fix: [mariadb] ensure using the ``--host`` method

This comes from the mysql script. And it'll be required as we need this
script for hosts installs.

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

mariadb/hooks/schedule_command-relation-joined

@@ -33,12 +33,11 @@ COMPOSE_LAUNCHER_OPTS=$COMPOSE_LAUNCHER_OPTS
 
 $schedule   root lock $label -D -p 10 -c "\
     docker run --rm \
-        -e MYSQLHOST="${SERVICE_NAME}" \
         --network ${PROJECT_NAME}_default \
         -v \"$LOCAL_DB_PASSFILE\":/root/.my.cnf \
         -v \"$HOST_CHARM_STORE/${CHARM_REL_PATH#${CHARM_STORE}/}/resources/bin/mysql-backup:/usr/sbin/mysql-backup\" \
         -v \"$SERVICE_DATASTORE/var/backups/mysql:/var/backups/mysql\" \
         --entrypoint mysql-backup \
-        \"$DOCKER_BASE_IMAGE\"" 2>&1 | ts '\%F \%T \%Z' >> /var/log/cron/${label}_script.log
+        \"$DOCKER_BASE_IMAGE\" --host \"${SERVICE_IMAGE}\"" 2>&1 | ts '\%F \%T \%Z' >> /var/log/cron/${label}_script.log
 EOF
 chmod +x "$DST"

mariadb/resources/bin/mysql-backup

@@ -1,5 +1,38 @@
 #!/bin/bash
 
+. /etc/shlib
+
+include common
+include pretty
+
+usage="$exname [--host HOST] [DATABASE...]"
+
+
+DBS=()
+host=
+while [ "$1" ]; do
+    case "$1" in
+        "--help"|"-h")
+            print_usage
+            exit 0
+        ;;
+        "--host")
+            host="$2"
+            shift
+        ;;
+        *)
+            DBS+=("$1")
+        ;;
+    esac
+    shift
+done
+
+
+mysql_opts=()
+if [ "$host" ]; then
+    mysql_opts+=(-h "$host")
+fi
+
 m() {
     mysql "${mysql_opts[@]}" -Bs "$@"
 }
@@ -17,13 +50,10 @@ mysql_tables() {
      echo "SHOW TABLES" | m "$db"
 }
 
-mysql_opts=()
-if [ "$MYSQLHOST" ]; then
-    mysql_opts+=(-h "$MYSQLHOST")
-fi
-
 
-DBS=($(mysql_databases)) || exit 1
+if [ "${#DBS[@]}" == 0 ]; then
+    DBS=($(mysql_databases)) || exit 1
+fi
 
 mkdir -p /var/backups/mysql