# docker-compose-backup

A backup tool for Docker Compose projects with **minimal downtime** — stop, copy, restart (seconds), then compress after the service is back online.

## How It Works

1. `docker compose stop` — stops the containers
2. `copy` — copies the entire project directory to a staging area
3. `docker compose up -d` — restarts containers immediately (downtime ends here)
4. `tar.gz` — compresses the snapshot into the backup directory after restart
5. Optional: upload to S3 / WebDAV
6. Retention: auto-deletes old backups per policy

## Installation

### Download a pre-built binary (recommended)

Download the latest release for your architecture:

```bash
# linux amd64
curl -fsSL -o docker-compose-backup https://git.misaka.ren/m1saka/docker-compose-backup/releases/download/latest/docker-compose-backup-linux-amd64
# linux arm64
curl -fsSL -o docker-compose-backup https://git.misaka.ren/m1saka/docker-compose-backup/releases/download/latest/docker-compose-backup-linux-arm64

chmod +x docker-compose-backup
```

### Build from source

```bash
go build -o docker-compose-backup .
# or cross-compile:
GOOS=linux GOARCH=arm64 go build -o docker-compose-backup-linux-arm64 .
```

## Quick Start

1. Copy and edit the config:

```bash
cp config.example.yaml config.yaml
```

2. Run a backup:

```bash
./docker-compose-backup backup -c config.yaml
```

3. List configured projects and existing backups:

```bash
./docker-compose-backup list -c config.yaml
```

4. Run as a daemon with cron scheduling:

```bash
./docker-compose-backup daemon -c config.yaml
```

## systemd deployment

This repository includes `docker-compose-backup.service`, configured for installation under `/opt/docker-compose-backup`:

```bash
sudo mkdir -p /opt/docker-compose-backup
# Download the latest release (pick amd64 or arm64 to match the host):
sudo curl -fsSL -o /opt/docker-compose-backup/docker-compose-backup \
  https://git.misaka.ren/m1saka/docker-compose-backup/releases/download/latest/docker-compose-backup-linux-arm64
sudo chmod +x /opt/docker-compose-backup/docker-compose-backup
sudo cp config.yaml /opt/docker-compose-backup/config.yaml
sudo mkdir -p /opt/docker-compose-backup/backups /opt/docker-compose-backup/tmp
sudo cp docker-compose-backup.service /opt/docker-compose-backup/docker-compose-backup.service
sudo ln -sf /opt/docker-compose-backup/docker-compose-backup.service /etc/systemd/system/docker-compose-backup.service
sudo systemctl daemon-reload
sudo systemctl enable --now docker-compose-backup
```

The example config uses `/opt/docker-compose-backup/backups`, which is allowed by the service sandbox. The unit's `ReadWritePaths` covers the whole install dir, so set `global.temp_dir` to a subdirectory there (e.g. `/opt/docker-compose-backup/tmp`). The unit intentionally does **not** enable `PrivateTmp`, since a private `/tmp` is often small and would be exhausted when copying large project directories.

## Configuration

See [config.example.yaml](config.example.yaml) for a full annotated example.

```yaml
global:
  backup_dir: /opt/docker-compose-backup/backups
  temp_dir: /opt/docker-compose-backup/tmp  # optional, defaults to OS temp

projects:
  - name: myapp
    path: /opt/docker/myapp
    compose_file: docker-compose.yml  # default
    cron: "0 3 * * *"                # optional: daily at 3 AM, standard 5-field cron
    exclude:
      - ".git"
      - "node_modules"
    retention:
      count: 7                       # keep last 7 backups
      days: 30                       # optional: also delete >30 days

# Optional: remote upload
# remote:
#   s3:
#     endpoint: https://s3.example.com
#     bucket: my-backups
#     access_key: ${S3_ACCESS_KEY}
#     secret_key: ${S3_SECRET_KEY}
#     region: us-east-1
#     path_prefix: docker-backups/
#   webdav:
#     url: https://webdav.example.com/backups
#     username: user
#     password: ${WEBDAV_PASSWORD}
```

Environment variables in `${VAR}` form are expanded automatically.

## License

MIT. See [LICENSE](LICENSE).

`exclude` uses Go `filepath.Match` patterns and also matches each file/directory basename. It is **not** full `.gitignore` syntax: `**` and negation rules like `!foo` are not supported.

## Commands

| Command    | Description                                           |
|------------|-------------------------------------------------------|
| `backup`   | Run backup for all projects, print summary            |
| `list`     | List configured projects and their existing backups   |
| `daemon`   | Run as a background daemon with cron scheduling       |

Global flags:

| Flag            | Description                    |
|-----------------|--------------------------------|
| `-c, --config`  | Path to config file (default: `config.yaml`) |
| `--dry-run`     | Print actions without executing              |
| `--version`     | Print version                                |

## Requirements

- Docker CLI accessible on `PATH`
- Go 1.26+ (to build from source)