feat: support bazel build for cpp bindings #107

zhaohaidao · 2025-12-21T07:23:20Z

Purpose

Linked issue: close #106

Brief change log

Tests

API and Format

Documentation

zhaohaidao · 2025-12-21T07:26:09Z

@luoyuxia Hi, yuxia. I added bazel build ability for cpp binding. PTAL if u have time.

Copilot

Pull request overview

This pull request adds Bazel build system support for the C++ bindings, providing an alternative to the existing CMake build system. The implementation enables users to build the fluss_cpp library and example binary using Bazel.

Key changes:

Added Bazel build configuration files (MODULE.bazel, BUILD.bazel, .bazelrc) for building C++ bindings
Introduced a ci.sh script to simplify common Bazel build operations
Updated .gitignore to exclude Bazel-generated files

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
bindings/cpp/ci.sh	Build automation script providing commands to compile, build examples, run examples, show outputs, and clean Bazel artifacts
bindings/cpp/MODULE.bazel	Bazel module definition declaring dependencies on rules_cc and platforms
bindings/cpp/BUILD.bazel	Core Bazel build rules defining genrule for cargo compilation, cc_library for the fluss_cpp library, and cc_binary for the example executable
bindings/cpp/.bazelrc	Bazel configuration file enabling BzlMod and defining debug build settings
bindings/cpp/.gitignore	Updated to ignore Bazel build outputs and generated files

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Copilot · 2025-12-21T07:44:43Z

bindings/cpp/MODULE.bazel

@@ -0,0 +1,7 @@
+module(


Missing Apache License header. All source files in Apache projects should include the standard Apache License header. Add the header at the beginning of the file using '#' comment syntax, similar to CMakeLists.txt or Cargo.toml.

Copilot · 2025-12-21T07:44:43Z

bindings/cpp/BUILD.bazel

@@ -0,0 +1,142 @@
+licenses(["notice"])


Missing Apache License header. All source files in Apache projects should include the standard Apache License header. Add the header at the beginning of the file using '#' comment syntax, similar to CMakeLists.txt or Cargo.toml.

Copilot · 2025-12-21T07:44:44Z

bindings/cpp/ci.sh

@@ -0,0 +1,85 @@
+#!/bin/bash
+
+set -xe 


Trailing whitespace after 'set -xe'. This should be 'set -xe' without the trailing space for consistency.

Copilot · 2025-12-21T07:44:44Z

bindings/cpp/ci.sh

+        exit 1
+        ;;
+esac
+


Blank line at the end of the file. While this is generally a minor style issue, it's inconsistent with typical bash script conventions. Consider removing this trailing blank line for consistency.

Suggested change

Copilot · 2025-12-21T07:44:44Z

bindings/cpp/BUILD.bazel

+        RUST_BRIDGE_DIR=$$CARGO_TARGET_DIR/cxxbridge/fluss-cpp/src
+        RUST_LIB=$$CARGO_TARGET_DIR/debug/libfluss_cpp.a


The hardcoded library name 'libfluss_cpp.a' doesn't match the expected output based on the Cargo package name 'fluss-cpp' (with hyphen). Cargo converts hyphens to underscores in library names, so this is correct. However, the cxxbridge path uses 'fluss-cpp' with a hyphen. This inconsistency between line 39 (using 'fluss-cpp') and line 40 (using 'fluss_cpp') is potentially confusing and error-prone. Verify that these paths are correct given Cargo's naming conventions.

Please check this suggestion.

