Monitoring and Auto-Restarting a Web Service in Bash

#!/bin/bash

SERVICE_NAME="apache2" # Change to your web service, e.g., 'nginx', 'httpd'
LOG_FILE="/var/log/${SERVICE_NAME}_monitor.log"
CHECK_INTERVAL=30 # Check every 30 seconds

# Ensure log file directory exists
mkdir -p "$(dirname "$LOG_FILE")"
touch "$LOG_FILE"

echo "$(date): Starting service monitor for $SERVICE_NAME..." >> "$LOG_FILE"

while true; do
    TIMESTAMP=$(date +%Y-%m-%d_%H:%M:%S)

    # Check if the service is active using systemctl
    # systemctl is-active --quiet returns 0 if active, non-zero otherwise
    if systemctl is-active --quiet "$SERVICE_NAME"; then
        echo "$TIMESTAMP: $SERVICE_NAME is active." >> "$LOG_FILE"
    else
        echo "$TIMESTAMP: $SERVICE_NAME is NOT active. Attempting to restart..." >> "$LOG_FILE"
        # Attempt to restart the service
        systemctl restart "$SERVICE_NAME"
        # Give it a moment and check again
        sleep 5
        if systemctl is-active --quiet "$SERVICE_NAME"; then
            echo "$TIMESTAMP: $SERVICE_NAME restarted successfully." >> "$LOG_FILE"
        else
            echo "$TIMESTAMP: ERROR: $SERVICE_NAME failed to restart. Manual intervention required." >> "$LOG_FILE"
        fi
    fi

    sleep "$CHECK_INTERVAL"
done