests/replication/tcp/streams/_base.py

@@ -69,9 +69,9 @@ class BaseStreamTestCase(unittest.HomeserverTestCase):
         self.streamer.on_notifier_poke()
         self.pump(0.1)
 
-    def replicate_stream(self, stream, token="NOW"):
+    def replicate_stream(self):
         """Make the client end a REPLICATE command to set up a subscription to a stream"""
-        self.client.send_command(ReplicateCommand(stream))
+        self.client.send_command(ReplicateCommand())
 
 
 class TestReplicationClientHandler(object):

tests/replication/tcp/streams/test_receipts.py

@@ -24,7 +24,7 @@ class ReceiptsStreamTestCase(BaseStreamTestCase):
         self.reconnect()
 
         # make the client subscribe to the receipts stream
-        self.replicate_stream("receipts", "NOW")
+        self.replicate_stream()
         self.test_handler.streams.add("receipts")
 
         # tell the master to send a new receipt