Prepare matrix-registation for (SQLite + Postgres) support

Auto-migration and everything seems to work. It's just that
matrix-registration cannot load the Python modules required
for talking to a Postgres database.

Tracked here: https://github.com/ZerataX/matrix-registration/issues/44

Until this gets fixed, we'll continue default to 'sqlite'.

group_vars/matrix_servers

@@ -1010,6 +1010,12 @@ matrix_postgres_additional_databases: |
       'password': matrix_bot_matrix_reminder_bot_database_password,
     }] if (matrix_bot_matrix_reminder_bot_enabled and matrix_bot_matrix_reminder_bot_database_engine == 'postgres' and matrix_bot_matrix_reminder_bot_database_hostname == 'matrix-postgres') else [])
     +
+    ([{
+      'name': matrix_registration_database_db_name,
+      'username': matrix_registration_database_username,
+      'password': matrix_registration_database_password,
+    }] if (matrix_registration_enabled and matrix_registration_database_engine == 'postgres' and matrix_registration_database_hostname == 'matrix-postgres') else [])
+    +
     ([{
       'name': matrix_appservice_discord_database_db_name,
       'username': matrix_appservice_discord_database_username,
@@ -1291,6 +1297,18 @@ matrix_registration_api_validate_certs: "{{ false if matrix_ssl_retrieval_method
 
 matrix_registration_container_image_self_build: "{{ matrix_architecture != 'amd64' }}"
 
+matrix_registration_systemd_required_services_list: |
+  {{
+    ['docker.service']
+    +
+    (['matrix-postgres.service'] if matrix_postgres_enabled else [])
+  }}
+
+# We'd like to use 'postgres' if matrix_postgres_enabled, but the container image doesn't seem to support that.
+# Learn more here: https://github.com/ZerataX/matrix-registration/issues/44
+matrix_registration_database_engine: 'sqlite'
+matrix_registration_database_password: "{{ matrix_synapse_macaroon_secret_key | password_hash('sha512', 'mx.registr.db') | to_uuid }}"
+
 ######################################################################
 #
 # /matrix-registration

roles/matrix-registration/defaults/main.yml

@@ -32,6 +32,36 @@ matrix_registration_systemd_wanted_services_list: []
 # Takes an "<ip>:<port>" or "<port>" value (e.g. "127.0.0.1:8767"), or empty string to not expose.
 matrix_registration_container_http_host_bind_port: ''
 
+# Database-related configuration fields.
+#
+# To use SQLite, stick to these defaults.
+#
+# To use Postgres:
+# - change the engine (`matrix_registration_database_engine: 'postgres'`)
+# - adjust your database credentials via the `matrix_registration_postgres_*` variables
+matrix_registration_database_engine: 'sqlite'
+
+matrix_registration_sqlite_database_path_local: "{{ matrix_registration_data_path }}/db.sqlite3"
+matrix_registration_sqlite_database_path_in_container: "/data/db.sqlite3"
+
+matrix_registration_database_username: 'matrix_registration'
+matrix_registration_database_password: 'some-password'
+matrix_registration_database_hostname: 'matrix-postgres'
+matrix_registration_database_port: 5432
+matrix_registration_database_db_name: 'matrix_registration'
+
+matrix_registration_database_connection_string: 'postgresql://{{ matrix_registration_database_username }}:{{ matrix_registration_database_password }}@{{ matrix_registration_database_hostname }}:{{ matrix_registration_database_port }}/{{ matrix_registration_database_db_name }}'
+
+# For some reason, matrix-registraiton expects the `db` field to be like this: `sqlite:////data/db.sqlite3`.
+# (seems like one too many slashes, but..)
+matrix_registration_db: "{{
+	{
+		'sqlite': ('sqlite:///' + matrix_registration_sqlite_database_path_in_container),
+		'postgres': matrix_registration_database_connection_string,
+	}[matrix_registration_database_engine]
+}}"
+
+
 # The path at which Matrix Registration will be exposed on `matrix.DOMAIN`
 # (only applies when matrix-nginx-proxy is used).
 matrix_registration_public_endpoint: /matrix-registration

roles/matrix-registration/tasks/setup_install.yml

@@ -1,5 +1,31 @@
 ---
 
+- set_fact:
+    matrix_registration_requires_restart: false
+
+- block:
+    - name: Check if an SQLite database already exists
+      stat:
+        path: "{{ matrix_registration_sqlite_database_path_local }}"
+      register: matrix_registration_sqlite_database_path_local_stat_result
+
+    - block:
+        - set_fact:
+            matrix_postgres_db_migration_request:
+              src: "{{ matrix_registration_sqlite_database_path_local }}"
+              dst: "{{ matrix_registration_database_connection_string }}"
+              caller: "{{ role_path|basename }}"
+              engine_variable_name: 'matrix_registration_database_engine'
+              engine_old: 'sqlite'
+              systemd_services_to_stop: ['matrix-registration.service']
+
+        - import_tasks: "roles/matrix-postgres/tasks/util/migrate_db_to_postgres.yml"
+
+        - set_fact:
+            matrix_registration_requires_restart: true
+      when: "matrix_registration_sqlite_database_path_local_stat_result.stat.exists|bool"
+  when: "matrix_registration_database_engine == 'postgres'"
+
 - name: Ensure matrix-registration paths exist
   file:
     path: "{{ item.path }}"
@@ -61,3 +87,9 @@
   service:
     daemon_reload: yes
   when: "matrix_registration_systemd_service_result.changed|bool"
+
+- name: Ensure matrix-registration.service restarted, if necessary
+  service:
+    name: "matrix-registration.service"
+    state: restarted
+  when: "matrix_registration_requires_restart|bool"

roles/matrix-registration/tasks/validate_config.yml

@@ -18,3 +18,10 @@
   when: "item.old in vars"
   with_items:
     - {'old': 'matrix_registration_docker_repo', 'new': 'matrix_registration_container_image_self_build_repo'}
+
+- name: Fail if Postgres usage attempted
+  fail:
+    msg: >
+      matrix-registration doesn't support using Postgres just yet.
+      Learn more here: https://github.com/ZerataX/matrix-registration/issues/44
+  when: "matrix_registration_database_engine == 'postgres'"

roles/matrix-registration/templates/config.yaml.j2

@@ -3,7 +3,7 @@ server_name: {{ matrix_registration_server_name|to_json }}
 shared_secret: {{ matrix_registration_shared_secret|to_json }}
 admin_secret: {{ matrix_registration_admin_secret|to_json }}
 riot_instance: {{ matrix_registration_riot_instance|to_json }}
-db: 'sqlite:////data/db.sqlite3'
+db: {{ matrix_registration_db|to_json }}
 host: '0.0.0.0'
 port: 5000
 rate_limit: ["100 per day", "10 per minute"]