PR #2483: Bazel build support for building rust and beto-core targets

Imported from GitHub PR https://github.com/google/nearby/pull/2483

This adds the necessary build rules to build with the LDT rust implementation in bazel, currently it is compiled out by a compiler flag.

This also updates the C++ standard to C++20 in order to be compatible with beto-core's targets
Copybara import of the project:

--
b28eabb2be386bfad4d71df94b7dd77fe34b6b13 by Nabil Wadih <nwadih@google.com>:

Bazel build support for building rust and beto-core targets

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765f8076642bc54c6a500e5f91c942bcfea55b39 by Nabil Wadih <nwadih@google.com>:

Bazel build support for building rust and beto-core targets

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3658bdc10dbe8f0bb912e233b411b153179a79eb by Nabil Wadih <nwadih@google.com>:

Bazel build support for building rust and beto-core targets

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65321ef4fcdf9d1cbdfe866bd3364f3701819a9c by Nabil Wadih <nwadih@google.com>:

Bazel build support for building rust and beto-core targets

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f52590fd46a04d081c7175a1e342212c1e9174cd by Nabil Wadih <nabil.wadih@gmail.com>:

Update validate.yaml
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eef6b260cb12701e3dee4a2e41a98ad7aa23183b by Nabil Wadih <nabil.wadih@gmail.com>:

Update validate.yaml
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b47f67138310263003db29cf05b93f2a60fe487e by Nabil Wadih <nwadih@google.com>:

Bazel build support for building rust and beto-core targets

Merging this change closes #2483

PiperOrigin-RevId: 627873727

.bazelrc

@@ -1,4 +1,4 @@
-build --action_env=BAZEL_CXXOPTS=-std=c++17
+build --action_env=BAZEL_CXXOPTS=-"std=c++20"
 # Definition of --config=memcheck
 build:memcheck --strip=never --test_timeout=3600
-build --sandbox_block_path=/usr/local
+common --enable_bzlmod

.github/workflows/validate.yaml

@@ -46,11 +46,11 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - name: Build Connections
-      run: CC=clang CXX=clang++ bazel build --copt='-DGITHUB_BUILD' //connections:core
+      run: CC=clang-15 CXX=clang-15++ bazel build --copt='-DGITHUB_BUILD' //connections:core
     - name: Build Presence
-      run: CC=clang CXX=clang++ bazel build --copt='-DGITHUB_BUILD' //presence
+      run: CC=clang-15 CXX=clang-15++ bazel build --copt='-DGITHUB_BUILD' //presence
     - name: Build Sharing
-      run: CC=clang CXX=clang++ bazel build --verbose_failures --copt='-DGITHUB_BUILD' //sharing:nearby_sharing_service //sharing/certificates //sharing/contacts //sharing/local_device_data //sharing/proto/... //sharing/internal/public:nearby_context //sharing/common:all //sharing/scheduling //sharing/fast_initiation:nearby_fast_initiation //sharing/analytics
+      run: CC=clang-15 CXX=clang-15++ bazel build --verbose_failures --copt='-DGITHUB_BUILD' //sharing:nearby_sharing_service //sharing/certificates //sharing/contacts //sharing/local_device_data //sharing/proto/... //sharing/internal/public:nearby_context //sharing/common:all //sharing/scheduling //sharing/fast_initiation:nearby_fast_initiation //sharing/analytics
 
   build-rust-linux:
     name: Build Rust on Linux
@@ -77,4 +77,4 @@ jobs:
       run:  cargo test --manifest-path fastpair/rust/bluetooth/Cargo.toml
     - name: Build Fast Pair
       run:  cargo test --manifest-path fastpair/rust/demo/rust/Cargo.toml
-  
+  

.gitignore

@@ -52,4 +52,7 @@ Carthage/Build
 .idea
 
 # Rust
-Cargo.lock
+Cargo.lock
+
+# Bazel
+bazel-*

MODULE.bazel

@@ -1,11 +1,41 @@
 bazel_dep(name = "platforms", version = "0.0.8")
 bazel_dep(name = "rules_cc", version = "0.0.9")
+bazel_dep(name = "rules_rust", version = "0.42.1")
+bazel_dep(name = "bazel_skylib", version = "1.5.0")
 
 bazel_dep(name = "abseil-cpp", version = "20240116.1", repo_name = "com_google_absl")
 bazel_dep(name = "protobuf", version = "21.7", repo_name = "com_google_protobuf")
 bazel_dep(name = "googletest", version = "1.14.0", repo_name = "com_google_googletest")
 bazel_dep(name = "boringssl", version = "0.0.0-20240126-22d349c")
 
+git_repository = use_repo_rule("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
+git_repository(
+    name = "beto-core",
+    remote = "https://beto-core.googlesource.com/beto-core",
+    commit = "415bd032561d078720642d52e28fd3bc9d5155d4",
+)
+
+rust = use_extension("@rules_rust//rust:extensions.bzl", "rust")
+rust.toolchain(
+    edition = "2021",
+    versions = ["1.77.1"],
+)
+use_repo(rust, "rust_toolchains")
+register_toolchains("@rust_toolchains//:all")
+
+crate = use_extension(
+    "@rules_rust//crate_universe:extension.bzl",
+    "crate",
+)
+crate.from_cargo(
+    name = "crate_index",
+    cargo_lockfile = "@beto-core//:bazel_placeholder/Cargo.lock",
+    manifests = [
+        "@beto-core//:bazel_placeholder/Cargo.toml",
+    ],
+)
+use_repo(crate, "crate_index")
+
 http_archive = use_repo_rule("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
@@ -59,7 +89,6 @@ http_archive(
     strip_prefix = "nisaba-main",
 )
 
-
 # -------------------------------------------------------------------------
 # Protocol buffer matches (should be part of gmock and gtest, but not yet):
 #   https://github.com/inazarenko/protobuf-matchers