Copilot · 2025-12-21T07:44:45Z

bindings/cpp/BUILD.bazel

+genrule(
+    name = "cargo_build_debug",
+    srcs = glob([
+        "src/**/*.rs",
+        "Cargo.toml",
+    ]),
+    outs = [
+        "rust_lib_debug.a",
+        "rust_bridge_cc.cc",
+        "rust_bridge_h.h",
+        "src/lib.rs.h",
+        "cxxbridge/rust/cxx.h",
+    ],
+    cmd = """
+        set -e
+        EXECROOT=$$(pwd)
+        OUTPUT_LIB=$(location rust_lib_debug.a)
+        OUTPUT_CC=$(location rust_bridge_cc.cc)
+        OUTPUT_H=$(location rust_bridge_h.h)
+        OUTPUT_SRC_H=$(location src/lib.rs.h)
+        OUTPUT_CXX_H=$(location cxxbridge/rust/cxx.h)
+        # Resolve real source path from sandbox symlink
+        SANDBOX_CARGO=$(location Cargo.toml)
+        REAL_CARGO=$$(readlink -f $$SANDBOX_CARGO 2>/dev/null || python3 -c "import os; print(os.path.realpath('$$SANDBOX_CARGO'))")
+        CARGO_DIR=$$(dirname $$REAL_CARGO)
+        # Find Cargo workspace root (fluss-rust directory, 2 levels up from bindings/cpp)
+        WORKSPACE_ROOT=$$(cd $$CARGO_DIR/../.. && pwd)
+        if [ ! -f $$WORKSPACE_ROOT/Cargo.toml ]; then
+            echo "Error: Cannot find workspace root Cargo.toml at $$WORKSPACE_ROOT" >&2
+            exit 1
+        fi
+        cd $$WORKSPACE_ROOT
+        cargo build --manifest-path $$CARGO_DIR/Cargo.toml
+        CARGO_TARGET_DIR=$$WORKSPACE_ROOT/target
+        RUST_BRIDGE_DIR=$$CARGO_TARGET_DIR/cxxbridge/fluss-cpp/src
+        RUST_LIB=$$CARGO_TARGET_DIR/debug/libfluss_cpp.a
+        if [ ! -f $$RUST_LIB ]; then
+            echo "Error: Rust library not found at $$RUST_LIB" >&2
+            exit 1
+        fi
+        if [ ! -f $$RUST_BRIDGE_DIR/lib.rs.cc ]; then
+            echo "Error: cxxbridge CC file not found at $$RUST_BRIDGE_DIR/lib.rs.cc" >&2
+            exit 1
+        fi
+        if [ ! -f $$RUST_BRIDGE_DIR/lib.rs.h ]; then
+            echo "Error: cxxbridge header file not found at $$RUST_BRIDGE_DIR/lib.rs.h" >&2
+            exit 1
+        fi
+        cd $$EXECROOT
+        mkdir -p $$(dirname $$OUTPUT_SRC_H) $$(dirname $$OUTPUT_CXX_H)
+        cp $$RUST_LIB $$OUTPUT_LIB || (echo "Failed to copy $$RUST_LIB to $$OUTPUT_LIB" >&2; exit 1)
+        cp $$RUST_BRIDGE_DIR/lib.rs.cc $$OUTPUT_CC || (echo "Failed to copy $$RUST_BRIDGE_DIR/lib.rs.cc to $$OUTPUT_CC" >&2; exit 1)
+        cp $$RUST_BRIDGE_DIR/lib.rs.h $$OUTPUT_H || (echo "Failed to copy $$RUST_BRIDGE_DIR/lib.rs.h to $$OUTPUT_H" >&2; exit 1)
+        cp $$RUST_BRIDGE_DIR/lib.rs.h $$OUTPUT_SRC_H || (echo "Failed to copy $$RUST_BRIDGE_DIR/lib.rs.h to $$OUTPUT_SRC_H" >&2; exit 1)
+        CXX_H_SOURCE=$$CARGO_TARGET_DIR/cxxbridge/rust/cxx.h
+        if [ ! -f $$CXX_H_SOURCE ] && [ ! -L $$CXX_H_SOURCE ]; then
+            echo "Error: cxx.h not found at $$CXX_H_SOURCE" >&2
+            exit 1
+        fi
+        cp -L $$CXX_H_SOURCE $$OUTPUT_CXX_H || (echo "Failed to copy $$CXX_H_SOURCE to $$OUTPUT_CXX_H" >&2; exit 1)
+    """,
+    message = "Building Rust library with cargo...",
+    local = 1,
+)


The genrule name 'cargo_build_debug' suggests this only builds debug variants, but there's no corresponding rule for release builds. This means users can only build debug binaries with Bazel, which limits flexibility compared to the CMake build that supports both debug and release configurations. Consider adding a configuration or additional genrule to support release builds.

the suggestion looks reasonable to me.

