Use setup bazel gha

.github/workflows/main.yml

@@ -13,64 +13,34 @@ on:
 jobs:
   bazel_test:
     runs-on: ubuntu-latest
-    env:
-      # This is where bazelisk caches its downloads of Bazel.
-      BAZELISK_HOME: /home/runner/.cache/bazel_ci/bazelisk
     steps:
       - uses: actions/checkout@v6
       - name: Install Ubuntu dependencies
         run: .github/ci_setup.bash
-      # Restore the most appropriate caches.
-      #
-      # In the below: `github.ref` will be either "refs/pull/<pr_number>/merge"
-      # or "refs/heads/main"; `github.run_number` is a monotonically increasing
-      # serial number; and `github.run_attempt` is a typically 1.
-      #
-      # The `key` declared here will never match (since it encodes the current
-      # run_number) but illustrates the name we'll use to save the caches when
-      # we're done.
-      #
-      # However, one of the `restore-keys` patterns *should* always match. The
-      # effects we should see from the `restore-keys` patterns are:
-      #
-      # * When building the `main` branch, we'll always pull the most recently
-      #   updated main caches. Both restore keys say "pip-refs/heads/main-" and
-      #   the prior archives are named, e.g., "pip-refs/heads/main-####-#".
-      #   GitHub will use the *most recently saved* archive name that matches
-      #   the restore key prefix (no matter the lexicographic ordering of
-      #   the ####-# part).
-      #
-      # * Ditto for the first build of a PR; the first restore key will not
-      #   match anything, so it falls back to the main caches.
-      #
-      # * For subsequent builds of a PR, the first restore key, e.g.,
-      #   "pip-refs/pull/###/merge-" should match the most recently saved PR key
-      #   "pip-refs/pull/###/merge-####-#".
-      - uses: actions/cache/restore@v5
+      # Cache python dependencies with setup-python.
+      # Uses the hash of the dependency file (pyproject.toml or requirements.txt)
+      # as part of the cache key. For pip, this caches the global cache directory.
+      # Use setup-bazel for disk and repository caching.
+      - uses: bazel-contrib/[email protected]
         with:
-          path: ~/.cache/pip
-          # N.B. The "-mumble" suffix below will never match; it's a placeholder
-          # for the nonce appended to the cache key. Instead, the restore-keys
-          # will always be used for restoring.
-          key: pip-${{ github.ref }}-${{ github.run_number }}-${{ github.run_attempt }}
-          restore-keys: |
-            pip-${{ github.ref }}-
-            pip-refs/heads/main-
-      - uses: actions/cache/restore@v5
-        with:
-          path: ~/.cache/bazel_ci
-          key: bazel_ci-${{ github.ref }}-${{ github.run_number }}-${{ github.run_attempt }}
-          restore-keys: |
-            bazel_ci-${{ github.ref }}-
-            bazel_ci-refs/heads/main-
-      - name: Report cache sizes
-        run: |
-          du -ms ~/.cache/pip || true
-          du -ms ~/.cache/bazel_ci/* || true
+          # Use the cached Bazelisk version, or download if not found.
+          bazelisk-cache: true
+          # Enable the disk cache and share it across all workflows
+          # (i.e., across master and pull requests).
+          # We want all builds to start from a warm cache, and we're not too
+          # concerend about pull request builds "polluting" master builds.
+          disk-cache: true
+          # Share repository cache globally as well. If repository-cache is set to true,
+          # it uses the hash of a few bazel files as the key for the cache. You can set
+          # your own list of files to use to calculate the key by passing them below.
+          # Passing an empty string tells setup-bazel to use the same key
+          # every time, regardless of any changes to any files.
+          repository-cache: ""
+          # This dumps configuration details to the log.
+          bazelrc: common --announce_rc=yes
       # Actual testing.
       - name: Bazel Test
         run: |
-          ln -s .github/ci.bazelrc user.bazelrc
           ./bazel test //...
       # Save the test outputs to allow for eyeball verification when relevant.
       - name: Archive test outputs
@@ -79,20 +49,6 @@ jobs:
           name: test_outputs
           path: |
             .bazel/testlogs/examples/ball_bin_test/test.outputs/outputs.zip
-      # Save the updated cache snapshots, so we never do the same work twice.
-      # By default, actions/cache only saves after a successful workflow, but
-      # our caches are bags of files where we only ever add new files (not change
-      # an existing files), so it's always safe to snapshot.
-      - uses: actions/cache/save@v5
-        if: always()
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ github.ref }}-${{ github.run_number }}-${{ github.run_attempt }}
-      - uses: actions/cache/save@v5
-        if: always()
-        with:
-          path: ~/.cache/bazel_ci
-          key: bazel_ci-${{ github.ref }}-${{ github.run_number }}-${{ github.run_attempt }}
   install_test:
     runs-on: ubuntu-latest
     strategy:

MODULE.bazel

@@ -9,6 +9,7 @@ bazel_dep(name = "rules_python", version = "1.7.0")
 # version of Python, so we'll pin ourselves to exactly that version.
 PYTHON_VERSION = "3.11"
 
+# TODO: Remove this line after GHA succeeds
 python = use_extension("@rules_python//python/extensions:python.bzl", "python")
 python.toolchain(python_version = PYTHON_VERSION)
 use_repo(python, "python_versions")