# backhaul-agent

The public, containerized client for [backhaul](https://backhaul.skui.io) — a database-backup
dashboard with proven restore. Run this as a **sidecar on your database's private Docker
network**: it reaches the database internally and pushes dumps home over HTTPS. **No inbound
ports are ever opened** — the agent only makes outbound calls.

## How it works

- Once a minute (in-container cron) the agent **checks in**: it heartbeats, reports the
  databases it can see, delivers any finished dump, and asks what to do.
- The **app owns the schedule**. When a dump is due, the check-in reply says so; the agent
  runs `pg_dump`/`mysqldump`/`mongodump` and **streams the result home chunked** — never
  buffering the whole dump in memory or on disk.
- The agent **self-updates**: the app advertises the current script version and the agent
  swaps its own script atomically (after a compile check). Disable with
  `BACKHAUL_AUTOUPDATE=0`.

Config pulls, data pushes.

## Run it

```bash
docker run -d --name backhaul-agent --restart unless-stopped \
  --network <DB_DOCKER_NETWORK> \
  -e BACKHAUL_URL=https://backhaul.skui.io \
  -e BACKHAUL_TOKEN=<token from the backhaul admin> \
  -e BACKHAUL_TARGETS=postgres:<DB_HOST>:5432:<DB_NAME>:<USER>:<PASS> \
  git.skui.io/steffen/backhaul-agent:latest
```

- `--network` must be the **same private Docker network as the database**, so the agent can
  reach it by service name.
- `BACKHAUL_TARGETS` is a comma-separated list, each entry
  `engine:host:port:db:user:pass`. Engines: `postgres`, `mysql`, `mariadb`, `mongo`.

The agent registers each target with the app on its first check-in; tune the dump cadence,
retention, and restore-drill schedule from the backhaul dashboard.

## What's in the image

Debian slim + Python 3 (stdlib only — the agent has no Python dependencies) +
`postgresql-client-17` (pg_dump 17, required to dump Postgres 17 servers) +
`default-mysql-client`. MongoDB tools are added in a follow-up.

## Logs

```bash
docker logs -f backhaul-agent          # check-in activity
```