Add missing worker settings to shared configuration (#14748)

* Add missing worker settings to shared configuration

* newsfile

* update docs after review

* more update for doc

* This -> These

Co-authored-by: David Robertson <david.m.robertson1@gmail.com>

3 files changed, 85 insertions, 11 deletions

diff --git a/changelog.d/14748.doc b/changelog.d/14748.doc
new file mode 100644
index 0000000000..6926136f79
--- /dev/null
+++ b/changelog.d/14748.doc
@@ -0,0 +1 @@
+Add missing worker settings to shared configuration documentation.
\ No newline at end of file
diff --git a/docs/usage/configuration/config_documentation.md b/docs/usage/configuration/config_documentation.md
index 6cfcce817f..93d6c7fb02 100644
--- a/docs/usage/configuration/config_documentation.md
+++ b/docs/usage/configuration/config_documentation.md
@@ -2623,18 +2623,18 @@ state events are shared with users:
 - `m.room.topic`
 
 To change the default behavior, use the following sub-options:
-* `disable_default_event_types`: boolean. Set to `true` to disable the above 
+* `disable_default_event_types`: boolean. Set to `true` to disable the above
   defaults. If this is enabled, only the event types listed in
   `additional_event_types` are shared. Defaults to `false`.
-* `additional_event_types`: A list of additional state events to include in the 
-  events to be shared. By default, this list is empty (so only the default event 
+* `additional_event_types`: A list of additional state events to include in the
+  events to be shared. By default, this list is empty (so only the default event
   types are shared).
 
   Each entry in this list should be either a single string or a list of two
-  strings. 
+  strings.
   * A standalone string `t` represents all events with type `t` (i.e.
     with no restrictions on state keys).
-  * A pair of strings `[t, s]` represents a single event with type `t` and 
+  * A pair of strings `[t, s]` represents a single event with type `t` and
     state key `s`. The same type can appear in two entries with different state
     keys: in this situation, both state keys are included in prejoin state.
 
@@ -3126,7 +3126,7 @@ Options for each entry include:
        * `picture_claim`: name of the claim containing an url for the user's profile picture.
          Defaults to 'picture', which OpenID Connect compliant providers should provide
          and has to refer to a direct image file such as PNG, JPEG, or GIF image file.
-         
+
          Currently only supported in monolithic (single-process) server configurations
          where the media repository runs within the Synapse process.
 
@@ -3865,6 +3865,48 @@ Example configuration:
 run_background_tasks_on: worker1
 ```
 ---
+### `update_user_directory_from_worker`
+
+The [worker](../../workers.md#updating-the-user-directory) that is used to
+update the user directory. If not provided this defaults to the main process.
+
+Example configuration:
+```yaml
+update_user_directory_from_worker: worker1
+```
+
+_Added in Synapse 1.59.0._
+
+---
+### `notify_appservices_from_worker`
+
+The [worker](../../workers.md#notifying-application-services) that is used to
+send output traffic to Application Services. If not provided this defaults
+to the main process.
+
+Example configuration:
+```yaml
+notify_appservices_from_worker: worker1
+```
+
+_Added in Synapse 1.59.0._
+
+---
+### `media_instance_running_background_jobs`
+
+The [worker](../../workers.md#synapseappmedia_repository) that is used to run
+background tasks for media repository. If running multiple media repositories
+you must configure a single instance to run the background tasks. If not provided
+this defaults to the main process or your single `media_repository` worker.
+
+Example configuration:
+```yaml
+media_instance_running_background_jobs: worker1
+```
+
+_Added in Synapse 1.16.0._
+
+---
 ### `redis`
 
 Configuration for Redis when using workers. This *must* be enabled when using workers.
diff --git a/docs/workers.md b/docs/workers.md
index c21638564e..bc66f0e1bc 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -465,7 +465,8 @@ An example for a dedicated background worker instance:
 
 You can designate one generic worker to update the user directory.
 
-Specify its name in the shared configuration as follows:
+Specify its name in the [shared configuration](usage/configuration/config_documentation.md#update_user_directory_from_worker)
+as follows:
 
 ```yaml
 update_user_directory_from_worker: worker_name
@@ -490,7 +491,8 @@ worker application type.
 
 You can designate one generic worker to send output traffic to Application Services.
 Doesn't handle any REST endpoints itself, but you should specify its name in the
-shared configuration as follows:
+[shared configuration](usage/configuration/config_documentation.md#notify_appservices_from_worker)
+as follows:
 
 ```yaml
 notify_appservices_from_worker: worker_name
@@ -502,11 +504,38 @@ after setting this option in the shared configuration!
 This style of configuration supersedes the legacy `synapse.app.appservice`
 worker application type.
 
+#### Push Notifications
+
+You can designate generic worker to sending push notifications to
+a [push gateway](https://spec.matrix.org/v1.5/push-gateway-api/) such as
+[sygnal](https://github.com/matrix-org/sygnal) and email.
+
+This will stop the main process sending push notifications.
+
+The workers responsible for sending push notifications can be defined using the
+[`pusher_instances`](usage/configuration/config_documentation.md#pusher_instances)
+option. For example:
+
+```yaml
+pusher_instances:
+  - pusher_worker1
+  - pusher_worker2
+```
+
+Multiple workers can be added to this map, in which case the work is balanced
+across them. Ensure the main process and all pusher workers are restarted after changing
+this option.
+
+These workers don't need to accept incoming HTTP requests to send push notifications,
+so no additional reverse proxy configuration is required for pusher workers.
+
+This style of configuration supersedes the legacy `synapse.app.pusher`
+worker application type.
 
 ### `synapse.app.pusher`
 
 It is likely this option will be deprecated in the future and is not recommended for new
-installations. Instead, [use `synapse.app.generic_worker` with the `pusher_instances`](usage/configuration/config_documentation.md#pusher_instances).
+installations. Instead, [use `synapse.app.generic_worker` with the `pusher_instances`](#push-notifications).
 
 Handles sending push notifications to sygnal and email. Doesn't handle any
 REST endpoints itself, but you should set
@@ -547,7 +576,7 @@ Note this worker cannot be load-balanced: only one instance should be active.
 ### `synapse.app.federation_sender`
 
 It is likely this option will be deprecated in the future and not recommended for
-new installations. Instead, [use `synapse.app.generic_worker` with the `federation_sender_instances`](usage/configuration/config_documentation.md#federation_sender_instances). 
+new installations. Instead, [use `synapse.app.generic_worker` with the `federation_sender_instances`](usage/configuration/config_documentation.md#federation_sender_instances).
 
 Handles sending federation traffic to other servers. Doesn't handle any
 REST endpoints itself, but you should set
@@ -606,7 +635,9 @@ expose the `media` resource. For example:
 ```
 
 Note that if running multiple media repositories they must be on the same server
-and you must configure a single instance to run the background tasks, e.g.:
+and you must specify a single instance to run the background tasks in the
+[shared configuration](usage/configuration/config_documentation.md#media_instance_running_background_jobs),
+e.g.:
 
 ```yaml
 media_instance_running_background_jobs: "media-repository-1"