From eaa1834b972b090b8dc66da906fe4707a4239362 Mon Sep 17 00:00:00 2001
From: Adam Gandelman <adamg@canonical.com>
Date: Thu, 4 Apr 2013 19:34:08 -0400
Subject: [PATCH] Avoid excessive svc restarts by tracking CONFIG_CHANGED.

---
 hooks/glance-common        | 13 ++++++++++---
 hooks/glance-relations     |  2 --
 hooks/lib/openstack-common | 14 +++++++++++++-
 revision                   |  2 +-
 4 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/hooks/glance-common b/hooks/glance-common
index e471cbe4..06e8f362 100755
--- a/hooks/glance-common
+++ b/hooks/glance-common
@@ -11,6 +11,8 @@ GLANCE_API_CONF="/etc/glance/glance-api.conf"
 GLANCE_API_PASTE_INI="/etc/glance/glance-api-paste.ini"
 CONF_DIR="/etc/glance"
 
+# Flag used to track config changes.
+CONFIG_CHANGED="False"
 if [[ -e "$CHARM_DIR/lib/openstack-common" ]] ; then
   . $CHARM_DIR/lib/openstack-common
 else
@@ -18,6 +20,8 @@ else
 fi
 
 function set_paste_deploy_flavor {
+  # NOTE(adam_g): If we want to benefit from CONFIG_CHANGED here,
+  # needs to be updated to detect already config'd settings.
   local flavor="$1"
   local config="$2"
   case $config in
@@ -27,12 +31,14 @@ function set_paste_deploy_flavor {
   esac
   if ! grep -q "\[paste_deploy\]" "$conf" ; then
     juju-log "Updating $conf: Setting new paste_deploy flavor = $flavor"
-    echo -e "\n[paste_deploy]\nflavor = keystone\n" >>$conf && return 0
+    echo -e "\n[paste_deploy]\nflavor = keystone\n" >>$conf &&
+      CONFIG_CHANGED="True" && return 0
     juju-log "ERROR: Could not update paste_deploy flavor in $conf" && return 1
   fi
   juju-log "Updating $conf: Setting paste_deploy flavor = $flavor"
   local tag="[paste_deploy]"
-  sed -i "/$tag/, +1 s/\(flavor = \).*/\1$flavor/g" $conf && return 0
+  sed -i "/$tag/, +1 s/\(flavor = \).*/\1$flavor/g" $conf &&
+    CONFIG_CHANGED="True" && return 0
   juju-log "ERROR: Could not update paste_deploy flavor in $conf" && return 1
 }
 
@@ -77,12 +83,13 @@ function set_or_update {
   [[ -z $VALUE ]] && juju-log "ERROR: set_or_update(): key $KEY missing value" \
         && exit 1
   cat $CONF | grep "$KEY = $VALUE" >/dev/null \
-   && juju-log "glance: $KEY = $VALUE already set" exit 0
+   && juju-log "glance: $KEY = $VALUE already set" && return 0
   if cat $CONF | grep "$KEY =" >/dev/null ; then
     sed -i "s|\($KEY = \).*|\1$VALUE|" $CONF
   else
     echo "$KEY = $VALUE" >>$CONF
   fi
+  CONFIG_CHANGED="True"
 }
 
 do_openstack_upgrade() {
diff --git a/hooks/glance-relations b/hooks/glance-relations
index 6175fde0..4667ff5b 100755
--- a/hooks/glance-relations
+++ b/hooks/glance-relations
@@ -71,8 +71,6 @@ function db_changed {
 
   juju-log "$CHARM - db_changed: Configuring glance.conf for access to $glance_db"
 
-  service_ctl all stop
-
   set_or_update sql_connection "mysql://$db_user:$db_password@$db_host/$glance_db" registry
 
   # since folsom, a db connection setting in glance-api.conf is required.
diff --git a/hooks/lib/openstack-common b/hooks/lib/openstack-common
index a3ecfc1f..77ce75e7 100644
--- a/hooks/lib/openstack-common
+++ b/hooks/lib/openstack-common
@@ -20,6 +20,9 @@ function service_ctl_status {
 
 function service_ctl {
   # control a specific service, or all (as defined by $SERVICES)
+  # service restarts will only occur depending on global $CONFIG_CHANGED,
+  # which should be updated in charm's set_or_update().
+  local config_changed=${CONFIG_CHANGED:-True}
   if [[ $1 == "all" ]] ; then
     ctl="$SERVICES"
   else
@@ -37,12 +40,21 @@ function service_ctl {
       "stop")
         service_ctl_status $i && service $i stop || return 0 ;;
       "restart")
-        service_ctl_status $i && service $i restart || service $i start ;;
+        if [[ "$config_changed" == "True" ]] ; then
+          service_ctl_status $i && service $i restart || service $i start
+        fi
+        ;;
     esac
     if [[ $? != 0 ]] ; then
       juju-log "$CHARM: service_ctl ERROR - Service $i failed to $action"
     fi
   done
+  # all configs should have been reloaded on restart of all services, reset
+  # flag if its being used.
+  if [[ "$action" == "restart" ]] && [[ -n "$CONFIG_CHANGED" ]] &&
+     [[ "$ctl" == "all" ]]; then
+    CONFIG_CHANGED="False"
+  fi
 }
 
 function configure_install_source {
diff --git a/revision b/revision
index 94361d49..dee261df 100644
--- a/revision
+++ b/revision
@@ -1 +1 @@
-132
+140