db-backup.sh

#!/usr/bin/env bash
# Chateando - PostgreSQL backup helper
#
# Creates a compressed pg_dump of the chateando database from the running
# `postgres` service in docker compose and stores it in a host-side directory.
# Old backups beyond CHATEANDO_BACKUP_KEEP days are pruned.
#
# Usage:
#   ./ops/db-backup.sh
#
# Environment overrides:
#   CHATEANDO_BACKUP_DIR     Backup output directory (default: ./backups)
#   CHATEANDO_BACKUP_KEEP    Retain backups newer than N days (default: 14)
#   CHATEANDO_COMPOSE_FILE   Docker compose file (default: docker-compose.yml)
#   CHATEANDO_DB_SERVICE     Compose service name running Postgres (default: postgres)
#   CHATEANDO_DB_NAME        Database name (default: chateando)
#   CHATEANDO_DB_USER        Postgres role (default: chateando)

set -euo pipefail

backup_dir="${CHATEANDO_BACKUP_DIR:-./backups}"
retain_days="${CHATEANDO_BACKUP_KEEP:-14}"
compose_file="${CHATEANDO_COMPOSE_FILE:-docker-compose.yml}"
db_service="${CHATEANDO_DB_SERVICE:-postgres}"
db_name="${CHATEANDO_DB_NAME:-chateando}"
db_user="${CHATEANDO_DB_USER:-chateando}"

mkdir -p "$backup_dir"

timestamp="$(date -u +%Y%m%dT%H%M%SZ)"
target="$backup_dir/chateando_${timestamp}.dump"

echo "[backup] dumping ${db_name} via service '${db_service}' -> ${target}"
docker compose -f "$compose_file" exec -T "$db_service" \
    pg_dump --format=custom --no-owner --no-privileges --username="$db_user" "$db_name" \
    > "$target"

size=$(stat -c%s "$target" 2>/dev/null || wc -c < "$target")
if [[ "$size" -lt 1024 ]]; then
    echo "[backup] ERROR: dump file is suspiciously small (${size} bytes); aborting." >&2
    rm -f "$target"
    exit 1
fi

echo "[backup] wrote ${size} bytes."

echo "[backup] pruning files older than ${retain_days} day(s) from ${backup_dir}."
find "$backup_dir" -maxdepth 1 -name 'chateando_*.dump' -type f -mtime "+${retain_days}" -print -delete || true

echo "[backup] done."