From 7132acbd3b82fd22f3ff88f313b12f1e77a76c24 Mon Sep 17 00:00:00 2001
From: Georgina <georgina.shippey@bbc.co.uk>
Date: Wed, 22 May 2019 17:05:01 +0000
Subject: [PATCH] Allow remote detection of repo sync status

If a repo container and its data are deleted and recreated then it is
not currently possible for a loadbalancer healthcheck to differentiate
between an empty repo server and a correctly synchronised one.

This patch creates a file 'repo-sync-complete' as part of the process
of synchronising repo contents from master repo servers to slaves. The
presence of this file on the slave can then be used as the loadbalancer
healthcheck to ensure that repo contents are only served once sync has
completed.

In addition, this patch ensures that synchronisation occurs from the
master to a reprovisioned slave by triggering a master repo server lsyncd
restart handler during the initial setup of the slave repo server.
Currently, a freshly provisioned repo server will remain empty
for an indeterminate amount of time, this patch forces a complete re-sync
to occur.

Change-Id: I6913341674dbde5524c2270e824bda4544211eca
---
 handlers/main.yml                | 2 ++
 tasks/repo_post_install.yml      | 1 +
 tasks/repo_pre_install.yml       | 9 +++++++++
 templates/lsyncd.lua.j2          | 2 +-
 templates/repo_prepost_cmd.sh.j2 | 2 ++
 5 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/handlers/main.yml b/handlers/main.yml
index 381a97f..ebfe7a6 100644
--- a/handlers/main.yml
+++ b/handlers/main.yml
@@ -45,3 +45,5 @@
   until: _restart is success
   retries: 5
   delay: 2
+  delegate_to: "{{ groups['repo_all'][0] }}"
+  run_once: true
diff --git a/tasks/repo_post_install.yml b/tasks/repo_post_install.yml
index 7022468..cd0b191 100644
--- a/tasks/repo_post_install.yml
+++ b/tasks/repo_post_install.yml
@@ -53,6 +53,7 @@
       dest: "/etc/nginx/sites-available/openstack-slushee.vhost"
   notify:
     - reload nginx
+    - reload lsyncd
 
 - name: Drop rsyncd configuration file
   template:
diff --git a/tasks/repo_pre_install.yml b/tasks/repo_pre_install.yml
index c1222a6..15fdefa 100644
--- a/tasks/repo_pre_install.yml
+++ b/tasks/repo_pre_install.yml
@@ -50,6 +50,15 @@
     - path: "/var/log/nginx"
       mode: "0775"
 
+- name: Sync file for master repo node
+  file:
+    path: "{{ repo_service_home_folder }}/repo/repo_sync_complete"
+    state: "touch"
+    owner: "{{ repo_service_user_name }}"
+    group: "{{ repo_service_group_name }}"
+  when: inventory_hostname == groups['repo_all'][0]
+  changed_when: False
+
 - name: Drop repo pre/post command script
   template:
     src: repo_prepost_cmd.sh.j2
diff --git a/templates/lsyncd.lua.j2 b/templates/lsyncd.lua.j2
index 5e580b4..032c1d6 100644
--- a/templates/lsyncd.lua.j2
+++ b/templates/lsyncd.lua.j2
@@ -618,7 +618,7 @@ sync {
     rsync,
     source = "{{ repo_service_home_folder }}/repo",
     target = "{{ hostvars[node]['ansible_host'] }}:{{ repo_service_home_folder }}/repo",
-    exclude = "{{ repo_build_global_links_dirname }}",
+    exclude = {"{{ repo_build_global_links_dirname }}","/repo_sync_complete"},
     rsync = {
         compress = true,
         acls = true,
diff --git a/templates/repo_prepost_cmd.sh.j2 b/templates/repo_prepost_cmd.sh.j2
index 2b49ce7..9a1a69f 100644
--- a/templates/repo_prepost_cmd.sh.j2
+++ b/templates/repo_prepost_cmd.sh.j2
@@ -6,10 +6,12 @@ case $CMD in
 pre-www)
   rm /etc/nginx/sites-enabled/openstack-slushee.vhost
   systemctl reload nginx
+  rm -f {{ repo_service_home_folder }}/repo/repo_sync_complete
   ;;
 post-www)
   ln -s /etc/nginx/sites-available/openstack-slushee.vhost /etc/nginx/sites-enabled/openstack-slushee.vhost
   systemctl reload nginx
+  touch {{ repo_service_home_folder }}/repo/repo_sync_complete
   ;;
 *)
   echo "Unknown command."