From d5f4c17146dbe87d44770dc9dbf215b24eb2375b Mon Sep 17 00:00:00 2001
From: Aine <aine@etke.cc>
Date: Thu, 14 Apr 2022 18:06:54 +0300
Subject: [PATCH] matrix-backup-borg: integrate postgres backups, add extended
 borgmatic configuration

---
 group_vars/matrix_servers                     | 26 ++++++++--
 roles/matrix-backup-borg/defaults/main.yml    | 48 +++++++++++++++----
 .../tasks/setup_install.yml                   |  9 ++--
 .../util/detect_existing_postgres_version.yml | 42 ++++++++++++++++
 .../templates/config.yaml.j2                  | 10 ++++
 setup.yml                                     |  2 +-
 6 files changed, 121 insertions(+), 16 deletions(-)
 create mode 100644 roles/matrix-backup-borg/tasks/util/detect_existing_postgres_version.yml

diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 85b8a7013..91324025e 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -1081,13 +1081,33 @@ matrix_bot_mjolnir_systemd_required_services_list: |
 ######################################################################
 
 matrix_backup_borg_enabled: false
+matrix_backup_borg_container_image_self_build: "{{ matrix_architecture not in ['amd64', 'arm32', 'arm64'] }}"
+matrix_backup_borg_postgresql_enabled: "{{ matrix_postgres_enabled }}"
+matrix_backup_borg_postgresql_databases_hostname: "{{ matrix_postgres_connection_hostname }}"
+matrix_backup_borg_postgresql_databases_username: "{{ matrix_postgres_connection_username }}"
+matrix_backup_borg_postgresql_databases_password: "{{ matrix_postgres_connection_password }}"
+matrix_backup_borg_postgresql_databases_port: "{{ matrix_postgres_connection_port }}"
+matrix_backup_borg_postgresql_databases: |
+  {{
+    (([{
+        'name': matrix_synapse_database_database
+    }] if (matrix_synapse_enabled and matrix_synapse_database_database == matrix_postgres_db_name and matrix_synapse_database_host == 'matrix-postgres') else [])
+    +
+    matrix_postgres_additional_databases)|map(attribute='name')|list
+  }}
 matrix_backup_borg_location_source_directories:
   - "{{ matrix_base_data_path }}"
 matrix_backup_borg_location_exclude_patterns: |
   {{
-    {
-      'synapse': ["{{ matrix_synapse_media_store_path }}/local_thumbnails", "{{ matrix_synapse_media_store_path }}/remote_thumbnail", "{{ matrix_synapse_media_store_path }}/url_cache", "{{ matrix_synapse_media_store_path }}/url_cache_thumbnails"],
-    }[matrix_homeserver_implementation]
+    ([matrix_synapse_media_store_path + '/local_thumbnails', matrix_synapse_media_store_path + '/remote_thumbnail', matrix_synapse_media_store_path + '/url_cache', matrix_synapse_media_store_path + '/url_cache_thumbnails'] if matrix_homeserver_implementation == 'synapse' else [])
+    +
+    ([matrix_postgres_data_path] if matrix_postgres_enabled else [])
+  }}
+matrix_backup_borg_systemd_required_services_list: |
+  {{
+    ['docker.service']
+    +
+    (['matrix-postgres.service'] if matrix_postgres_enabled else [])
   }}
 
 ######################################################################
diff --git a/roles/matrix-backup-borg/defaults/main.yml b/roles/matrix-backup-borg/defaults/main.yml
index c8a09f7f4..374b5befa 100644
--- a/roles/matrix-backup-borg/defaults/main.yml
+++ b/roles/matrix-backup-borg/defaults/main.yml
@@ -1,18 +1,18 @@
 ---
 matrix_backup_borg_enabled: true
 
-matrix_backup_borg_container_image_self_build: false
-matrix_backup_borg_docker_repo: "https://github.com/borgmatic-collective/docker-borgmatic"
-matrix_backup_borg_docker_src_files_path: "{{ matrix_base_data_path }}/borg/docker-src"
-
-matrix_backup_borg_version: latest
-matrix_backup_borg_docker_image: "{{ matrix_backup_borg_docker_image_name_prefix }}etke.cc/borgmatic:{{ matrix_backup_borg_version }}"
-matrix_backup_borg_docker_image_name_prefix: "{{ 'localhost/' if matrix_backup_borg_container_image_self_build else 'registry.gitlab.com/' }}"
-matrix_backup_borg_docker_image_force_pull: "{{ matrix_backup_borg_docker_image.endswith(':latest') }}"
-
 matrix_backup_borg_base_path: "{{ matrix_base_data_path }}/backup-borg"
 matrix_backup_borg_config_path: "{{ matrix_backup_borg_base_path }}/config"
 
