Rework matrix_mautrix_twitter_database_* variables a bit

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1682

Previously, when matrix-postgres was disabled, we were setting
`matrix_mautrix_twitter_database_engine` to an invalid empty value.

Now, we always hardcode `matrix_mautrix_twitter_database_engine: postgres`,
but set/unset the database hostname and password values instead.

group_vars/matrix_servers

@@ -558,10 +558,8 @@ matrix_mautrix_twitter_homeserver_token: "{{ matrix_homeserver_generic_secret_ke
 
 matrix_mautrix_twitter_login_shared_secret: "{{ matrix_synapse_ext_password_provider_shared_secret_auth_shared_secret if matrix_synapse_ext_password_provider_shared_secret_auth_enabled else '' }}"
 
-# We'd like to force-set people with external Postgres to SQLite, so the bridge role can complain
-# and point them to a migration path.
-matrix_mautrix_twitter_database_engine: "{{ 'postgres' if matrix_postgres_enabled else '' }}"
-matrix_mautrix_twitter_database_password: "{{ matrix_homeserver_generic_secret_key | password_hash('sha512', 'mau.twt.db') | to_uuid }}"
+matrix_mautrix_twitter_database_hostname: "{{ 'matrix-postgres' if matrix_postgres_enabled else '' }}"
+matrix_mautrix_twitter_database_password: "{{ matrix_homeserver_generic_secret_key | password_hash('sha512', 'mau.twt.db') | to_uuid if matrix_postgres_enabled else '' }}"
 
 ######################################################################
 #

roles/matrix-bridge-mautrix-twitter/defaults/main.yml

@@ -42,8 +42,8 @@ matrix_mautrix_twitter_homeserver_token: ''
 matrix_mautrix_twitter_database_engine: 'postgres'
 
 matrix_mautrix_twitter_database_username: 'matrix_mautrix_twitter'
-matrix_mautrix_twitter_database_password: 'some-password'
-matrix_mautrix_twitter_database_hostname: 'matrix-postgres'
+matrix_mautrix_twitter_database_password: ''
+matrix_mautrix_twitter_database_hostname: ''
 matrix_mautrix_twitter_database_port: 5432
 matrix_mautrix_twitter_database_name: 'matrix_mautrix_twitter'
 

roles/matrix-bridge-mautrix-twitter/tasks/validate_config.yml

@@ -8,11 +8,5 @@
   with_items:
     - "matrix_mautrix_twitter_appservice_token"
     - "matrix_mautrix_twitter_homeserver_token"
-
-- name: Fail if database is not defined
-  fail:
-    msg: >-
-      You need to define a need to set `matrix_mautrix_twitter_database_engine: postgres` and redefine the other `matrix_mautrix_twitter_database_*` variables
-  when: "vars[item] == ''"
-  with_items:
-    - "matrix_mautrix_twitter_database_engine"
+    - "matrix_mautrix_twitter_database_hostname"
+    - "matrix_mautrix_twitter_database_password"