ejabberdctl: New "mnesia_change" command, a frontend to mnesia_change_nodename

ejabberdctl.template

@@ -318,6 +318,13 @@ check_start()
 # allow sync calls
 wait_status()
 {
+    wait_status_node "$ERLANG_NODE" $1 $2 $3
+}
+
+wait_status_node()
+{
+    CONNECT_NODE=$1
+    shift
     # args: status try delay
     # return: 0 OK, 1 KO
     timeout="$2"
@@ -329,9 +336,9 @@ wait_status()
             status="$1"
         else
             exec_erl "$(uid ctl)" -hidden -noinput \
-                     -eval 'net_kernel:connect_node('"'$ERLANG_NODE'"')' \
+                     -eval 'net_kernel:connect_node('"'$CONNECT_NODE'"')' \
                      -s ejabberd_ctl \
-                     -extra "$ERLANG_NODE" $NO_TIMEOUT status > /dev/null
+                     -extra "$CONNECT_NODE" $NO_TIMEOUT status > /dev/null
             status="$?"
         fi
     done
@@ -340,19 +347,26 @@ wait_status()
 
 exec_other_command()
 {
+    exec_other_command_node $ERLANG_NODE "$@"
+}
+
+exec_other_command_node()
+{
+    CONNECT_NODE=$1
+    shift
     if [ -z "$CTL_OVER_HTTP" ] || [ ! -S "$CTL_OVER_HTTP" ] \
         || [ ! -x "$(command -v curl)" ] || [ -z "$1" ] || [ "$1" = "help" ] \
         || [ "$1" = "mnesia_info_ctl" ]|| [ "$1" = "print_sql_schema" ] ; then
         exec_erl "$(uid ctl)" -hidden -noinput \
-                 -eval 'net_kernel:connect_node('"'$ERLANG_NODE'"')' \
+                 -eval 'net_kernel:connect_node('"'$CONNECT_NODE'"')' \
                  -s ejabberd_ctl \
-                 -extra "$ERLANG_NODE" $NO_TIMEOUT "$@"
+                 -extra "$CONNECT_NODE" $NO_TIMEOUT "$@"
         result=$?
         case $result in
             3) help;;
             *) :;;
         esac
-        exit $result
+        return $result
     else
         exec_ctl_over_http_socket "$@"
     fi
@@ -393,6 +407,103 @@ cd "$SPOOL_DIR" || {
     exit 6
 }
 