Copilot · 2025-12-21T07:44:46Z

bindings/cpp/BUILD.bazel

+    copts = [
+        "-std=c++17",
+        "-g3",
+        "-O0",
+        "-ggdb",
+        "-fno-omit-frame-pointer",
+        "-DDEBUG",
+    ],


Similar to the cc_library rule, debug compilation flags are hardcoded in the cc_binary rule. This prevents building optimized example binaries. Consider making these flags configurable to match the library's build configuration.

Copilot · 2025-12-21T07:44:46Z

bindings/cpp/BUILD.bazel

+    ],
+    visibility = ["//visibility:public"],
+)
+


Two trailing blank lines at the end of the file. Consider removing these extra blank lines for consistency with common style guidelines.

Suggested change

Copilot · 2025-12-21T07:44:46Z

bindings/cpp/MODULE.bazel

+
+bazel_dep(name = "rules_cc", version = "0.0.17")
+bazel_dep(name = "platforms", version = "0.0.10")
+


Trailing blank line at the end of the file. Consider removing this for consistency with Bazel style guidelines.

Suggested change

Copilot · 2025-12-21T07:44:46Z

bindings/cpp/.bazelrc

+build:debug --copt=-DDEBUG
+build:debug --strip=never
+build:debug --linkopt=-g
+


Trailing blank line at the end of the file. Consider removing this for consistency.

Suggested change

luoyuxia

@zhaohaidao Thanks for the pr. I have no much experience with bazel, but take care about the suggestion by copiot.

luoyuxia · 2025-12-21T09:14:22Z

bindings/cpp/.bazelrc

@@ -0,0 +1,15 @@
+# Bazel configuration for fluss-rust C++ bindings


luoyuxia · 2025-12-21T09:14:38Z

bindings/cpp/BUILD.bazel

@@ -0,0 +1,142 @@
+licenses(["notice"])


luoyuxia · 2025-12-21T09:15:20Z

bindings/cpp/BUILD.bazel

+        RUST_BRIDGE_DIR=$$CARGO_TARGET_DIR/cxxbridge/fluss-cpp/src
+        RUST_LIB=$$CARGO_TARGET_DIR/debug/libfluss_cpp.a


Please check this suggestion.

