FTP incremental backup

#!/bin/bash

# ========== CONFIGURATION ==========
FTP_HOST="serverIP"
FTP_USER="FTPuser"
FTP_PASS="password"

# Local backup paths
BASE_BACKUP_DIR="/volume/BackupServer/GameServer_Backup"
STORAGE_BACKUP_DIR="$BASE_BACKUP_DIR/storage"
VIRTUAL_BACKUP_DIR="$BASE_BACKUP_DIR/virtual"
LOG_DIR="$BASE_BACKUP_DIR/logs"

# Max backup versions to keep
MAX_ROTATIONS=120

# Timestamp
NOW=$(date +"%Y-%m-%d_%H-%M")

# Log file
mkdir -p "$LOG_DIR"
LOGFILE="$LOG_DIR/backup_$NOW.log"

# Lockfile to prevent concurrent execution
LOCKFILE="$BASE_BACKUP_DIR/backup_script.lock"

# ========== PREVENT MULTIPLE INSTANCES ==========
if [ -e "$LOCKFILE" ]; then
    echo "[$(date +"%Y-%m-%d %H:%M:%S")] ERROR: Script is already running." | tee -a "$LOGFILE"
    exit 1
fi

touch "$LOCKFILE"
trap 'rm -f "$LOCKFILE"; exit' INT TERM EXIT

# ========== FUNCTIONS ==========

rotate_backups() {
    local dir=$1
    cd "$dir" || exit 1
    local backups=( $(ls -1d 20* 2>/dev/null | sort) )
    local count=${#backups[@]}

    if (( count >= MAX_ROTATIONS )); then
        local to_delete=$((count - MAX_ROTATIONS + 1))
        for ((i=0; i<to_delete; i++)); do
            echo "Deleting old backup: ${backups[$i]}" | tee -a "$LOGFILE"
            rm -rf "${backups[$i]}"
        done
    fi
}

cleanup_old_logs() {
    echo "[*] Cleaning up log files older than 15 days..." | tee -a "$LOGFILE"
    find "$LOG_DIR" -type f -name "backup_*.log" -mtime +15 -exec rm -f {} \;
}

backup_storage() {
    echo "[*] Backing up /storage/backup/011" | tee -a "$LOGFILE"
    local dest_dir="$STORAGE_BACKUP_DIR/$NOW"
    mkdir -p "$dest_dir"

    timeout 7200 lftp -u "$FTP_USER","$FTP_PASS" "$FTP_HOST" <<EOF 2>&1 | tee -a "$LOGFILE"
set ftp:passive-mode true
set net:timeout 300
set net:max-retries 2
mirror --verbose /ftpServer/main/folder/to/storage/011 "$dest_dir/011"
quit
EOF

    rotate_backups "$STORAGE_BACKUP_DIR"
}

backup_virtual_incremental() {
    echo "[*] Backing up /storage/virtual (incremental)" | tee -a "$LOGFILE"
    local dest_dir="$VIRTUAL_BACKUP_DIR/$NOW"
    mkdir -p "$dest_dir"

    # === STEP 1: Copy entire content from previous backup before download ===
    local last_backup=$(ls -1d "$VIRTUAL_BACKUP_DIR"/20* 2>/dev/null | sort | tail -n 1)
    if [ -d "$last_backup" ]; then
        echo "[*] Copying previous backup from $last_backup to $dest_dir..." | tee -a "$LOGFILE"

        # Copy folder structure first
        rsync -a --include='*/' --exclude='*' "$last_backup/" "$dest_dir/" | tee -a "$LOGFILE"

        # Then copy files that don't exist yet
        rsync -a --ignore-existing "$last_backup/" "$dest_dir/" | tee -a "$LOGFILE"

        echo "[*] Copy from previous backup complete." | tee -a "$LOGFILE"
    else
        echo "[!] No previous backup found. Starting fresh." | tee -a "$LOGFILE"
    fi

    # === STEP 2: FTP mirror with only-newer logic ===
    echo "[*] Downloading updated and new files from FTP..." | tee -a "$LOGFILE"
    local lftp_log="/tmp/lftp_virtual_$$.log"
    > "$lftp_log"

    timeout 7200 lftp -u "$FTP_USER","$FTP_PASS" "$FTP_HOST" <<EOF > "$lftp_log" 2>&1
set ftp:passive-mode true
set net:timeout 300
set net:max-retries 2
mirror --only-newer --parallel=4 /ftpServer/main/folder/to/storage/virtual "$dest_dir"
quit
EOF

    local changed_files_count
    changed_files_count=$(grep -E '^Transferring|^=>|^<=|^Removing' "$lftp_log" | wc -l)
    echo "[*] FTP sync complete. Files changed or added: $changed_files_count" | tee -a "$LOGFILE"
    cat "$lftp_log" >> "$LOGFILE"
    rm -f "$lftp_log"

    rotate_backups "$VIRTUAL_BACKUP_DIR"
}

# ========== MAIN ==========
echo "===== Backup started at $NOW =====" | tee -a "$LOGFILE"

mkdir -p "$STORAGE_BACKUP_DIR"
mkdir -p "$VIRTUAL_BACKUP_DIR"

backup_storage
backup_virtual_incremental
cleanup_old_logs

echo "===== Backup finished at $(date +"%Y-%m-%d %H:%M:%S") =====" | tee -a "$LOGFILE"

# Cleanup
rm -f "$LOCKFILE"
trap - INT TERM EXIT