From cbee084ac19b663b965847f60e95a0c020c7111b Mon Sep 17 00:00:00 2001
From: Slavi Pantaleev <slavi@devture.com>
Date: Mon, 28 May 2018 14:47:09 +0300
Subject: [PATCH] Use Postgres 10.x by default (only for new installs)

This playbook just tries to avoid trying to setup a Postgres 10
database with existing 9.x files, as that makes Postgres complain.

Due to this, existing installs (still on 9.x) are detected
and left on Postgres 9.x.
They need to be upgraded to Postgres 10.x manually.
---
 roles/matrix-server/defaults/main.yml         |  7 ++++-
 roles/matrix-server/tasks/setup_postgres.yml  | 31 ++++++++++++++++++-
 .../systemd/matrix-postgres.service.j2        |  2 +-
 .../usr-local-bin/matrix-postgres-cli.j2      |  2 +-
 4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/roles/matrix-server/defaults/main.yml b/roles/matrix-server/defaults/main.yml
index 9ba39dd2d..de7e01ddf 100644
--- a/roles/matrix-server/defaults/main.yml
+++ b/roles/matrix-server/defaults/main.yml
@@ -40,7 +40,11 @@ matrix_coturn_base_path: "{{ matrix_base_data_path }}/coturn"
 matrix_coturn_config_path: "{{ matrix_coturn_base_path }}/turnserver.conf"
 matrix_scratchpad_dir: "{{ matrix_base_data_path }}/scratchpad"
 
-docker_postgres_image: "postgres:9.6.8-alpine"
+
+docker_postgres_image_v9: "postgres:9.6.8-alpine"
+docker_postgres_image_v10: "postgres:10.4-alpine"
+docker_postgres_image_latest: "{{ docker_postgres_image_v10 }}"
+
 docker_matrix_image: "matrixdotorg/synapse:v0.30.0"
 docker_nginx_image: "nginx:1.13.12-alpine"
 docker_riot_image: "avhost/docker-matrix-riot:v0.15.4"
@@ -48,6 +52,7 @@ docker_s3fs_image: "xueshanf/s3fs:latest"
 docker_goofys_image: "cloudproto/goofys:latest"
 docker_coturn_image: "instrumentisto/coturn:4.5.0.7"
 
+
 # To avoid Synapse's macaroon secret key from changing every time
 # a new config is built from scratch, you can specify one here.
 matrix_synapse_macaroon_secret_key: null
diff --git a/roles/matrix-server/tasks/setup_postgres.yml b/roles/matrix-server/tasks/setup_postgres.yml
index c52e0b6a5..a231b902f 100644
--- a/roles/matrix-server/tasks/setup_postgres.yml
+++ b/roles/matrix-server/tasks/setup_postgres.yml
@@ -4,10 +4,39 @@
 # Generic tasks, no matter what kind of server we're using (internal/external)
 #
 
+- name: Determine existing Postgres version (check PG_VERSION file)
+  stat:
+    path: "{{ matrix_postgres_data_path }}/PG_VERSION"
+  register: result_pg_version_stat
+
+- name: Determine existing Postgres version (read PG_VERSION file)
+  slurp:
+    src: "{{ matrix_postgres_data_path }}/PG_VERSION"
+  register: result_pg_version
+  when: "result_pg_version_stat.stat.exists"
+
+- name: Determine existing Postgres version (default to empty)
+  set_fact:
+    pg_version: ""
+
+- name: Determine existing Postgres version (make sense of PG_VERSION file)
+  set_fact:
+    pg_version: "{{ result_pg_version['content']|b64decode|replace('\n', '') }}"
+  when: "result_pg_version_stat.stat.exists"
+
+- name: Determine Postgres version to use (default to latest)
+  set_fact:
+    docker_postgres_image_to_use: "{{ docker_postgres_image_latest }}"
+
+- name: Determine Postgres version to use (use 9.x, if detected)
+  set_fact:
+    docker_postgres_image_to_use: "{{ docker_postgres_image_v9 }}"
+  when: "pg_version.startswith('9.')"
+
 # Even if we don't run the internal server, we still need this for running the CLI
 - name: Ensure postgres Docker image is pulled
   docker_image:
-    name: "{{ docker_postgres_image }}"
+    name: "{{ docker_postgres_image_to_use }}"
 
 - name: Ensure Postgres environment variables file created
   template:
diff --git a/roles/matrix-server/templates/systemd/matrix-postgres.service.j2 b/roles/matrix-server/templates/systemd/matrix-postgres.service.j2
index 846d73558..f0bc4bd4f 100644
--- a/roles/matrix-server/templates/systemd/matrix-postgres.service.j2
+++ b/roles/matrix-server/templates/systemd/matrix-postgres.service.j2
@@ -14,7 +14,7 @@ ExecStart=/usr/bin/docker run --rm --name matrix-postgres \
 			--env-file={{ matrix_environment_variables_data_path }}/env-postgres-server-docker \
 			-v {{ matrix_postgres_data_path }}:/var/lib/postgresql/data \
 			-v /etc/passwd:/etc/passwd:ro \
-			{{ docker_postgres_image }}
+			{{ docker_postgres_image_to_use }}
 ExecStop=-/usr/bin/docker stop matrix-postgres
 ExecStop=-/usr/bin/docker rm matrix-postgres
 Restart=always
diff --git a/roles/matrix-server/templates/usr-local-bin/matrix-postgres-cli.j2 b/roles/matrix-server/templates/usr-local-bin/matrix-postgres-cli.j2
index 2e6a15ce8..f23792765 100644
--- a/roles/matrix-server/templates/usr-local-bin/matrix-postgres-cli.j2
+++ b/roles/matrix-server/templates/usr-local-bin/matrix-postgres-cli.j2
@@ -7,5 +7,5 @@ docker run \
 	{% if not matrix_postgres_use_external %}
 	--link=matrix-postgres:{{ matrix_postgres_connection_hostname }} \
 	{% endif %}
-	{{ docker_postgres_image }} \
+	{{ docker_postgres_image_to_use }} \
 	psql -h {{ matrix_postgres_connection_hostname }}
\ No newline at end of file