+printe()
+{
+    printf "\n"
+    printf "\e[1;40;32m==> %s\e[0m\n" "$1"
+}
+
+## Function copied from tools/make-installers
+user_agrees()
+{
+    question="$*"
+
+    if [ -t 0 ]
+    then
+        printe "$question (y/n) [n]"
+        read -r response
+        case "$response" in
+        [Yy]|[Yy][Ee][Ss])
+            return 0
+            ;;
+        [Nn]|[Nn][Oo]|'')
+            return 1
+            ;;
+        *)
+            echo 'Please respond with "yes" or "no".'
+            user_agrees "$question"
+            ;;
+        esac
+    else # Assume 'yes' if not running interactively.
+        return 0
+    fi
+}
+
+mnesia_change()
+{
+    ERLANG_NODE_OLD="$1"
+    [ "$ERLANG_NODE_OLD" = "" ] \
+        && echo "Error: Please provide the old erlang node name, for example:" \
+        && echo "  ejabberdctl mnesia_change ejabberd@oldmachine" \
+        && exit 1
+
+    SPOOL_DIR_BACKUP=$SPOOL_DIR/$ERLANG_NODE_OLD-backup/
+    OLDFILE=$SPOOL_DIR_BACKUP/$ERLANG_NODE_OLD.backup
+    NEWFILE=$SPOOL_DIR_BACKUP/$ERLANG_NODE.backup
+
+    printe "This changes your mnesia database from node name '$ERLANG_NODE_OLD' to '$ERLANG_NODE'"
+
+    [ -d "$SPOOL_DIR_BACKUP" ] && printe "WARNING! A backup of old node already exists in $SPOOL_DIR_BACKUP"
+
+    if ! user_agrees "Do you want to proceed?"
+    then
+        echo 'Operation aborted.'
+        exit 1
+    fi
+
+    printe "Starting ejabberd with old node name $ERLANG_NODE_OLD ..."
+    exec_erl "$ERLANG_NODE_OLD" $EJABBERD_OPTS -detached
+    wait_status_node $ERLANG_NODE_OLD 0 30 2
+    result=$?
+    case $result in
+        1) echo "There was a problem starting ejabberd with the old erlang node name. " \
+            && echo "Check for log errors in $EJABBERD_LOG_PATH" \
+            && exit $result;;
+        *) :;;
+    esac
+    exec_other_command_node $ERLANG_NODE_OLD "status"
+
+    printe "Making backup of old database to file $OLDFILE ..."
+    mkdir $SPOOL_DIR_BACKUP
+    exec_other_command_node $ERLANG_NODE_OLD backup "$OLDFILE"
+
+    printe "Changing node name in new backup file $NEWFILE ..."
+    exec_other_command_node $ERLANG_NODE_OLD mnesia_change_nodename "$ERLANG_NODE_OLD" "$ERLANG_NODE" "$OLDFILE" "$NEWFILE"
+
+    printe "Stopping old ejabberd..."
+    exec_other_command_node $ERLANG_NODE_OLD "stop"
+    wait_status_node $ERLANG_NODE_OLD 3 30 2 && stop_epmd
+
+    printe "Moving old mnesia spool files to backup subdirectory $SPOOL_DIR_BACKUP ..."
+    mv $SPOOL_DIR/*.DAT $SPOOL_DIR_BACKUP
+    mv $SPOOL_DIR/*.DCD $SPOOL_DIR_BACKUP
+    mv $SPOOL_DIR/*.LOG $SPOOL_DIR_BACKUP
+
+    printe "Starting ejabberd with new node name $ERLANG_NODE ..."
+    exec_erl "$ERLANG_NODE" $EJABBERD_OPTS -detached
+    wait_status 0 30 2
+    exec_other_command "status"
+
+    printe "Installing fallback of new mnesia..."
+    exec_other_command install_fallback "$NEWFILE"
+
+    printe "Stopping new ejabberd..."
+    exec_other_command "stop"
+    wait_status 3 30 2 && stop_epmd
+
+    printe "Finished, now you can start ejabberd normally"
+}
+
 # main
 case $1 in
     start)
@@ -452,6 +563,9 @@ case $1 in
         set_dist_client
         wait_status 3 30 2 && stop_epmd # wait 30x2s before timeout
         ;;
+    mnesia_change)
+        mnesia_change $2
+        ;;
     *)
         set_dist_client
         exec_other_command "$@"

src/ejabberd_ctl.erl

@@ -1148,6 +1148,17 @@ get_commands_spec() ->
 			desc = "Get list of commands, or help of a command (only ejabberdctl)",
 			longdesc = "This command is exclusive for the ejabberdctl command-line script, "
 			"don't attempt to execute it using any other API frontend."},
+     #ejabberd_commands{name = mnesia_change, tags = [ejabberdctl, mnesia],
+			desc = "Change the erlang node name in the mnesia database (only ejabberdctl)",
+			longdesc = "This command internally calls the _`mnesia_change_nodename`_ API. "
+			"This is a special command that starts and stops ejabberd several times: "
+			"do not attempt to run this command when ejabberd is running. "
+			"This command is exclusive for the ejabberdctl command-line script, "
+			"don't attempt to execute it using any other API frontend.",
+			note = "added in 25.xx",
+			args = [{old_node_name, string}],
+			args_desc = ["Old erlang node name"],
+			args_example = ["ejabberd@oldmachine"]},
      #ejabberd_commands{name = mnesia_info_ctl, tags = [ejabberdctl, mnesia],
 			desc = "Show information of Mnesia system (only ejabberdctl)",
 			note = "renamed in 24.02",

src/ejabberd_mnesia.erl

@@ -80,10 +80,11 @@ init([]) ->
 	    Schema = read_schema_file(),
 	    {ok, #state{schema = Schema}};
 	false ->
-	    ?CRITICAL_MSG("Node name mismatch: I'm [~ts], "
-			  "the database is owned by ~p", [MyNode, DbNodes]),
+	    ?CRITICAL_MSG("Erlang node name mismatch: I'm running in node [~ts], "
+			  "but the mnesia database is owned by ~p", [MyNode, DbNodes]),
 	    ?CRITICAL_MSG("Either set ERLANG_NODE in ejabberdctl.cfg "
-			  "or change node name in Mnesia", []),
+			  "or change node name in Mnesia by running: "
+			  "ejabberdctl mnesia_change ~ts", [hd(DbNodes)]),
 	    {stop, node_name_mismatch}
     end.