Enable HAProxy consider MariaDB wsrep_local_state

This patch enable wsrep_notify_cmd to rename haproxy user in haproxy_blocked
when the node is not ready to serve and restore it when ready.

Change-Id: I4f49960d7ff2fa689d6ea730b2574f16f083edc1
Closes-Bug: 1578752
Closes-Bug: 1587752

ansible/roles/mariadb/tasks/config.yml

@@ -25,3 +25,10 @@
     dest: "{{ node_config_directory }}/{{ item }}/galera.cnf"
   with_items:
     - "mariadb"
+
+- name: Copying over wsrep_notify.sh
+  template:
+    src: "{{ role_path }}/templates/wsrep_notify.sh.j2"
+    dest: "{{ node_config_directory }}/{{ item }}/wsrep_notify.sh"
+  with_items:
+    - "mariadb"

ansible/roles/mariadb/templates/galera.cnf.j2

@@ -24,6 +24,7 @@ wsrep_node_name={{ ansible_hostname }}
 wsrep_sst_method=xtrabackup-v2
 wsrep_sst_auth={{ database_user }}:{{ database_password }}
 wsrep_slave_threads=4
+wsrep_notify_cmd=/usr/local/bin/wsrep_notify.sh
 
 max_connections=10000
 

ansible/roles/mariadb/templates/mariadb.json.j2

@@ -7,6 +7,12 @@
             "dest": "/etc/{{ mysql_dir }}/my.cnf",
             "owner": "mysql",
             "perm": "0600"
+        },
+        {
+            "source": "{{ container_config_directory }}/wsrep_notify.sh",
+            "dest": "/usr/local/bin/wsrep_notify.sh",
+            "owner": "mysql",
+            "perm": "0700"
         }
     ]
 }

ansible/roles/mariadb/templates/wsrep_notify.sh.j2

@@ -0,0 +1,75 @@
+#!/bin/bash -e
+
+# Edit parameters below to specify the address and login to server.
+USER={{ database_user }}
+PSWD={{ database_password }}
+HOST={{ hostvars[inventory_hostname]['ansible_' + api_interface]['ipv4']['address'] }}
+PORT={{ mariadb_port }}
+LB_USER=haproxy
+
+ENABLE_LB="UPDATE mysql.user SET User='${LB_USER}' WHERE User='${LB_USER}_blocked';"
+DISABLE_LB="UPDATE mysql.user SET User='${LB_USER}_blocked' WHERE User='${LB_USER}';"
+MYSQL_CMD="`type -p mysql` -B -u$USER -p$PSWD -h$HOST -P$PORT"
+
+status_update()
+{
+    echo "SET SESSION wsrep_on=off;"
+    echo "$@"
+    echo "FLUSH PRIVILEGES;"
+}
+
+get_sst_method()
+{
+    $MYSQL_CMD -s -N -e "SHOW VARIABLES LIKE 'wsrep_sst_method';" | awk '{ print $2 }'
+}
+
+while [ $# -gt 0 ]
+do
+    case $1 in
+    --status)
+        STATUS=$2
+        shift
+        ;;
+    --uuid)
+        CLUSTER_UUID=$2
+        shift
+        ;;
+    --primary)
+        [ "$2" = "yes" ] && PRIMARY="1" || PRIMARY="0"
+        shift
+        ;;
+    --index)
+        INDEX=$2
+        shift
+        ;;
+    --members)
+        MEMBERS=$2
+        shift
+        ;;
+    esac
+    shift
+done
+
+case $STATUS in
+Synced)
+    CMD=$ENABLE_LB
+    ;;
+Donor)
+    # enabling donor only if xtrabackup configured
+    SST_METHOD=`get_sst_method`
+    [[ $SST_METHOD =~ 'xtrabackup' ]] && CMD=$ENABLE_LB || CMD=$DISABLE_LB
+    ;;
+Undefined)
+    # shutting down database: do nothing
+    ;;
+*)
+    CMD=$DISABLE_LB
+    ;;
+esac
+
+if [ -n "$CMD" ]
+then
+    status_update "$CMD" | $MYSQL_CMD
+fi
+
+exit 0