add postgres support mx-appservice-[slack|irc] with fallback to nedb in role and migration notice

roles/matrix-bridge-appservice-irc/defaults/main.yml

@@ -16,6 +16,20 @@ matrix_appservice_irc_homeserver_domain: '{{ matrix_domain }}'
 matrix_appservice_irc_homeserver_enablePresence: true
 matrix_appservice_irc_appservice_address: 'http://matrix-appservice-irc:9999'
 
+matrix_appservice_irc_database_engine: nedb
+matrix_appservice_irc_database_username: matrix_appservice_irc
+matrix_appservice_irc_database_password: ~
+matrix_appservice_irc_database_hostname: 'matrix-postgres'
+matrix_appservice_irc_database_port: 5432
+matrix_appservice_irc_database_name: matrix_appservice_irc
+matrix_appservice_irc_databasa
+matrix_appservice_irc_database_connString: >-2
+  {%- if matrix_appservice_irc_database_engine == 'postgres' -%}
+  postgresql://{{ matrix_appservice_irc_database_username }}:{{ matrix_appservice_irc_database_password }}@{{ matrix_appservice_irc_database_hostname }}:{{ matrix_appservice_irc_database_port }}/{{ matrix_appservice_irc_database_name }}?sslmode=disable
+  {%- else if matrix_appservice_irc_database_engine == 'nedb' -%}
+  {{ matrix_appservice_irc_database_engine }}://{{ matrix_appservice_irc_database_file }}
+  {%- endif -%}
+
 matrix_appservice_irc_ircService_servers: []
 
 # Example of `matrix_appservice_irc_ircService_servers` with one server (and all its options):

roles/matrix-bridge-appservice-irc/tasks/validate_config.yml

@@ -33,3 +33,23 @@
   when: "item.old in vars"
   with_items:
     - {'old': 'matrix_appservice_irc_container_expose_client_server_api_port', 'new': '<superseded by matrix_appservice_irc_container_http_host_bind_port>'}
+
+- block:
+  - name: Check if a neDB database already exists
+    stat:
+      path: "{{ matrix_appservice_irc_data_path }}/"
+    register: matrix_appservice_irc_nedb_stat_result
+
+  - name: Fail if an neDB database already exists when using Postgres
+    fail:
+      msg: >-2
+        matrix_appservice_irc_database_engine has been set to `postgres` (which is our new default now).
+        However, we've discovered an existing neDB database in {{ matrix_appservice_irc_data_path }}/.
+        It appears that you've been using this bridge with the neDB engine until now.
+        To continue using neDB, opt into it explicitly: add `matrix_appservice_irc_database_engine: nedb` to your vars.yml file and re-run this same command.
+        Alternatively, to migrate your existing neDB database to Postgres:
+        1. Stop all services (`ansible-playbook -i inventory/hosts setup.yml --tags=stop`)
+        2. Import the neDB database into Postgres (`ansible-playbook -v -i inventory/hosts setup.yml --tags=import-generic-sqlite-db --extra-vars='sqlite_database_path={{ matrix_appservice_irc_data_path }} postgres_connection_string_variable_name=matrix_appservice_irc_database_connString'`)
+        3. Re-run the playbook (`ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start`)
+    when: "matrix_appservice_irc_nedb_stat_result.stat.exists"
+  when: "matrix_appservice_irc_database_engine == 'postgres'"

roles/matrix-bridge-appservice-irc/templates/config.yaml.j2

@@ -127,8 +127,8 @@ advanced:
 # Use an external database to store bridge state.
 database:
   # database engine (must be 'postgres' or 'nedb'). Default: nedb
-  engine: "postgres"
+  engine: {{ matrix_appservice_irc_database_engine }}
   # Either a PostgreSQL connection string, or a path to the NeDB storage directory.
   # For postgres, it must start with postgres://
   # For NeDB, it must start with nedb://. The path is relative to the project directory.
-  connectionString: "postgres://matrix_appservice_irc:{{ matrix_addtional_databases | selectattr('name', 'equalto', 'matrix_appservice_irc') | map(attribute='pass') | first }}@{{ matrix_postgres_connection_hostname }}/matrix_appservice_irc"
+  connectionString: {{ matrix_appservice_irc_database_connString | to_json }}