Rust Deployable Service

Use this skill when a Rust service needs to move from local development to a repeatable container or cloud deployment. Keep runtime configuration explicit, builds reproducible, and health checks boring.

Core Workflow

1. Inspect Cargo.toml, workspace layout, Dockerfile, .dockerignore, config files, migrations, .sqlx/, CI, and deployment docs.
2. Identify the binary entrypoint and runtime dependencies: database, Redis, external APIs, TLS roots, static files, templates, migrations, and config.
3. Separate build-time and runtime configuration. Never bake production secrets into images.
4. Use hierarchical config with environment overrides for deployment-specific values.
5. Use a multi-stage Docker build and copy only the runtime binary and needed assets into the final image.
6. Account for SQLx query checking. Use SQLX_OFFLINE=true with checked-in .sqlx/ metadata or provide a build-time database intentionally.
7. Add health and readiness checks that match real dependencies.
8. Run the bundled Docker preflight or the repository's equivalent CI command.

Configuration Rules

Read references/configuration.md when adding config files, environment variables, or secret handling.

• Keep local defaults convenient and production defaults conservative.
• Validate config at startup before binding the server when possible.
• Store secrets in environment variables or the deployment secret manager.
• Avoid reading environment variables deep inside handlers or repositories.

Docker Rules

Read references/docker-rust.md before changing Docker builds.

• Use dependency caching deliberately; avoid invalidating the whole build on every source edit when practical.
• Use --locked for release builds if the repo commits Cargo.lock.
• Include CA certificates when outbound HTTPS is required.
• Copy migrations, templates, and static assets only if the binary needs them at runtime.
• Run as a non-root user when the deployment platform supports it.

Verification

Run from the Rust project root when Docker is part of the delivery path:

path/to/rust-deployable-service/scripts/docker-preflight.sh

The script builds an image. It only runs a smoke command when RUST_DEPLOY_SMOKE_COMMAND is set, because services often need environment and infrastructure to start successfully.

Reference Files

• references/configuration.md: typed config loading, overrides, validation, and secrets.
• references/docker-rust.md: multi-stage builds, SQLx offline builds, runtime assets, and image checks.