+matrix_backup_borg_container_image_self_build: false
+matrix_backup_borg_docker_repo: "https://github.com/borgmatic-collective/docker-borgmatic"
+matrix_backup_borg_docker_src_files_path: "{{ matrix_backup_borg_base_path }}/docker-src"
+
+matrix_backup_borg_version: ""
+matrix_backup_borg_docker_image: "{{ matrix_backup_borg_docker_image_name_prefix }}etke.cc/borgmatic:{{ matrix_backup_borg_version }}"
+matrix_backup_borg_docker_image_name_prefix: "{{ 'localhost/' if matrix_backup_borg_container_image_self_build else 'registry.gitlab.com/' }}"
+matrix_backup_borg_docker_image_force_pull: "{{ matrix_backup_borg_docker_image.endswith(':latest') or matrix_backup_borg_version|default('') == '' }}"
+
 # A list of extra arguments to pass to the container
 matrix_backup_borg_container_extra_arguments: []
 
@@ -28,6 +28,14 @@ matrix_backup_borg_schedule: "*-*-* 04:00:00"
 # what directories should be added to backup
 matrix_backup_borg_location_source_directories: []
 
+# postgres db backup
+matrix_backup_borg_postgresql_enabled: true
+matrix_backup_borg_postgresql_databases: []
+matrix_backup_borg_postgresql_databases_hostname: "matrix-postgres"
+matrix_backup_borg_postgresql_databases_username: "matrix"
+matrix_backup_borg_postgresql_databases_password: ""
+matrix_backup_borg_postgresql_databases_port: 5432
+
 # target repositories
 matrix_backup_borg_location_repositories: []
 
@@ -61,3 +69,25 @@ matrix_backup_borg_retention_keep_yearly: 2
 
 # retention prefix
 matrix_backup_borg_retention_prefix: "matrix-"
+
+# Default borgmatic configuration template which covers the generic use case.
+# You can customize it by controlling the various variables inside it.
+#
+# For a more advanced customization, you can extend the default (see `matrix_backup_borg_configuration_extension_yaml`)
+# or completely replace this variable with your own template.
+matrix_backup_borg_configuration_yaml: "{{ lookup('template', 'templates/config.yaml.j2') }}"
+
+matrix_backup_borg_configuration_extension_yaml: |
+  # Your custom YAML configuration for borgmatic goes here.
+  # This configuration extends the default starting configuration (`matrix_borg_configuration_yaml`).
+  #
+  # You can override individual variables from the default configuration, or introduce new ones.
+  #
+  # If you need something more special, you can take full control by
+  # completely redefining `matrix_backup_borg_configuration_yaml`.
+
+matrix_backup_borg_configuration_extension: "{{ matrix_backup_borg_configuration_extension_yaml|from_yaml if matrix_backup_borg_configuration_extension_yaml|from_yaml is mapping else {} }}"
+
+# Holds the final borgmatic configuration (a combination of the default and its extension).
+# You most likely don't need to touch this variable. Instead, see `matrix_backup_borg_configuration_yaml`.
+matrix_backup_borg_configuration: "{{ matrix_backup_borg_configuration_yaml|from_yaml|combine(matrix_backup_borg_configuration_extension, recursive=True) }}"
diff --git a/roles/matrix-backup-borg/tasks/setup_install.yml b/roles/matrix-backup-borg/tasks/setup_install.yml
index 90757a803..9c34c53f1 100644
--- a/roles/matrix-backup-borg/tasks/setup_install.yml
+++ b/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 }}"
diff --git a/roles/matrix-backup-borg/tasks/util/detect_existing_postgres_version.yml b/roles/matrix-backup-borg/tasks/util/detect_existing_postgres_version.yml
new file mode 100644
index 000000000..0d50d93f5
--- /dev/null
+++ b/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 == ''"
diff --git a/roles/matrix-backup-borg/templates/config.yaml.j2 b/roles/matrix-backup-borg/templates/config.yaml.j2
index 89b6ab7d4..8ac2a8b2f 100644
--- a/roles/matrix-backup-borg/templates/config.yaml.j2
+++ b/roles/matrix-backup-borg/templates/config.yaml.j2
@@ -26,6 +26,16 @@ consistency:
     - archives
 
 hooks:
+{% if matrix_backup_borg_postgresql_enabled %}
+  postgresql_databases:
+  {% for database in matrix_backup_borg_postgresql_databases %}
+  - name: {{ database }}
+    hostname: {{ matrix_backup_borg_postgresql_databases_hostname }}
+    username: {{ matrix_backup_borg_postgresql_databases_username }}
+    password: {{ matrix_backup_borg_postgresql_databases_password }}
+    port: {{ matrix_backup_borg_postgresql_databases_port }}
+  {% endfor %}
+{% endif %}
   after_backup:
     - echo "Backup created."
   on_error:
diff --git a/setup.yml b/setup.yml
index 52079e32c..de86665b6 100755
--- a/setup.yml
+++ b/setup.yml
@@ -13,7 +13,6 @@
     - matrix-postgres
     - matrix-redis
     - matrix-corporal
-    - matrix-backup-borg
     - matrix-bridge-appservice-discord
     - matrix-bridge-appservice-slack
     - matrix-bridge-appservice-webhooks
@@ -62,4 +61,5 @@
     - matrix-aux
     - matrix-postgres-backup
     - matrix-prometheus-postgres-exporter
+    - matrix-backup-borg
     - matrix-common-after