fix: [mongo] exit script on failure of some sub command

mongo/hooks/mongo_database-relation-joined

@@ -39,6 +39,8 @@ if version_gt "$version" 4.1; then
 
 fi
 
+## This is some sort of migrating code and should be moved to upgrade
+## directory.
 
 if dbs=$(mongo:db:ls); then
     if matching_db=$(e "$dbs" | egrep "[a-zA-Z0-9.-_]*_${DBNAME}"); then
@@ -47,15 +49,25 @@ if dbs=$(mongo:db:ls); then
                 "found along with database named '${DBNAME}'."
             exit 1
         fi
+
+        ## XXXvlab: there's probably an unsolved issue here when
+        ## =ensure_db_docker_running= returned the current running
+        ## service container, that we are about to stop in the
+        ## following lines. I'm not digging much into that because
+        ## this code is probably not concerning any current live
+        ## deployment anymore: this was written for an evolution of
+        ## the charm a long time ago, and probably should be deleted
+        ## now.
+
         ## Let's take for granted that only current source service is
         ## concerned by the database. We need to restart source service
         ## container only if already running.
         container_ids=($(get_running_containers_for_service "$MASTER_BASE_SERVICE_NAME"))
         for container_id in "${container_ids[@]}"; do
-            mongo_url=$(docker:container:env_get "$container_id" MONGO_URL) || return 1
+            mongo_url=$(docker:container:env_get "$container_id" MONGO_URL) || exit 1
             if [[ "$mongo_url" == */"${matching_db}"* ]]; then
                 info "Attempting to stop current containers of service $MASTER_BASE_SERVICE_NAME"
-                docker stop -t 5 "$container_id"
+                docker stop -t 5 "$container_id" || exit 1
             fi
         done