Install — Nix

Nexo ships a Nix flake that pins the toolchain (Rust 1.80, MSRV) and the native build deps so a contributor or operator can go from clean shell to working binary without touching the host system.

Run without installing

nix run github:lordmacu/nexo-rs -- --help

First invocation builds from source (~3-5 min on cold cache); subsequent runs hit the local Nix store.

Build a local binary

nix build github:lordmacu/nexo-rs
./result/bin/nexo --help

The binary is the same nexo produced by cargo build --release --bin nexo. Outputs a result/ symlink the operator can link into /usr/local/bin/ or copy elsewhere.

Contributor dev shell

git clone https://github.com/lordmacu/nexo-rs
cd nexo-rs
nix develop

Drops you into a shell with:

rustc 1.80 + cargo + clippy + rustfmt + rust-src
cargo-edit, cargo-watch, cargo-nextest, cargo-deny
mdbook + mdbook-mermaid (for mdbook build docs)
sqlite, pkg-config, openssl, libgit2 (build deps)

RUST_LOG=info is exported by default. The toolchain version is pinned in flake.nix — bump in lockstep with [workspace.package].rust-version in Cargo.toml.

What the flake does NOT install

The nexo binary alone is not enough for full functionality. Runtime tools the channel plugins shell out to live at the system level, not in the flake:

Chrome / Chromium — required by the browser plugin
cloudflared — used by the tunnel plugin
ffmpeg — media transcoding for WhatsApp voice notes
tesseract-ocr — OCR skill
yt-dlp — the yt-dlp extension

Operators install these via their distro's package manager. The native install guide lists the apt / pacman / brew commands. The Docker image bundles all of them — that's the path of least friction for a "just works" deploy.

Pinning a release

Once v* tags are published, pin to a specific release:

nix run github:lordmacu/nexo-rs/v0.1.1 -- --help

Or in a flake input:

{
  inputs.nexo-rs.url = "github:lordmacu/nexo-rs/v0.1.1";
}

Verifying the build

nix flake check

Runs nix flake check — verifies the flake metadata, evaluates all outputs (packages, apps, devShells, formatter) without actually building. Useful in CI to catch flake regressions early.

Troubleshooting

"experimental feature 'flakes' is disabled" — add to ~/.config/nix/nix.conf:
```
experimental-features = nix-command flakes
```
First build is very slow — the build re-fetches and re-compiles every cargo dependency in the sandbox. Subsequent builds are cached. A future Phase 27.x will publish a cachix cache so nix build pulls the binary directly.
Build fails on macOS arm64 — git2-rs occasionally lags on Apple silicon. Workaround: build the binary inside the Docker image instead (see Docker).

Nexo-rs