Rust Deploy

DevOps & Security

rust-deploy

Rust Deploy is an Agent Skill for devops & security published in the nixopus/nixopus repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

Build and deploy Rust applications — version detection, release binaries, cargo-chef, and Dockerfile patterns. Use when deploying a Rust project, or when Cargo.toml is detected.

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QUICK START

How to use this skill

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Open your project in Codex.
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Prompt to paste

Inspect the Agent Skill at https://github.com/nixopus/nixopus/blob/HEAD/api/skills/rust-deploy/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/rust-deploy, but wait for my approval before writing files or running scripts.

Copying this prompt does not install or run the skill. Review third-party files before use.

Rust Deployment

Detection

Project is Rust if Cargo.toml or cargo.toml exists.

Versions

Rust version priority:

rust-toolchain.toml → toolchain.channel
Cargo.toml → package.rust-version
.rust-version file
Cargo.toml → package.edition (maps to minimum Rust version)
Defaults to latest stable (1.89)

Build

Build Command

cargo build --release
Binary: target/release/<package-name>
Package name from Cargo.toml → [package].name

Entry Resolution

Binary crate: src/main.rs
Multi-binary: src/bin/<name>.rs → binary name matches filename
Library + binary: [bin] section in Cargo.toml

Output

Build output: target/release/<name>
Start command: ./bin/<project-name> or ./target/release/<name>

Runtime Variables

Variable	Purpose
`ROCKET_ADDRESS`	Rocket bind address (use `0.0.0.0` for containers)
`PORT`	Port for web servers (default 8080)

Port Detection

PORT in .env / .env.example
Source code patterns: :8080, bind, TcpListener in main.rs
Default: 8080

Framework / Library Detection

Crate	Category
`axum`	Web
`actix-web`	Web
`rocket`	Web
`warp`	Web
`tokio`	Async runtime
`tower`	Middleware

Install Stage Optimization

Copy in order:

Cargo.toml, Cargo.lock
src/ (or full source)

BuildKit Caching

Cache key	Path
`cargo_registry`	`~/.cargo/registry`
`cargo_git`	`~/.cargo/git`
`cargo_target`	`target/`

Base Images

Stage	Image
Build	`rust:1.89-bookworm` or `rust:1.89-alpine`
Runtime	`debian:bookworm-slim` or `gcr.io/distroless/cc`

For Alpine build: may need musl-dev for fully static binary.

Dockerfile Patterns

Multi-Stage (Debian)

FROM rust:1.89-bookworm AS build
WORKDIR /app
COPY Cargo.toml Cargo.lock ./
RUN mkdir src && echo "fn main() {}" > src/main.rs
RUN cargo build --release
COPY src ./src
RUN touch src/main.rs && cargo build --release

FROM debian:bookworm-slim
RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/lib/apt/lists/*
WORKDIR /app
COPY --from=build /app/target/release/<binary-name> .
EXPOSE 8080
CMD ["./<binary-name>"]

Cargo Chef (faster layer cache)

FROM rust:1.89-bookworm AS chef
RUN cargo install cargo-chef

FROM chef AS planner
WORKDIR /app
COPY . .
RUN cargo chef prepare --recipe-path recipe.json

FROM chef AS build
WORKDIR /app
COPY --from=planner /app/recipe.json .
RUN cargo chef cook --release --recipe-path recipe.json
COPY . .
RUN cargo build --release

FROM debian:bookworm-slim
RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/lib/apt/lists/*
WORKDIR /app
COPY --from=build /app/target/release/<binary-name> .
EXPOSE 8080
CMD ["./<binary-name>"]

Simple (no chef)

FROM rust:1.89-bookworm AS build
WORKDIR /app
COPY . .
RUN cargo build --release

FROM debian:bookworm-slim
RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/lib/apt/lists/*
WORKDIR /app
COPY --from=build /app/target/release/<binary-name> .
EXPOSE 8080
CMD ["./<binary-name>"]

Gotchas

The dummy main.rs trick (echo "fn main() {}" > src/main.rs) caches dependency compilation, but touch src/main.rs is needed afterward to invalidate the binary build cache
Cargo.lock must be committed for binary crates — without it, dependency versions are resolved fresh on every build
Alpine builds need musl-dev, but crates using OpenSSL also need openssl-dev and pkgconfig
Rust builds are memory-intensive — cargo build --release -j 2 limits parallelism to avoid OOM kills in resource-constrained environments
Cargo chef prepare requires the full source tree — it scans code to compute the dependency recipe