Add mysql support for ceilometer storage backend in devstack

Currently, devstack only support mongodb as ceilometer storage backend,
this patch is to add mysql storage support for ceilometer.
If you want to use mysql as backend during developing, you can specify
CEILOMETER_BACKEND=mysql in localrc file.
If you use mongodb, just ignore the parameter.

Change-Id: Ic2f475a9baa6d71a43cd29a6ca777ac972e47b0a
Implements: blueprint ceilometer-mysql-support

lib/ceilometer

@@ -37,12 +37,10 @@ CEILOMETER_API_LOG_DIR=/var/log/ceilometer-api
 CEILOMETER_AUTH_CACHE_DIR=${CEILOMETER_AUTH_CACHE_DIR:-/var/cache/ceilometer}
 
 # Support potential entry-points console scripts
-if [[ -d $CEILOMETER_DIR/bin ]]; then
-    CEILOMETER_BIN_DIR=$CEILOMETER_DIR/bin
-else
 CEILOMETER_BIN_DIR=$(get_python_exec_prefix)
-fi
 
+# Set up database backend
+CEILOMETER_BACKEND=${CEILOMETER_BACKEND:-mongodb}
 
 # Functions
 # ---------
@@ -91,11 +89,13 @@ function configure_ceilometer() {
     iniset $CEILOMETER_CONF keystone_authtoken admin_tenant_name $SERVICE_TENANT_NAME
     iniset $CEILOMETER_CONF keystone_authtoken signing_dir $CEILOMETER_AUTH_CACHE_DIR
 
+    if [[ "$CEILOMETER_BACKEND" = 'mysql' ]]; then
+        iniset $CEILOMETER_CONF database connection `database_connection_url ceilometer`
+    else
         iniset $CEILOMETER_CONF database connection mongodb://localhost:27017/ceilometer
-
         configure_mongodb
-
         cleanup_ceilometer
+    fi
 }
 
 function configure_mongodb() {
@@ -113,6 +113,11 @@ function init_ceilometer() {
     sudo mkdir -p $CEILOMETER_AUTH_CACHE_DIR
     sudo chown $STACK_USER $CEILOMETER_AUTH_CACHE_DIR
     rm -f $CEILOMETER_AUTH_CACHE_DIR/*
+
+    if [[ "$CEILOMETER_BACKEND" = 'mysql' ]]; then
+        recreate_database ceilometer utf8
+        $CEILOMETER_BIN_DIR/ceilometer-dbsync
+    fi
 }
 
 # install_ceilometer() - Collect source and prepare