db: refs #8140 - add new script to change server rol

roles/db/files/scripts/role-change.sh

@@ -0,0 +1,123 @@
+#!/bin/bash
+# Script to manage MariaDB events during replication role changes.
+#
+# Author: Xavi Lleó & GhatGPT ®
+# Copyright (c) 2025 Verdnatura S.L. All rights reserved.
+# Version: 1.4.0
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+# Description:
+# This script toggles MariaDB events during replication role changes.
+# It supports three modes:
+#   --promote : Re-enable events previously marked SLAVESIDE_DISABLED
+#   --demote  : Disable currently ENABLED events using DISABLE ON SLAVE
+#   --status  : Display current status of all events
+# All actions are logged to /var/log/mariadb_admin.log.
+
+set -euo pipefail
+
+LOG_FILE="/var/log/mariadb_admin.log"
+TIMESTAMP="$(date '+%F %T')"
+
+log() {
+    echo "$TIMESTAMP - $1" | tee -a "$LOG_FILE"
+}
+
+disable_scheduler() {
+    log "Disabling event_scheduler..."
+    if mysql -e "SET GLOBAL event_scheduler = OFF"; then
+        log "Successfully disabled event_scheduler"
+    else
+        log "ERROR: Failed to disable event_scheduler"
+        exit 1
+    fi
+}
+
+enable_scheduler() {
+    log "Re-enabling event_scheduler..."
+    if mysql -e "SET GLOBAL event_scheduler = ON"; then
+        log "Successfully re-enabled event_scheduler"
+    else
+        log "ERROR: Failed to re-enable event_scheduler"
+        exit 1
+    fi
+}
+
+final_status() {
+    log "Final event_scheduler status:"
+    mysql --table -e "SHOW VARIABLES LIKE 'event_scheduler';" | tee -a "$LOG_FILE"
+
+    log "Final state of all events:"
+    mysql --table -e "SELECT db, name, status FROM mysql.event;" | tee -a "$LOG_FILE"
+}
+
+if [[ $# -ne 1 ]]; then
+    echo "Usage: $0 --promote | --demote | --status"
+    exit 1
+fi
+
+MODE="$1"
+
+case "$MODE" in
+    --status)
+        log "Fetching current event_scheduler status:"
+        mysql --table -e "SHOW VARIABLES LIKE 'event_scheduler';" | tee -a "$LOG_FILE"
+
+        log "Fetching current event status:"
+        mysql --table -e "SELECT db, name, status FROM mysql.event;" | tee -a "$LOG_FILE"
+        ;;
+    
+    --promote)
+        disable_scheduler
+
+        log "Promoting: Enabling events with SLAVESIDE_DISABLED status..."
+        mysql --raw --silent -e "SELECT db, name FROM mysql.event WHERE status = 'SLAVESIDE_DISABLED'" | \
+        awk '{ gsub("`", "``", $1); gsub("`", "``", $2); print "`"$1"`.`"$2"`" }' | \
+        while read -r event; do
+            if mysql -e "ALTER EVENT $event ENABLE"; then
+                log "Enabled event: $event"
+            else
+                log "ERROR: Failed to enable event: $event"
+            fi
+        done
+
+        enable_scheduler
+        final_status
+        ;;
+
+    --demote)
+        disable_scheduler
+
+        log "Demoting: Disabling events currently ENABLED..."
+        mysql --raw --silent -e "SELECT db, name FROM mysql.event WHERE status = 'ENABLED'" | \
+        awk '{ gsub("`", "``", $1); gsub("`", "``", $2); print "`"$1"`.`"$2"`" }' | \
+        while read -r event; do
+            if mysql -e "ALTER EVENT $event DISABLE ON SLAVE"; then
+                log "Disabled event: $event"
+            else
+                log "ERROR: Failed to disable event: $event"
+            fi
+        done
+
+        enable_scheduler
+        final_status
+        ;;
+
+    *)
+        echo "Invalid mode: $MODE"
+        echo "Usage: $0 --promote | --demote | --status"
+        exit 1
+        ;;
+esac