# OpenCode Sandbox

A rootless Podman container for running [OpenCode](https://github.com/anomalyco/opencode) with a pinned toolchain — Java, Node, pnpm, git — without touching your host machine's environment.

## What this gives you

- A hash-pinned, integrity-verified build of OpenCode (not "latest" — an exact version, checked against a SHA256 captured at build time).
- JDK 25 (LTS), Node 24 (LTS), pnpm, git, curl, openssh-client.
- The current directory mounted read-write as `/workspace`.
- OpenCode's config, data, and session state shared across every workdir/container, so logging in once carries over everywhere.
- Every container joined to a shared Podman network so it can reach other dev containers by name.

## Requirements

- [Podman](https://podman.io/) (rootless).
- On macOS: a running `podman machine` — `make` will start a stopped one automatically, but if you've never run Podman before you need to initialize one first:
  ```
  podman machine init
  ```
- GNU Make (macOS's bundled Make 3.81 works fine; the Makefile deliberately avoids features added in 3.82+).

## Usage

```
make build      # build (or rebuild) the container image
make opencode   # launch the OpenCode TUI in the current directory
make shell      # open a bash shell in the container instead
make install    # build, then install a global `opencode-sandbox` shortcut (see below)
```

Run `make opencode` or `make shell` from any project directory — the image is shared, so there's nothing per-project to set up.

### `make install`

Installs a shim at `~/.local/bin/opencode-sandbox` that runs `make opencode`
against this repo's Makefile, using whatever directory you're standing in —
not this repo — as `/workspace`. Once installed, `opencode-sandbox` works as
a global command from any directory, no `cd` into this repo required. (Only
`opencode` gets a shortcut; `make shell` still has to be run from here.)

It also makes sure `~/.local/bin` is on `PATH` for future shells, based on
your login shell (`$SHELL`):

- zsh → appended to `~/.zshrc` (or `~/.zshenv` if that's the only one of the two that already exists; `~/.zshrc` is created if neither does)
- bash → `~/.bash_profile` on macOS, `~/.bashrc` on Linux (created if missing)
- fish → added via `fish_add_path` (no config file edit needed)
- anything else → appended to `~/.profile`

The edit is wrapped in `# >>> opencode-sandbox >>>` markers so re-running
`make install` never duplicates it, and is skipped entirely if
`~/.local/bin` is already on `PATH`.

## How it's put together

**Containerfile** — multi-stage build on `debian:trixie-slim`:
- JDK and Node are copied in from their official upstream images (`eclipse-temurin:25-jdk-noble`, `node:24-trixie-slim`) rather than apt-installed, keeping the final image slim while staying on a mainstream glibc distro (Alpine/musl is avoided — it breaks JVM and native Node addon compatibility).
- pnpm is installed via its own standalone installer script, pinned to a specific version.
- OpenCode is downloaded directly from its canonical GitHub releases (`github.com/anomalyco/opencode`) for the container's architecture, and its SHA256 is checked against a hash pinned in the Containerfile before it's installed — there's no maintainer-published signature for OpenCode releases, so this hash is captured by hand and is the actual root of trust here. Bump `OPENCODE_VERSION` and re-run the `sha256sum` steps documented in the Containerfile's comments whenever you upgrade it.
- A few build-time smoke tests (`ldd`, `java -version`, `node --version`, etc.) fail the build immediately if anything is broken, rather than surfacing at first `make opencode`.

**Makefile** — four targets:
- `build` builds the image.
- `opencode` and `shell` both run the container with the same flags: `--userns=keep-id` (so files created in the container are owned by your real host user, not root — verified: rootless Podman's user-namespace remapping means `id` shows `root` *inside* the container's own namespace view, but the file lands on the host owned by your actual UID/GID), the current directory bind-mounted to `/workspace`, and OpenCode's three XDG directories bind-mounted from your home directory:

  | Host path | Container path | Contents |
  |---|---|---|
  | `~/.config/opencode` | `/home/dev/.config/opencode` | settings, plugins, themes |
  | `~/.local/share/opencode` | `/home/dev/.local/share/opencode` | auth, database, snapshots |
  | `~/.local/state/opencode` | `/home/dev/.local/state/opencode` | session/model history, locks |

  Because these are real host paths shared by every container regardless of workdir, logging into OpenCode once carries over to every project you use the sandbox in.

- Both run targets join a shared, auto-created Podman network (`opencode-sandbox-net`) under a `--network-alias` derived from the current directory's name, so a container started from another dev-container setup on the same network can reach this one by that name (and vice versa).

## macOS-specific notes

- Podman on macOS runs everything inside a Linux VM (`podman machine`, backend `libkrun`/`applehv`, virtiofs file sharing). The Makefile detects this and starts a stopped machine automatically before `build`, `opencode`, or `shell`.
- SELinux volume-relabeling suffixes (`:Z`/`:z`) are intentionally omitted — macOS's host filesystem has no SELinux concept, so they'd be a no-op.
- Known virtiofs limitation: inotify/file-watch events from the host don't propagate into the container. Not a blocker for normal use, just worth knowing if a tool inside the container tries to watch `/workspace` for live host-side changes.

## Connecting to other dev containers

Any other container you attach to the `opencode-sandbox-net` network (`podman network connect opencode-sandbox-net <container>`, or by starting it with `--network opencode-sandbox-net`) can resolve and reach this sandbox by its workdir-derived alias, and vice versa.