Add documentation for missing worker types. (#11599)

And clean-up the endpoints which should be routed to workers.

2 files changed, 77 insertions, 14 deletions

diff --git a/changelog.d/11599.doc b/changelog.d/11599.doc
new file mode 100644
index 0000000000..f07cfbef4e
--- /dev/null
+++ b/changelog.d/11599.doc
@@ -0,0 +1 @@
+Document support for the `to_device`, `account_data`, `receipts`, and `presence` stream writers for workers.
diff --git a/docs/workers.md b/docs/workers.md
index dadde4d726..b82a6900ac 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -178,8 +178,11 @@ recommend the use of `systemd` where available: for information on setting up
 
 ### `synapse.app.generic_worker`
 
-This worker can handle API requests matching the following regular
-expressions:
+This worker can handle API requests matching the following regular expressions.
+These endpoints can be routed to any worker. If a worker is set up to handle a
+stream then, for maximum efficiency, additional endpoints should be routed to that
+worker: refer to the [stream writers](#stream-writers) section below for further
+information.
 
     # Sync requests
     ^/_matrix/client/(v2_alpha|r0|v3)/sync$
@@ -225,19 +228,23 @@ expressions:
     ^/_matrix/client/unstable/org.matrix.msc2946/rooms/.*/spaces$
     ^/_matrix/client/(v1|unstable/org.matrix.msc2946)/rooms/.*/hierarchy$
     ^/_matrix/client/unstable/im.nheko.summary/rooms/.*/summary$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/account/3pid$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/devices$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/keys/query$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/keys/changes$
+    ^/_matrix/client/(r0|v3|unstable)/account/3pid$
+    ^/_matrix/client/(r0|v3|unstable)/devices$
     ^/_matrix/client/versions$
     ^/_matrix/client/(api/v1|r0|v3|unstable)/voip/turnServer$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/joined_groups$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/publicised_groups$
-    ^/_matrix/client/(api/v1|r0|v3|unstable)/publicised_groups/
+    ^/_matrix/client/(r0|v3|unstable)/joined_groups$
+    ^/_matrix/client/(r0|v3|unstable)/publicised_groups$
+    ^/_matrix/client/(r0|v3|unstable)/publicised_groups/
     ^/_matrix/client/(api/v1|r0|v3|unstable)/rooms/.*/event/
     ^/_matrix/client/(api/v1|r0|v3|unstable)/joined_rooms$
     ^/_matrix/client/(api/v1|r0|v3|unstable)/search$
 
+    # Encryption requests
+    ^/_matrix/client/(r0|v3|unstable)/keys/query$
+    ^/_matrix/client/(r0|v3|unstable)/keys/changes$
+    ^/_matrix/client/(r0|v3|unstable)/keys/claim$
+    ^/_matrix/client/(r0|v3|unstable)/room_keys/
+
     # Registration/login requests
     ^/_matrix/client/(api/v1|r0|v3|unstable)/login$
     ^/_matrix/client/(r0|v3|unstable)/register$
@@ -251,6 +258,20 @@ expressions:
     ^/_matrix/client/(api/v1|r0|v3|unstable)/join/
     ^/_matrix/client/(api/v1|r0|v3|unstable)/profile/
 
+    # Device requests
+    ^/_matrix/client/(r0|v3|unstable)/sendToDevice/
+
+    # Account data requests
+    ^/_matrix/client/(r0|v3|unstable)/.*/tags
+    ^/_matrix/client/(r0|v3|unstable)/.*/account_data
+
+    # Receipts requests
+    ^/_matrix/client/(r0|v3|unstable)/rooms/.*/receipt
+    ^/_matrix/client/(r0|v3|unstable)/rooms/.*/read_markers
+
+    # Presence requests
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/presence/
+
 
 Additionally, the following REST endpoints can be handled for GET requests:
 
@@ -330,12 +351,10 @@ Additionally, there is *experimental* support for moving writing of specific
 streams (such as events) off of the main process to a particular worker. (This
 is only supported with Redis-based replication.)
 
-Currently supported streams are `events` and `typing`.
-
 To enable this, the worker must have a HTTP replication listener configured,
-have a `worker_name` and be listed in the `instance_map` config. For example to
-move event persistence off to a dedicated worker, the shared configuration would
-include:
+have a `worker_name` and be listed in the `instance_map` config. The same worker
+can handle multiple streams. For example, to move event persistence off to a
+dedicated worker, the shared configuration would include:
 
 ```yaml
 instance_map:
@@ -347,6 +366,12 @@ stream_writers:
     events: event_persister1
 ```
 
+Some of the streams have associated endpoints which, for maximum efficiency, should
+be routed to the workers handling that stream. See below for the currently supported
+streams and the endpoints associated with them:
+
+##### The `events` stream
+
 The `events` stream also experimentally supports having multiple writers, where
 work is sharded between them by room ID. Note that you *must* restart all worker
 instances when adding or removing event persisters. An example `stream_writers`
@@ -359,6 +384,43 @@ stream_writers:
         - event_persister2
 ```
 
+##### The `typing` stream
+
+The following endpoints should be routed directly to the workers configured as
+stream writers for the `typing` stream:
+
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/rooms/.*/typing
+
+##### The `to_device` stream
+
+The following endpoints should be routed directly to the workers configured as
+stream writers for the `to_device` stream:
+
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/sendToDevice/
+
+##### The `account_data` stream
+
+The following endpoints should be routed directly to the workers configured as
+stream writers for the `account_data` stream:
+
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/.*/tags
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/.*/account_data
+
+##### The `receipts` stream
+
+The following endpoints should be routed directly to the workers configured as
+stream writers for the `receipts` stream:
+
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/rooms/.*/receipt
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/rooms/.*/read_markers
+
+##### The `presence` stream
+
+The following endpoints should be routed directly to the workers configured as
+stream writers for the `presence` stream:
+
+    ^/_matrix/client/(api/v1|r0|v3|unstable)/presence/
+
 #### Background tasks
 
 There is also *experimental* support for moving background tasks to a separate