Rust Cache Action

A GitHub Action that implements smart caching for rust/cargo projects

Example usage

- uses: Swatinem/rust-cache@v1

Specifics

This action tries to be better than just caching the following directories:

~/.cargo/registry
~/.cargo/git
target

It disables incremental compilation and only caches dependencies. The assumption is that we will likely recompile our own crate(s) anyway.

It also separates the cache into 3 groups, each treated differently:

• Registry Index: ~/.cargo/registry/index/<registry>:

  This is always restored from its latest snapshot, and persisted based on the most recent revision.

• Registry Cache: ~/.cargo/registry/cache/<registry>:

  Automatically keyed by the lockfile/toml hash, and is being pruned to only persist the dependencies that are being used.

• target: ./target

  Automatically keyed by the lockfile, toml hash and job, and is being pruned to only persist the dependencies that are being used. This is especially throwing away any intermediate artifacts.