banger/AGENTS.md

Repository Guidelines

Always run make build before commit.

Project Structure

• cmd/banger and cmd/bangerd are the main user entrypoints.
• internal/ contains the daemon, CLI, RPC, storage, Firecracker integration, guest helpers, and the experimental web UI.
• internal/daemon/ is the composition root; pure helpers live in its subpackages (opstate, dmsnap, fcproc, imagemgr, session, workspace). See internal/daemon/ARCHITECTURE.md.
• internal/imagecat/ and internal/kernelcat/ embed the image + kernel catalogs.
• images/golden/ is the Dockerfile for the debian-bookworm catalog entry.
• scripts/ contains manual helper workflows for rootfs, kernel, and bundle preparation.
• build/bin/ is the canonical source-checkout build output.
• build/manual/ is the canonical source-checkout location for manual rootfs/kernel artifacts.

Build and Test

• make build builds ./build/bin/banger, ./build/bin/bangerd, and ./build/bin/banger-vsock-agent.
• make test runs go test ./....
• make lint runs gofmt -l, go vet ./..., and shellcheck --severity=error on scripts/*.sh. Run before commits.
• ./build/bin/banger doctor checks host readiness.
• ./build/bin/banger vm run is the primary user-facing entry point — auto-pulls the default image + kernel from the catalogs if missing.
• ./build/bin/banger image pull <name> uses the bundle catalog (fast) when <name> is a catalog entry, or falls through to the OCI path for arbitrary registry refs. See docs/image-catalog.md and docs/oci-import.md.
• ./build/bin/banger image register ... registers an unmanaged host-side image stack.
• ./build/bin/banger image build --from-image <image> builds a managed image from an existing one.
• ./build/bin/banger image promote <image> copies an unmanaged image into daemon-owned managed artifacts.
• scripts/make-generic-kernel.sh builds a Firecracker-optimized vmlinux from upstream sources. scripts/publish-kernel.sh <name> publishes it to the kernel catalog.
• scripts/publish-golden-image.sh rebuilds + publishes the golden image bundle and patches the image catalog.

Image Model

• Managed images own the full boot set: rootfs, optional work-seed, kernel, optional initrd, and optional modules.
• The image catalog ships pre-built bundles. vm run auto-pulls the default catalog entry; image pull <name> can be invoked explicitly.
• default_image_name defaults to debian-bookworm. On miss, the daemon auto-pulls from imagecat before surfacing "not found".
• Kernel references follow the same auto-pull pattern against kernelcat.

Config

• Config lives at ~/.config/banger/config.toml.
• Firecracker comes from PATH by default, or firecracker_bin.
• SSH uses ssh_key_path or an auto-managed default key at ~/.config/banger/ssh/id_ed25519.

Coding Style

• Prefer small, direct Go code and standard library solutions.
• Keep shell scripts strict with set -euo pipefail.
• Use gofmt for Go formatting.
• When a CLI accepts either an inline string or a file input, always prefer the file-based form.
• For shell commands and AI/LLM tooling, prefer passing files as input whenever the CLI allows it.
• Create temporary files as needed to follow the file-first rule.
• Examples: use git commit -F <file> instead of git commit -m <message>, and use prompt files instead of inline prompt strings when invoking LLM CLIs.

Testing Guidance

• Primary automated coverage is go test ./....
• For lifecycle changes, smoke-test with vm run end-to-end (covers create + start + boot + ssh).
• If guest provisioning changes, document whether existing images must be rebuilt or recreated.

Security

• Do not commit secrets.
• VM workflows require sudo and /dev/kvm.
• The default SSH key is local configuration, not a checked-in runtime artifact.