Docker+Rust Buildcache

Describing two strategies to cache rust builds within docker in the minimal example repo.

Caching Cargo and Target Folders

To achieve local like build caching you simply need mount cargos registry and your build target folder as a docker cache mount.

A minimal example can be found in this branch: https://github.com/benmarten/sccache-docker-test/tree/no-sccache

Minimal rust+sccache compilation example with docker cache volume.

If you want your cache to outlive the target folder or you want to share the buildcache between multiple clients/nodes, you can use sccache to achieve that. Check out the example in this master branch:

To see sccache in action within the docker container, run:

DOCKER_BUILDKIT=1 docker build . --progress=plain

then change the echo 1 line to echo 2 (to force recompilation from this line), and rerun the docker command, you'll see cache hits in sccache's stats ;)

To clear the docker cache mount: docker builder prune --filter type=exec.cachemount