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

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

@@ -45,6 +45,21 @@ matrix_appservice_slack_appservice_token: ''
 matrix_appservice_slack_homeserver_token: ''
 matrix_appservice_slack_id_token: ''
 
+matrix_appservice_slack_database_engine: nedb
+matrix_appservice_slack_database_username: matrix_appservice_slack
+matrix_appservice_slack_database_password: ~
+matrix_appservice_slack_database_hostname: 'matrix-postgres'
+matrix_appservice_slack_database_port: 5432
+matrix_appservice_slack_database_name: matrix_appservice_slack
+matrix_appservice_slack_database_file: /data
+matrix_appservice_slack_database_connString: >-2
+  {%- if matrix_appservice_slack_database_engine == 'postgres' -%}
+  postgresql://{{ matrix_appservice_slack_database_username }}:{{ matrix_appservice_slack_database_password }}@{{ matrix_appservice_slack_database_hostname }}:{{ matrix_appservice_slack_database_port }}/{{ matrix_appservice_slack_database_name }}?sslmode=disable
+  {%- else if matrix_appservice_slack_database_engine == 'nedb' -%}
+  {{ matrix_appservice_slack_database_engine }}://{{ matrix_appservice_slack_database_file }}
+  {%- endif -%}
+
+
 matrix_appservice_slack_configuration_yaml: "{{ lookup('template', 'templates/config.yaml.j2') }}"
 
 matrix_appservice_slack_configuration_extension_yaml: |

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

@@ -9,4 +9,24 @@
     - "matrix_appservice_slack_control_room_id"
     - "matrix_appservice_slack_appservice_token"
     - "matrix_appservice_slack_homeserver_token"
-    - "matrix_appservice_slack_id_token"
+    - "matrix_appservice_slack_id_token"
+
+- block:
+  - name: Check if a neDB database already exists
+    stat:
+      path: "{{ matrix_appservice_slack_data_path }}/"
+    register: matrix_appservice_slack_nedb_stat_result
+
+  - name: Fail if an neDB database already exists when using Postgres
+    fail:
+      msg: >-2
+        matrix_appservice_slack_database_engine has been set to `postgres` (which is our new default now).
+        However, we've discovered an existing neDB database in {{ matrix_appservice_slack_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_slack_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_slack_data_path }} postgres_connection_string_variable_name=matrix_appservice_slack_database_connString'`)
+        3. Re-run the playbook (`ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start`)
+    when: "matrix_appservice_slack_nedb_stat_result.stat.exists"
+  when: "matrix_appservice_slack_database_engine == 'postgres'"

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

@@ -9,9 +9,11 @@ homeserver:
     url: "{{ matrix_appservice_slack_homeserver_url }}"
     server_name: "{{ matrix_domain }}"
 
+{% if matrix_appservice_slack_database_engine == 'nedb' %}
 dbdir: "/data"
+{% endif %}
 db:
-    engine: "postgres"
-    connectionString: "postgresql://matrix_appservice_slack:{{ matrix_addtional_databases | selectattr('name', 'equalto', 'matrix_appservice_slack') | map(attribute='pass') | first }}@{{ matrix_postgres_connection_hostname }}/matrix_appservice_slack"
+    engine: "{{ matrix_appservice_slack_database_engine }}"
+    connectionString: {{ matrix_appservice_slack_database_connString | to_json }}
 
 matrix_admin_room: "{{ matrix_appservice_slack_control_room_id }}"