[BUILD] Add support for bzlmod (open-telemetry#2608)

* Add support for bzlmod

This adds support for bzlmod, which is bazel's new dependency resolution
system.

Theoretically we could now remove the previous dependency management
configuration which required flattening all the dependencies, but I left
it here for now for users using old versions of bazel.

.github/workflows/ci.yml

@@ -537,6 +537,27 @@ jobs:
     - name: run tests
       run: ./ci/do_ci.sh bazel.test
 
+  bazel_no_bzlmod_test:
+    name: Bazel without bzlmod
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: 'recursive'
+    - name: Mount Bazel Cache
+      uses: actions/cache@v4
+      env:
+        cache-name: bazel_cache
+      with:
+        path: /home/runner/.cache/bazel
+        key: bazel_test
+    - name: setup
+      run: |
+        sudo ./ci/setup_ci_environment.sh
+        sudo ./ci/install_bazelisk.sh
+    - name: run tests
+      run: ./ci/do_ci.sh bazel.no_bzlmod.test
+
   bazel_test_async:
     name: Bazel with async export
     runs-on: ubuntu-latest

.gitignore

@@ -37,6 +37,7 @@
 *.app
 
 # Bazel files
+MODULE.bazel.lock
 /bazel-*
 
 # Mac

MODULE.bazel

@@ -0,0 +1,25 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+
+module(
+    name = "opentelemetry-cpp",
+    version = "0",
+    compatibility_level = 0,
+    repo_name = "io_opentelemetry_cpp",
+)
+
+bazel_dep(name = "abseil-cpp", version = "20240116.1", repo_name = "com_google_absl")
+bazel_dep(name = "bazel_skylib", version = "1.5.0")
+bazel_dep(name = "curl", version = "8.4.0")
+bazel_dep(name = "grpc", version = "1.62.1", repo_name = "com_github_grpc_grpc")
+bazel_dep(name = "nlohmann_json", version = "3.11.3", repo_name = "github_nlohmann_json")
+bazel_dep(name = "opentelemetry-proto", version = "1.3.1", repo_name = "com_github_opentelemetry_proto")
+bazel_dep(name = "opentracing-cpp", version = "1.6.0", repo_name = "com_github_opentracing")
+bazel_dep(name = "platforms", version = "0.0.8")
+bazel_dep(name = "prometheus-cpp", version = "1.2.4", repo_name = "com_github_jupp0r_prometheus_cpp")
+bazel_dep(name = "protobuf", version = "26.0", repo_name = "com_google_protobuf")
+bazel_dep(name = "rules_proto", version = "5.3.0-21.7")
+bazel_dep(name = "zlib", version = "1.3.1.bcr.1")
+
+bazel_dep(name = "google_benchmark", version = "1.8.3", dev_dependency = True, repo_name = "com_github_google_benchmark")
+bazel_dep(name = "googletest", version = "1.14.0.bcr.1", dev_dependency = True, repo_name = "com_google_googletest")

WORKSPACE.bzlmod

@@ -0,0 +1,4 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+
+# Disables the default WORKSPACE when using bzlmod

ci/do_ci.sh

@@ -459,6 +459,10 @@ EOF
   make load_plugin_example
   examples/plugin/load/load_plugin_example ${PLUGIN_DIR}/libexample_plugin.so /dev/null
   exit 0
+elif [[ "$1" == "bazel.no_bzlmod.test" ]]; then
+  bazel $BAZEL_STARTUP_OPTIONS build --enable_bzlmod=false $BAZEL_OPTIONS //...
+  bazel $BAZEL_STARTUP_OPTIONS test --enable_bzlmod=false $BAZEL_TEST_OPTIONS //...
+  exit 0
 elif [[ "$1" == "bazel.test" ]]; then
   bazel $BAZEL_STARTUP_OPTIONS build $BAZEL_OPTIONS //...
   bazel $BAZEL_STARTUP_OPTIONS test $BAZEL_TEST_OPTIONS //...