banger/README.md

# banger

`banger` manages Firecracker development VMs with a local daemon, managed image artifacts, and a localhost web UI.

## Requirements

- Linux with `/dev/kvm`
- `sudo`
- Firecracker installed on `PATH`, or `firecracker_bin` set in config
- The usual host tools checked by `./build/bin/banger doctor`

`banger` now owns complete managed image sets. A managed image includes:

- `rootfs`
- optional `work-seed`
- `kernel`
- optional `initrd`
- optional `modules`

There is no runtime bundle anymore.

## Build

```bash
make build
```

This writes:

- `./build/bin/banger`
- `./build/bin/bangerd`
- `./build/bin/banger-vsock-agent`

## Install

```bash
make install
```

That installs:

- `banger`
- `bangerd`
- the `banger-vsock-agent` companion helper under `../lib/banger/`

## Config

Config lives at `~/.config/banger/config.toml`.

Supported keys:

- `log_level`
- `web_listen_addr`
- `firecracker_bin`
- `ssh_key_path`
- `default_image_name`
- `auto_stop_stale_after`
- `stats_poll_interval`
- `metrics_poll_interval`
- `bridge_name`
- `bridge_ip`
- `cidr`
- `tap_pool_size`
- `default_dns`

If `ssh_key_path` is unset, banger creates and uses:

- `~/.config/banger/ssh/id_ed25519`

`default_image_name` now only means “use this registered image when `vm create` omits `--image`”. The daemon does not auto-register images from host paths.

## Core Workflow

Check the host:

```bash
./build/bin/banger doctor
```

Register an existing host-side image stack:

```bash
./build/bin/banger image register \
  --name base \
  --rootfs /abs/path/rootfs.ext4 \
  --kernel /abs/path/vmlinux \
  --initrd /abs/path/initrd.img \
  --modules /abs/path/modules
```

Build a managed image from an existing registered image:

```bash
./build/bin/banger image build \
  --name devbox \
  --from-image base \
  --docker
```

Promote an unmanaged image into daemon-owned managed artifacts:

```bash
./build/bin/banger image promote base
```

Create and use a VM:

```bash
./build/bin/banger vm create --image devbox --name testbox
./build/bin/banger vm ssh testbox
./build/bin/banger vm stop testbox
```

`vm create` stays synchronous by default, but on a TTY it now shows live progress until the VM is fully ready.

Start a repo-backed VM session and attach `opencode` automatically:

```bash
./build/bin/banger vm run
./build/bin/banger vm run ../some-repo --branch feature/alpine --from HEAD
```

`vm run` resolves the enclosing git repository, creates a VM, copies a git checkout plus current tracked and untracked non-ignored files into `/root/repo`, starts a best-effort guest tooling harness that inspects the repo and installs clearly-needed tools with `mise`, and then prefers a host-side `opencode attach` session when the local client supports it. Older host opencode clients fall back to starting `opencode` inside the guest over SSH. The harness runs asynchronously and logs its output inside the guest.

For ACP-aware host tools, `./build/bin/banger vm acp <vm-name>` bridges stdio to guest `opencode acp` over SSH. It uses `/root/repo` when that checkout exists, otherwise `/root`, and `--cwd` lets you override the guest working directory explicitly.

## Web UI

`bangerd` serves a local web UI by default at:

- `http://127.0.0.1:7777`

See the effective URL with:

```bash
./build/bin/banger daemon status
```

Disable it with:

```toml
web_listen_addr = ""
```

## Guest Services

Provisioned images include:

- `banger-vsock-agent`
- guest networking bootstrap
- `mise`
- `opencode`
- a default guest `opencode` service on `0.0.0.0:4096`

If host `~/.local/share/opencode/auth.json` exists, `banger` syncs it into the guest at `/root/.local/share/opencode/auth.json` on VM start. Changes on the host take effect after the VM is restarted.

From the host:

```bash
./build/bin/banger vm ports testbox
opencode attach http://<guest-ip>:4096
```

## Manual Helpers

The shell helpers are now explicit manual workflows under `./build/manual`.

Rebuild a Debian-style manual rootfs:

```bash
make rootfs ARGS='--base-rootfs /abs/path/rootfs.ext4 --kernel /abs/path/vmlinux --initrd /abs/path/initrd.img --modules /abs/path/modules'
```

The output lands in:

- `./build/manual/rootfs-docker.ext4`
- `./build/manual/rootfs-docker.work-seed.ext4`

## Experimental Void Flow

Stage a Void kernel:

```bash
make void-kernel
```

Build the experimental Void rootfs:

```bash
make rootfs-void
```

Register it:

```bash
make void-register
```

That flow uses:

- `./build/manual/void-kernel/`
- `./build/manual/rootfs-void.ext4`
- `./build/manual/rootfs-void.work-seed.ext4`

## Experimental Alpine Flow

Stage an Alpine virt kernel:

```bash
make alpine-kernel
```

Build the experimental Alpine rootfs:

```bash
make rootfs-alpine
```

Register it:

```bash
make alpine-register
```

Create a VM from it:

```bash
./build/bin/banger vm create --image alpine --name alpine-dev
```

That flow uses:

- `./build/manual/alpine-kernel/`
- `./build/manual/rootfs-alpine.ext4`
- `./build/manual/rootfs-alpine.work-seed.ext4`

The experimental Alpine flow stages a pinned Alpine release by default. Override
that pin with `ALPINE_RELEASE=...` when running the `make alpine-kernel` and
`make rootfs-alpine` helpers if you need a different patch release.

Alpine support currently applies to the explicit register-and-run flow above.
The generic `banger image build --from-image ...` path remains Debian/systemd-
oriented and should not be treated as an Alpine image builder.

## Notes

- Firecracker is resolved from `PATH` by default.
- Managed image delete removes the daemon-owned artifact dir.
- The companion vsock helper is internal to the install/build layout, not a user-configured runtime path.