Add support for importing an existing Postgres database

docs/importing-postgres.md

@@ -0,0 +1,24 @@
+# Importing an existing Postgres database from another installation (optional)
+
+Run this if you'd like to import your database from a previous installation of Matrix Synapse.
+(don't forget to import your `media_store` files as well - see [the restoring media store guide](restoring-media-store.md)).
+
+
+## Prerequisites
+
+For this to work, **the database name in Postgres must match** what this playbook uses.
+This playbook uses a Postgres database name of `homeserver` by default (controlled by the `matrix_postgres_db_name` variable).
+If your database name differs, be sure to change `matrix_postgres_db_name` to your desired name and to re-run the playbook before proceeding.
+
+The playbook supports importing Postgres dump files in **text** (e.g. `pg_dump > dump.sql`) or **gzipped** formats (e.g. `pg_dump | gzip -c > dump.sql.gz`).
+
+Before doing the actual import, **you need to upload your Postgres dump file to the server**.
+
+
+## Importing
+
+To import, run this command (make sure to replace `<server-path-to-postgres-dump.sql>` with a file path on your server):
+
+	ansible-playbook -i inventory/hosts setup.yml --extra-vars='server_path_postgres_dump=<server-path-to-postgres-dump.sql>' --tags=import-postgres
+
+**Note**: `<server-path-to-postgres-dump.sql>` must be a file path to a Postgres dump file on the server (not on your local machine!).

docs/installing.md

@@ -19,6 +19,8 @@ After installing, but before starting the services, you may want to do additiona
 
 - [Importing an existing SQLite database (from another installation)](importing-sqlite.md) (optional)
 
+- [Importing an existing Postgres database (from another installation)](importing-postgres.md) (optional)
+
 - [Restoring `media_store` data files from an existing installation](restoring-media-store.md) (optional)
 
 

roles/matrix-server/defaults/main.yml

@@ -418,6 +418,7 @@ matrix_ssl_log_dir_path: "{{ matrix_ssl_base_path }}/log"
 
 # Variables to Control which parts of the role run.
 run_setup: true
+run_import_postgres: true
 run_upgrade_postgres: true
 run_start: true
 run_register_user: true

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