Caching for GitHub Workflows was released just before GA: GitHub - actions/cache: Cache dependencies and build outputs in GitHub Actions
They provide Rust/Cargo examples:
- name: Cache cargo registry
uses: actions/cache@v1
with:
path: ~/.cargo/registry
key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
- name: Cache cargo index
uses: actions/cache@v1
with:
path: ~/.cargo/git
key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
- name: Cache cargo build
uses: actions/cache@v1
with:
path: target
key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
In terms of evaluating GitHub Actions for rust-analyzer, I'm happy to help set it up.