Simplify CI setup and use prebuilt protoc (#90)

Author: fmeum

.bazelrc

@@ -13,6 +13,15 @@ common --check_direct_dependencies=off
 # Improve build caching by redacting environment variables.
 common --incompatible_strict_action_env
 
+# Avoid building protoc from source.
+common --incompatible_enable_proto_toolchain_resolution
+
+# Debug where options came from
+common:ci --announce_rc
+# Don't rely on test logs being easily accessible from the test runner,
+# though it makes the log noisier.
+common:ci --test_output=errors
+
 # Load any settings specific to the current user.
 # .bazelrc.user should appear in .gitignore so that settings are not shared with team members
 # This needs to be last statement in this

.github/workflows/ci.bazelrc

@@ -26,42 +26,15 @@ jobs:
       matrix:
         os: [ubuntu-20.04, macos-12, windows-2022]
         bazelversion: [6.4.0, last_rc, last_green]
-        folder: [".", examples]
-        exclude:
-          - os: windows-2022
-            folder: "."
-          - os: macos-12
-            folder: "."
-          - bazelversion: last_green
-            folder: "."
-          - bazelversion: 6.4.0
+        folder: [examples]
+        include:
+          - os: ubuntu-20.04
+            bazelversion: last_rc
             folder: "."
 
     steps:
       - uses: actions/checkout@v4
 
-      # Cache build artifacts so that the next ci build is incremental.
-      # Because github action caches cannot be updated after a build, we need to
-      # store the contents of each build in a unique cache key, then fall back to loading
-      # it on the next ci run. We use hashFiles(...) in the key and restore-keys- with
-      # the prefix to load the most recent cache for the branch on a cache miss. You
-      # should customize the contents of hashFiles to capture any bazel input sources,
-      # although this doesn't need to be perfect. If none of the input sources change
-      # then a cache hit will load an existing cache and bazel won't have to do any work.
-      # In the case of a cache miss, you want the fallback cache to contain most of the
-      # previously built artifacts to minimize build time. The more precise you are with
-      # hashFiles sources the less work bazel will have to do.
-      # We do not cache downloaded external artifacts as these are generally
-      # faster to download again than to fetch them from the GitHub actions
-      # cache.
-      - name: Mount bazel caches
-        uses: actions/cache@v4
-        with:
-          path: |
-            ~/.cache/bazel
-          key: bazel-cache-${{ hashFiles('**/BUILD.bazel', '**/*.bzl', '**/MODULE.bazel', '**/.bazelrc') }}
-          restore-keys: bazel-cache-
-
       - name: Configure Bazel version
         working-directory: ${{ matrix.folder }}
         run: echo "${{ matrix.bazelversion }}" > .bazelversion
@@ -76,9 +49,9 @@ jobs:
 
       - name: bazel test //...
         working-directory: ${{ matrix.folder }}
-        run: bazel --bazelrc=${{ github.workspace }}/.github/workflows/ci.bazelrc --bazelrc=.bazelrc test //...
+        run: bazel test --config=ci //...
 
       - name: bazel coverage //...
         if: matrix.os == 'ubuntu-20.04' && matrix.folder == 'examples'
         working-directory: ${{ matrix.folder }}
-        run: bazel --bazelrc=${{ github.workspace }}/.github/workflows/ci.bazelrc --bazelrc=.bazelrc coverage //...
+        run: bazel coverage --config=ci //...

.github/workflows/ci.yaml

@@ -2,3 +2,4 @@ bazel-*
 .bazelrc.user
 .idea/
 .ijwb/
+MODULE.bazel.lock

.gitignore

@@ -12,4 +12,38 @@ bazel_dep(name = "buildifier_prebuilt", version = "6.1.0", dev_dependency = True
 bazel_dep(name = "gazelle", version = "0.33.0", dev_dependency = True, repo_name = "bazel_gazelle")
 bazel_dep(name = "platforms", version = "0.0.6", dev_dependency = True)
 bazel_dep(name = "rules_testing", version = "0.4.0", dev_dependency = True)
-bazel_dep(name = "stardoc", version = "0.6.2", dev_dependency = True)
+bazel_dep(name = "stardoc", dev_dependency = True)
+git_override(
+    module_name = "stardoc",
+    commit = "3baa5d1761970c6285d2ac9c3adccfaac42f54c5",
+    remote = "https://github.com/bazelbuild/stardoc.git",
+)
+
+bazel_dep(name = "rules_java", version = "7.6.1", dev_dependency = True)
+bazel_dep(name = "rules_proto", version = "6.0.0", dev_dependency = True)
+bazel_dep(name = "toolchains_protoc", version = "0.3.0", dev_dependency = True)
+
+protoc = use_extension(
+    "@toolchains_protoc//protoc:extensions.bzl",
+    "protoc",
+    dev_dependency = True,
+)
+protoc.toolchain(
+    # Creates a repository to satisfy well-known-types dependencies such as
+    # deps=["@com_google_protobuf//:any_proto"]
+    google_protobuf = "com_google_protobuf",
+    # Pin to any version of protoc
+    version = "v26.0",
+)
+
+protobuf_java_repos = use_extension(
+    "//tools:extensions.bzl",
+    "protobuf_java_repo",
+    dev_dependency = True,
+)
+use_repo(protobuf_java_repos, "protobuf_java")
+
+register_toolchains(
+    "//docs/...",
+    dev_dependency = True,
+)

MODULE.bazel

@@ -1,10 +1,25 @@
 # This load statement must be in the docs/ package rather than anything users depend on
 # so that the dependency on stardoc doesn't leak to them.
 load("@aspect_bazel_lib//lib:docs.bzl", "stardoc_with_diff_test", "update_docs")
+load("@rules_proto//proto:proto_lang_toolchain.bzl", "proto_lang_toolchain")
 
 stardoc_with_diff_test(
     name = "defs",
     bzl_library_target = "//with_cfg:defs",
 )
 
 update_docs(name = "update")
+
+# Precompiled proto toolchain for stardoc
+proto_lang_toolchain(
+    name = "protoc_java_toolchain",
+    command_line = "--java_out=$(OUT)",
+    progress_message = "Generating java_proto_library %{label}",
+    runtime = "@protobuf_java//jar",
+)
+
+toolchain(
+    name = "protoc_java_toolchain.registration",
+    toolchain = ":protoc_java_toolchain",
+    toolchain_type = "@rules_java//java/proto:toolchain_type",
+)

docs/BUILD.bazel

@@ -25,3 +25,9 @@ common:windows --noincompatible_strict_action_env
 common:windows --test_env=PATH
 # Allow build to start before all external deps have been fetched.
 common --experimental_merged_skyframe_analysis_execution
+
+# Debug where options came from
+common:ci --announce_rc
+# Don't rely on test logs being easily accessible from the test runner,
+# though it makes the log noisier.
+common:ci --test_output=errors

examples/.bazelrc

@@ -0,0 +1,11 @@
+load("@bazel_skylib//lib:modules.bzl", "modules")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_jar")
+
+def _protobuf_java_repo():
+    http_jar(
+        name = "protobuf_java",
+        urls = ["https://repo1.maven.org/maven2/com/google/protobuf/protobuf-java/4.26.1/protobuf-java-4.26.1.jar"],
+        integrity = "sha256-CRkz5YcK+BB0gyb3rOSmc6ynISUxd1QoQvBEtUbxQoI=",
+    )
+
+protobuf_java_repo = modules.as_extension(_protobuf_java_repo)