Boost CI speed

[cometkim]

Strategies

Mostly using actions/cache

build-rewatch

Skip build if there are no changes in rewatch sources and its dependencies.

build

Cache APT dependencies

Pre-install Linux dependencies more efficiently using cache-apt-pkgs-action

Cache OPAM installation

Skip OPAM installation as much as possible.

Once it installed, there are three paths can be cached:

• ${{ runner.tool_cache }}/opam/...: Shared storage for binaries installed by setup-* actions. It will contain opam executable.
• ~/.opam: The home directory of OPAM, every modification by OPAM will placed there.
• _opam: Local switch

After caching these three, we can restore OPAM installation by adding PATH and exporting opam env.

Install JSOO ahead of the job

It can be cached with other deps

Results

build-rewatch on ubuntu-latest:

• before: 50s~90s
• after (cached): ~15s

build on ubuntu-latest:

• before: ~360s
• after (cached): ~120s

[cometkim]

The Windows build failure is due to shell compatibility. Fix should be trivial Danm it wasn't

[cometkim]

Note: managing cache

The cache of a public repository is limited to 10GB in total. Once a repository has reached its maximum cache storage, the cache eviction policy will create space by deleting the oldest caches in the repository.

If we want to invalidate the cache at some point, there are several options:

• Change the cache key in the workflow file.
• Change the cache key by combining it with repository variables. Then admins can expire multiple caches at once without creating a new commit.
• Delete directly from the management UI ([repo_url]/actions/caches)
• Use the GitHub CLI. Need gh extension install actions/gh-actions-cache

[cometkim]

hahahahahaha I won this war

[cometkim]

@cknitt I think this will work stably. any remaining feedback?

[cknitt]

Thanks again for the great work!