Docker Backup Container

A minimal Alpine-based container to back up directories and databases on a schedule, with notification support via Nextcloud Talk Bot and e-mail.

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🚀 Features

• ✅ File backups (tar.gz)
• ✅ PostgreSQL, MariaDB and MySQL backups (.sql.gz)
• ✅ Cron-based scheduling
• ✅ Initial backup on container start
• ✅ Retention-based cleanup (delete old backups)
• ✅ Talk Bot notifications (HMAC-based)
• ✅ Optional e-mail notifications via SMTP
• ✅ Stale lockfile cleanup (after 1 hour)
• ✅ Unified logging for file + console (timestamped)
• ✅ Custom container/service/stack labeling for notifications

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📦 Environment Variables

📁 General

Variable	Description	Required
FILES_TO_BACKUP	Space-separated list of folders to back up	✅
BACKUP_DIR	Root folder for all backups	✅
LOG_DIR	Log file location	✅
RETENTION_DAYS	Days to keep old backups	✅
CRON_SCHEDULE	Cron format (e.g. 0 * * * *)	✅
STACK_NAME	Logical stack name (for identification)	❌
BACKUP_NAME	Friendly container/service name	❌

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🛢️ Database (optional)

Set DB_TYPE=postgres, mariadb, mysql, or none

PostgreSQL:

Variable	Description
POSTGRES_HOST	Database host
POSTGRES_PORT	Database port (Standard port 5432 is already set)
POSTGRES_USER	Username
POSTGRES_PASSWORD	Password
POSTGRES_DATABASE	DB name
POSTGRES_EXTRA_OPTS	Extra options

MariaDB:

Variable	Description
MARIADB_HOST	Database host
MARIADB_PORT	Database port (Standard port 3306 is already set)
MARIADB_USER	Username
MARIADBYSQL_PASSWORD	Password
MARIADB_DATABASE	DB name
MARIADB_EXTRA_OPTS	Extra options

MySQL:

Variable	Description
MYSQL_HOST	Database host
MYSQL_PORT	Database port (Standard port 3306 is already set)
MYSQL_USER	Username
MYSQL_PASSWORD	Password
MYSQL_DATABASE	DB name
MYSQL_EXTRA_OPTS	Extra options

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💬 Nextcloud Talk Bot (HMAC)

Variable	Description
NC_TALK_NOTIFY=on	Enable Talk Bot notifications
NC_TALK_URL	Nextcloud base URL
NC_TALK_BOT_CHANNEL	Bot ID or room token (from Talk or occ)
NC_TALK_BOT_SECRET	Shared secret (from php occ talk:bot:install)

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📧 Email Notifications (optional)

Variable	Description
EMAIL_NOTIFY=on	Enable e-mail alerts
EMAIL_TO	Recipient
EMAIL_FROM	Sender
SMTP_SERVER	SMTP hostname/IP
SMTP_PORT	Port (default: 587)
SMTP_USER	SMTP user (if auth needed)
SMTP_PASS	SMTP password
SMTP_TLS=on	Enable STARTTLS (default: on)

📦 Uses msmtp (included) for sending mail

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🧪 Example docker-compose.yml

version: '3'

services:
  backup:
    build: .
    environment:
      FILES_TO_BACKUP: "/data"
      BACKUP_DIR: "/backup"
      LOG_DIR: "/log"
      RETENTION_DAYS: 30
      CRON_SCHEDULE: "0 * * * *"

      BACKUP_NAME: "web-backup-db"

      DB_TYPE: "postgres"
      POSTGRES_HOST: "postgres"
      POSTGRES_USER: "backupuser"
      POSTGRES_PASSWORD: "secret"
      POSTGRES_DATABASE: "myapp"

      NC_TALK_NOTIFY: "off"
      NC_TALK_URL: "https://cloud.example.com"
      NC_TALK_BOT_CHANNEL: "abc123"
      NC_TALK_BOT_SECRET: "your_shared_hmac_secret"

      EMAIL_NOTIFY: "off"
      EMAIL_TO: "alerts@example.com"
      EMAIL_FROM: "backup@host.local"
      SMTP_SERVER: "smtp.example.com"
      SMTP_PORT: 587
      SMTP_USER: "smtp-user"
      SMTP_PASS: "smtp-pass"
      SMTP_TLS: "on"

    volumes:
      - ./data:/data
      - ./backup:/backup
      - ./log:/log

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📂 Folder Structure

/backup/
  2025-04/
    files_data_2025-04-30_1400.tar.gz
    postgres_myapp_2025-04-30_1400.sql.gz
/log/
  backup_2025-04-30.log

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🧹 Cleanup

Backups older than RETENTION_DAYS are removed automatically. Log entries show deleted files.

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🩺 Healthcheck (optional)

Add this to your Compose file to track success:

healthcheck:
  test: ["CMD", "/scripts/healthcheck.sh"]
  interval: 5m
  timeout: 10s
  retries: 3
  start_period: 30s

The backup script writes this file only on success

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🧑‍💻 Author

• Michael Kleger
  OneSystems GmbH
  mkleger@onesystems.ch

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📝 License

MIT License – free for commercial and private use.

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Build

Multi Platform Builder

docker buildx create --use --platform=linux/arm64,linux/amd64 --name multi-platform-builder
docker buildx inspect --bootstrap

Build

docker buildx build --platform linux/amd64,linux/arm64 --push --tag onesystems/dockerbackup:v1.0.5 --file Dockerfile .
docker buildx build --platform linux/amd64,linux/arm64 --push --tag onesystems/dockerbackup:v1.0.5 --tag onesystems/dockerbackup:latest --file Dockerfile .