Remove `worker_replication_*` settings (#15491)

* Add master to the instance_map as part of Complement, have ReplicationEndpoint look at instance_map for master.

* Fix typo in drive by.

* Remove unnecessary worker_replication_* bits from unit tests and add master to instance_map(hopefully in the right place)

* Several updates:

1. Switch from master to main for naming the main process in the instance_map. Add useful constants for easier adjustment of names in the future.
2. Add backwards compatibility for worker_replication_* to allow time to transition to new style. Make sure to prioritize declaring main directly on the instance_map.
3. Clean up old comments/commented out code.
4. Adjust unit tests to match with new code.
5. Adjust Complement setup infrastructure to only add main to the instance_map if workers are used and remove now unused options from the worker.yaml template.

* Initial Docs upload

* Changelog

* Missed some commented out code that can go now

* Remove TODO comment that no longer holds true.

* Fix links in docs

* More docs

* Remove debug logging

* Apply suggestions from code review

Co-authored-by: reivilibre <olivier@librepush.net>

* Apply suggestions from code review

Co-authored-by: reivilibre <olivier@librepush.net>

* Update version to latest, include completeish before/after examples in upgrade notes.

* Fix up and docs too

---------

Co-authored-by: reivilibre <olivier@librepush.net>

1 files changed, 78 insertions, 0 deletions

diff --git a/docs/upgrade.md b/docs/upgrade.md

index 0886b03115..0625de8afb 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -88,6 +88,84 @@ process, for example:
     dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     ```
 
+# Upgrading to v1.84.0
+
+## Deprecation of `worker_replication_*` configuration settings
+
+When using workers, 
+* `worker_replication_host`
+* `worker_replication_http_port`
+* `worker_replication_http_tls`
+ 
+can now be removed from individual worker YAML configuration ***if*** you add the main process to the `instance_map` in the shared YAML configuration,
+using the name `main`.
+
+### Before:
+Shared YAML
+```yaml
+instance_map:
+  generic_worker1:
+    host: localhost
+    port: 5678
+    tls: false
+```
+Worker YAML
+```yaml
+worker_app: synapse.app.generic_worker
+worker_name: generic_worker1
+
+worker_replication_host: localhost
+worker_replication_http_port: 3456
+worker_replication_http_tls: false
+
+worker_listeners:
+  - type: http
+    port: 1234
+    resources:
+      - names: [client, federation]
+  - type: http
+    port: 5678
+    resources:
+      - names: [replication]
+
+worker_log_config: /etc/matrix-synapse/generic-worker-log.yaml
+```
+### After:
+Shared YAML
+```yaml
+instance_map:
+  main:
+    host: localhost
+    port: 3456
+    tls: false
+  generic_worker1:
+    host: localhost
+    port: 5678
+    tls: false
+```
+Worker YAML
+```yaml
+worker_app: synapse.app.generic_worker
+worker_name: generic_worker1
+
+worker_listeners:
+  - type: http
+    port: 1234
+    resources:
+      - names: [client, federation]
+  - type: http
+    port: 5678
+    resources:
+      - names: [replication]
+
+worker_log_config: /etc/matrix-synapse/generic-worker-log.yaml
+
+```
+Notes: 
+* `tls` is optional but mirrors the functionality of `worker_replication_http_tls`
+
+
+
 # Upgrading to v1.81.0
 
 ## Application service path & authentication deprecations