This repository provides a Docker-based tool for automatically discovering and backing up databases running in Docker containers. The core logic resides in a single Python script (`db-auto-backup.py`) that uses the Docker SDK to list running containers, identifies database containers by image name (PostgreSQL, MySQL/MariaDB, Redis), and executes native backup commands (pg_dumpall, mysqldump, redis-cli SAVE). Backups are written to a configurable directory with optional compression (gzip, lzma, bz2, zstd) and can be scheduled via cron expressions using the pycron library. The tool also supports success hooks (e.g., healthchecks.io, Uptime Kuma) and environment variable configuration. It is designed to run as a standalone Docker container with access to the Docker socket, making it a lightweight, self-contained backup solution for Docker hosts. The codebase is well-structured with type hints, linting, and a comprehensive test suite that validates backup generation and compression across multiple database types.