Make Synapse configuration extensible

CHANGELOG.md

@@ -1,3 +1,18 @@
+# 2019-08-22
+
+## Extensible Synapse configuration
+
+Previously, we had to create custom Ansible variables for each and every Synapse setting.
+This lead to too much effort (and configuration ugliness) to all of Synapse's settings, so naturally, not all features of Synapse could be controlled through the playbook.
+
+From now on, you can extend/override the Synapse server's configuration by making use of the `matrix_synapse_configuration_extension_yaml` variable.
+This should be enough for most customization needs.
+
+If you need even more power, you can now also take full control and override `matrix_synapse_configuration` (or `matrix_synapse_configuration_yaml`) directly.
+
+Learn more here in [Configuring Synapse](docs/configuring-playbook-synapse.md).
+
+
 # 2019-08-21
 
 ## Slack bridging support

docs/configuring-playbook-synapse.md

@@ -0,0 +1,18 @@
+# Configuring Synapse (optional)
+
+By default, this playbook configures the [Synapse](https://github.com/matrix-org/synapse) Matrix server, so that it works for the general case.
+If that's enough for you, you can skip this document.
+
+The playbook provides lots of customization variables you could use to change Synapse's settings.
+
+Their defaults are defined in [`roles/matrix-synapse/defaults/main.yml`](../roles/matrix-synapse/defaults/main.yml) and they ultimately end up in the generated `/matrix/synapse/config/homeserver.yaml` file (on the server). This file is generated from the [`roles/matrix-synapse/templates/synapse/homeserver.yaml.j2`](../roles/matrix-synapse/templates/synapse/homeserver.yaml.j2) template.
+
+**If there's an existing variable** which controls a setting you wish to change, you can simply define that variable in your configuration file (`inventory/host_vars/matrix.<your-domain>/vars.yml`) and [re-run the playbook](installing.md) to apply the changes.
+
+Alternatively, **if there is no pre-defined variable** for a Synapse setting you wish to change:
+
+- you can either **request a variable to be created** (or you can submit such a contribution yourself). Keep in mind that it's **probably not a good idea** to create variables for each one of Synapse's various settings that rarely get used.
+
+- or, you can **extend and override the default configuration** ([`homeserver.yaml.j2`](../roles/matrix-synapse/templates/synapse/homeserver.yaml.j2)) by making use of the `matrix_synapse_configuration_extension_yaml` variable. You can find information about this in [`roles/matrix-synapse/defaults/main.yml`](../roles/matrix-synapse/defaults/main.yml).
+
+- or, if extending the configuration is still not powerful enough for your needs, you can **override the configuration completely** using `matrix_synapse_configuration` (or `matrix_synapse_configuration_yaml`). You can find information about this in [`roles/matrix-synapse/defaults/main.yml`](../roles/matrix-synapse/defaults/main.yml).

docs/configuring-playbook.md

@@ -34,6 +34,8 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 
 ### Core service adjustments
 
+- [Configuring Synapse](configuring-playbook-synapse.md) (optional)
+
 - [Storing Matrix media files on Amazon S3](configuring-playbook-s3.md) (optional)
 
 - [Using an external PostgreSQL server](configuring-playbook-external-postgres.md) (optional)

roles/matrix-synapse/defaults/main.yml

@@ -295,3 +295,33 @@ matrix_synapse_room_list_publication_rules:
     action: allow
 
 matrix_synapse_default_room_version: "4"
+
+# Default Synapse configuration template which covers the generic use case.
+# You can customize it by controlling the various variables inside it.
+#
+# For a more advanced customization, you can extend the default (see `matrix_synapse_configuration_extension_yaml`)
+# or completely replace this variable with your own template.
+matrix_synapse_configuration_yaml: "{{ lookup('template', 'templates/synapse/homeserver.yaml.j2') }}"
+
+matrix_synapse_configuration_extension_yaml: |
+  # Your custom YAML configuration for Synapse goes here.
+  # This configuration extends the default starting configuration (`matrix_synapse_configuration_yaml`).
+  #
+  # You can override individual variables from the default configuration, or introduce new ones.
+  #
+  # If you need something more special, you can take full control by
+  # completely redefining `matrix_synapse_configuration_yaml`.
+  #
+  # Example configuration extension follows:
+  #
+  # server_notices:
+  #   system_mxid_localpart: notices
+  #   system_mxid_display_name: "Server Notices"
+  #   system_mxid_avatar_url: "mxc://server.com/oumMVlgDnLYFaPVkExemNVVZ"
+  #   room_name: "Server Notices"
+
+matrix_synapse_configuration_extension: "{{ matrix_synapse_configuration_extension_yaml|from_yaml if matrix_synapse_configuration_extension_yaml|from_yaml is mapping else {} }}"
+
+# Holds the final Synapse configuration (a combination of the default and its extension).
+# You most likely don't need to touch this variable. Instead, see `matrix_synapse_configuration_yaml`.
+matrix_synapse_configuration: "{{ matrix_synapse_configuration_yaml|from_yaml|combine(matrix_synapse_configuration_extension, recursive=True) }}"

roles/matrix-synapse/tasks/synapse/setup_install.yml

@@ -53,10 +53,12 @@
   when: "not matrix_synapse_signing_key_stat.stat.exists"
 
 - name: Ensure Synapse homeserver config installed
-  template:
-    src: "{{ matrix_synapse_template_synapse_homeserver }}"
+  copy:
+    content: "{{ matrix_synapse_configuration|to_nice_yaml }}"
     dest: "{{ matrix_synapse_config_dir_path }}/homeserver.yaml"
     mode: 0644
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_username }}"
 
 - name: Ensure Synapse log config installed
   template: