Add support for importing an existing Postgres database

roles/matrix-server/tasks/import_postgres.yml

@@ -0,0 +1,53 @@
+---
+
+# Pre-checks
+
+- name: Fail if playbook called incorrectly
+  fail: msg="The `server_path_postgres_dump` variable needs to be provided to this playbook, via --extra-vars"
+  when: "server_path_postgres_dump is not defined or server_path_postgres_dump.startswith('<')"
+
+- name: Check if the provided Postgres dump file exists
+  stat: path="{{ server_path_postgres_dump }}"
+  register: result_server_path_postgres_dump_stat
+
+- name: Fail if provided Postgres dump file doesn't exists
+  fail: msg="File cannot be found on the local machine at {{ server_path_postgres_dump }}"
+  when: not result_server_path_postgres_dump_stat.stat.exists
+
+- include: tasks/util/detect_existing_postgres_version.yml
+
+- name: Abort, if no existing Postgres version detected
+  fail: msg="Could not find existing Postgres installation"
+  when: "not matrix_postgres_detected_existing"
+
+
+# Defaults
+
+- name: Set postgres_start_wait_time, if not provided
+  set_fact:
+    postgres_start_wait_time: 15
+  when: "postgres_start_wait_time|default('') == ''"
+
+
+# Actual import work
+
+- name: Ensure matrix-postgres is started
+  service: name=matrix-postgres state=started daemon_reload=yes
+
+- name: Wait a bit, so that Postgres can start
+  wait_for:
+    timeout: "{{ postgres_start_wait_time }}"
+  delegate_to: 127.0.0.1
+  become: false
+
+- name: Perform Postgres database import
+  command: |
+    /usr/bin/docker run --rm --name matrix-postgres-import \
+    --network={{ matrix_docker_network }} \
+    --env-file={{ matrix_environment_variables_data_path }}/env-postgres-pgsql-docker \
+    -v {{ server_path_postgres_dump }}:{{ server_path_postgres_dump }}:ro \
+    --entrypoint=/bin/sh
+    {{ matrix_postgres_docker_image_latest }}
+    -c 'cat {{ server_path_postgres_dump }} | \
+    {{ 'gunzip |' if server_path_postgres_dump.endswith('.gz') else '' }}
+    psql -v ON_ERROR_STOP=1 -h matrix-postgres'

roles/matrix-server/tasks/main.yml

@@ -3,6 +3,11 @@
 - include: tasks/setup/main.yml
   when: run_setup
 
+- include: tasks/import_postgres.yml
+  tags:
+    - import-postgres
+  when: run_import_postgres
+
 - include: tasks/upgrade_postgres.yml
   tags:
     - upgrade-postgres