Fix federation in demo scripts. (#12783)

changelog.d/12783.misc

@@ -0,0 +1 @@
+Fix federation when using the demo scripts.

demo/start.sh

@@ -12,17 +12,20 @@ export PYTHONPATH
 
 echo "$PYTHONPATH"
 
+# Create servers which listen on HTTP at 808x and HTTPS at 848x.
 for port in 8080 8081 8082; do
     echo "Starting server on port $port... "
 
     https_port=$((port + 400))
     mkdir -p demo/$port
     pushd demo/$port || exit
 
-    # Generate the configuration for the homeserver at localhost:848x.
+    # Generate the configuration for the homeserver at localhost:848x, note that
+    # the homeserver name needs to match the HTTPS listening port for federation
+    # to properly work..
     python3 -m synapse.app.homeserver \
         --generate-config \
-        --server-name "localhost:$port" \
+        --server-name "localhost:$https_port" \
         --config-path "$port.config" \
         --report-stats no
 

docs/development/demo.md

@@ -5,7 +5,7 @@
 Requires you to have a [Synapse development environment setup](https://matrix-org.github.io/synapse/develop/development/contributing_guide.html#4-install-the-dependencies).
 
 The demo setup allows running three federation Synapse servers, with server
-names `localhost:8080`, `localhost:8081`, and `localhost:8082`.
+names `localhost:8480`, `localhost:8481`, and `localhost:8482`.
 
 You can access them via any Matrix client over HTTP at `localhost:8080`,
 `localhost:8081`, and `localhost:8082` or over HTTPS at `localhost:8480`,
@@ -20,9 +20,10 @@ and the servers are configured in a highly insecure way, including:
 The servers are configured to store their data under `demo/8080`, `demo/8081`, and
 `demo/8082`. This includes configuration, logs, SQLite databases, and media.
 
-Note that when joining a public room on a different HS via "#foo:bar.net", then
-you are (in the current impl) joining a room with room_id "foo". This means that
-it won't work if your HS already has a room with that name.
+Note that when joining a public room on a different homeserver via "#foo:bar.net",
+then you are (in the current implementation) joining a room with room_id "foo".
+This means that it won't work if your homeserver already has a room with that
+name.
 
 ## Using the demo scripts