matrix-backup-borg: integrate postgres backups, add extended borgmatic configuration

roles/matrix-backup-borg/tasks/setup_install.yml

@@ -1,4 +1,7 @@
 ---
+- import_tasks: "{{ role_path }}/tasks/util/detect_existing_postgres_version.yml"
+  when: 'matrix_backup_borg_enabled|bool and matrix_backup_borg_postgresql_enabled|bool and matrix_postgres_backup_postgres_data_path != ""'
+
 - name: Ensure borg paths exist
   file:
     path: "{{ item.path }}"
@@ -11,9 +14,9 @@
     - {path: "{{ matrix_backup_borg_docker_src_files_path }}", when: true}
   when: "item.when|bool"
 
-- name: Ensure borg config is created
-  template:
-    src: "{{ role_path }}/templates/config.yaml.j2"
+- name: Ensure borgmatic config is created
+  copy:
+    content: "{{ matrix_backup_borg_configuration|to_nice_yaml(indent=2, width=999999) }}"
     dest: "{{ matrix_backup_borg_config_path }}/config.yaml"
     owner: "{{ matrix_user_username }}"
     group: "{{ matrix_user_groupname }}"

roles/matrix-backup-borg/tasks/util/detect_existing_postgres_version.yml

@@ -0,0 +1,42 @@
+---
+
+# This utility aims to determine if there is some existing Postgres version in use or not.
+# If there is, it also tries to detect the Docker image that corresponds to that version.
+
+- name: Initialize Postgres version determination variables (default to empty)
+  set_fact:
+    matrix_backup_borg_postgresql_detection_pg_version_path: "{{ matrix_postgres_data_path }}/PG_VERSION"
+    matrix_backup_borg_postgresql_detected_existing: false
+    matrix_backup_borg_postgresql_detected_version: ""
+    matrix_backup_borg_version: ""
+
+- name: Determine existing Postgres version (check PG_VERSION file)
+  stat:
+    path: "{{ matrix_backup_borg_postgresql_detection_pg_version_path }}"
+  register: result_pg_version_stat
+
+- set_fact:
+    matrix_backup_borg_postgresql_detected_existing: true
+  when: "result_pg_version_stat.stat.exists"
+
+- name: Determine existing Postgres version (read PG_VERSION file)
+  slurp:
+    src: "{{ matrix_backup_borg_postgresql_detection_pg_version_path }}"
+  register: result_pg_version
+  when: matrix_backup_borg_postgresql_detected_existing|bool
+
+- name: Determine existing Postgres version (make sense of PG_VERSION file)
+  set_fact:
+    matrix_backup_borg_postgresql_detected_version: "{{ result_pg_version['content']|b64decode|replace('\n', '') }}"
+  when: matrix_backup_borg_postgresql_detected_existing|bool
+
+- name: Determine corresponding Docker image version to detected version
+  set_fact:
+    matrix_backup_borg_version: "{{ matrix_backup_borg_postgresql_detected_version }}"
+  when: "matrix_backup_borg_postgresql_detected_version == '12' or matrix_backup_borg_postgresql_detected_version.startswith('12.') or matrix_backup_borg_postgresql_detected_version == '13' or matrix_backup_borg_postgresql_detected_version.startswith('13.') or matrix_backup_borg_postgresql_detected_version == '14' or matrix_backup_borg_postgresql_detected_version.startswith('14.')"
+
+- name: Fail if existing Postgres version is not supported by borgmatic docker image
+  fail:
+    msg: >-
+      Your Postgres v{{ matrix_backup_borg_postgresql_detected_version }} is not supported.
+  when: "matrix_backup_borg_version == ''"