GitLab CI Pipeline for Rust Projects

Rust CI Pipeline in GitLab

Rust compilation is notoriously slow, making caching critical for practical CI pipelines. This configuration minimizes build times while maintaining thorough quality checks.

Pipeline Configuration

stages:
  - check
  - test
  - build

variables:
  CARGO_HOME: "$CI_PROJECT_DIR/.cargo"

fmt:
  stage: check
  image: rust:1.77-slim
  script:
    - rustup component add rustfmt
    - cargo fmt -- --check

clippy:
  stage: check
  image: rust:1.77-slim
  script:
    - rustup component add clippy
    - cargo clippy -- -D warnings
  cache:
    key: rust-cache
    paths:
      - .cargo/registry/
      - target/
    policy: pull-push

test:
  stage: test
  image: rust:1.77-slim
  script:
    - cargo test --all-features
  cache:
    key: rust-cache
    paths:
      - .cargo/registry/
      - target/
    policy: pull-push
  artifacts:
    paths:
      - target/debug/
    expire_in: 1 hour

build_release:
  stage: build
  image: rust:1.77-slim
  script:
    - cargo build --release
  cache:
    key: rust-cache
    paths:
      - .cargo/registry/
      - target/
    policy: pull
  artifacts:
    paths:
      - target/release/
    expire_in: 1 week
  rules:
    - if: '$CI_COMMIT_BRANCH == "main"'

Caching Strategy

Rust caches are large (often 1-2 GB) because they include compiled dependencies. Caching both .cargo/registry/ (downloaded crates) and target/ (compiled artifacts) dramatically reduces build times after the first run.

Clippy with -D warnings

The -D warnings flag promotes all clippy warnings to errors, ensuring code quality standards are enforced. This is stricter than the default but catches many common mistakes.

Release builds on main only

The rules section ensures that the expensive release build only runs on the main branch, saving CI minutes on feature branches.