luoyuxia · 2025-12-21T09:16:08Z

bindings/cpp/BUILD.bazel

+genrule(
+    name = "cargo_build_debug",
+    srcs = glob([
+        "src/**/*.rs",
+        "Cargo.toml",
+    ]),
+    outs = [
+        "rust_lib_debug.a",
+        "rust_bridge_cc.cc",
+        "rust_bridge_h.h",
+        "src/lib.rs.h",
+        "cxxbridge/rust/cxx.h",
+    ],
+    cmd = """
+        set -e
+        EXECROOT=$$(pwd)
+        OUTPUT_LIB=$(location rust_lib_debug.a)
+        OUTPUT_CC=$(location rust_bridge_cc.cc)
+        OUTPUT_H=$(location rust_bridge_h.h)
+        OUTPUT_SRC_H=$(location src/lib.rs.h)
+        OUTPUT_CXX_H=$(location cxxbridge/rust/cxx.h)
+        # Resolve real source path from sandbox symlink
+        SANDBOX_CARGO=$(location Cargo.toml)
+        REAL_CARGO=$$(readlink -f $$SANDBOX_CARGO 2>/dev/null || python3 -c "import os; print(os.path.realpath('$$SANDBOX_CARGO'))")
+        CARGO_DIR=$$(dirname $$REAL_CARGO)
+        # Find Cargo workspace root (fluss-rust directory, 2 levels up from bindings/cpp)
+        WORKSPACE_ROOT=$$(cd $$CARGO_DIR/../.. && pwd)
+        if [ ! -f $$WORKSPACE_ROOT/Cargo.toml ]; then
+            echo "Error: Cannot find workspace root Cargo.toml at $$WORKSPACE_ROOT" >&2
+            exit 1
+        fi
+        cd $$WORKSPACE_ROOT
+        cargo build --manifest-path $$CARGO_DIR/Cargo.toml
+        CARGO_TARGET_DIR=$$WORKSPACE_ROOT/target
+        RUST_BRIDGE_DIR=$$CARGO_TARGET_DIR/cxxbridge/fluss-cpp/src
+        RUST_LIB=$$CARGO_TARGET_DIR/debug/libfluss_cpp.a
+        if [ ! -f $$RUST_LIB ]; then
+            echo "Error: Rust library not found at $$RUST_LIB" >&2
+            exit 1
+        fi
+        if [ ! -f $$RUST_BRIDGE_DIR/lib.rs.cc ]; then
+            echo "Error: cxxbridge CC file not found at $$RUST_BRIDGE_DIR/lib.rs.cc" >&2
+            exit 1
+        fi
+        if [ ! -f $$RUST_BRIDGE_DIR/lib.rs.h ]; then
+            echo "Error: cxxbridge header file not found at $$RUST_BRIDGE_DIR/lib.rs.h" >&2
+            exit 1
+        fi
+        cd $$EXECROOT
+        mkdir -p $$(dirname $$OUTPUT_SRC_H) $$(dirname $$OUTPUT_CXX_H)
+        cp $$RUST_LIB $$OUTPUT_LIB || (echo "Failed to copy $$RUST_LIB to $$OUTPUT_LIB" >&2; exit 1)
+        cp $$RUST_BRIDGE_DIR/lib.rs.cc $$OUTPUT_CC || (echo "Failed to copy $$RUST_BRIDGE_DIR/lib.rs.cc to $$OUTPUT_CC" >&2; exit 1)
+        cp $$RUST_BRIDGE_DIR/lib.rs.h $$OUTPUT_H || (echo "Failed to copy $$RUST_BRIDGE_DIR/lib.rs.h to $$OUTPUT_H" >&2; exit 1)
+        cp $$RUST_BRIDGE_DIR/lib.rs.h $$OUTPUT_SRC_H || (echo "Failed to copy $$RUST_BRIDGE_DIR/lib.rs.h to $$OUTPUT_SRC_H" >&2; exit 1)
+        CXX_H_SOURCE=$$CARGO_TARGET_DIR/cxxbridge/rust/cxx.h
+        if [ ! -f $$CXX_H_SOURCE ] && [ ! -L $$CXX_H_SOURCE ]; then
+            echo "Error: cxx.h not found at $$CXX_H_SOURCE" >&2
+            exit 1
+        fi
+        cp -L $$CXX_H_SOURCE $$OUTPUT_CXX_H || (echo "Failed to copy $$CXX_H_SOURCE to $$OUTPUT_CXX_H" >&2; exit 1)
+    """,
+    message = "Building Rust library with cargo...",
+    local = 1,
+)


the suggestion looks reasonable to me.

赵海源 added 6 commits December 20, 2025 20:36

support more cpp api

fe0e670

support bazel build

81ff6f6

address comments

93caae3

address comments

4f1e83a

Merge branch 'cpp-api' into bazel

43cf0f0

Merge remote-tracking branch 'forked/main' into bazel

a9e7e50

luoyuxia requested a review from Copilot December 21, 2025 07:41

Copilot started reviewing on behalf of luoyuxia December 21, 2025 07:41 View session

Copilot AI reviewed Dec 21, 2025

View reviewed changes

luoyuxia reviewed Dec 21, 2025

View reviewed changes

		RUST_BRIDGE_DIR=$$CARGO_TARGET_DIR/cxxbridge/fluss-cpp/src
		RUST_LIB=$$CARGO_TARGET_DIR/debug/libfluss_cpp.a


		bazel_dep(name = "rules_cc", version = "0.0.17")
		bazel_dep(name = "platforms", version = "0.0.10")

		@@ -0,0 +1,15 @@
		# Bazel configuration for fluss-rust C++ bindings

feat: support bazel build for cpp bindings #107

Are you sure you want to change the base?

feat: support bazel build for cpp bindings #107

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zhaohaidao commented Dec 21, 2025

Purpose

Brief change log

Tests

API and Format

Documentation

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zhaohaidao commented Dec 21, 2025

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