Bazel 示例

环境

C++ 11
Bazel 6.2.1
Java 11
MacOs(Clion) & Debian

开始

定义一个 WORKSPACE 文件，主要是申明一下项目的依赖关系

# 项目名称
workspace(name = "bazel_demo")

# init project dep
load("//:project_deps.bzl", "project_dependencies")

project_dependencies()

# init protobuf dep
# https://github.com/bazelbuild/rules_proto/releases/tag/4.0.0
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "rules_proto",
    sha256 = "66bfdf8782796239d3875d37e7de19b1d94301e8972b3cbd2446b332429b4df1",
    strip_prefix = "rules_proto-4.0.0",
    urls = [
        "https://mirror.bazel.build/github.com/bazelbuild/rules_proto/archive/refs/tags/4.0.0.tar.gz",
        "https://github.com/bazelbuild/rules_proto/archive/refs/tags/4.0.0.tar.gz",
    ],
)

load("@rules_proto//proto:repositories.bzl", "rules_proto_dependencies", "rules_proto_toolchains")

rules_proto_dependencies()

rules_proto_toolchains()

定义 BUILD 文件

load("@rules_cc//cc:defs.bzl", "cc_binary")

# main: 表示这个目标的名称
# src: 表示源文件
# deps: 表示依赖
cc_binary(
    name = "main",
    srcs = [
        "main.cpp",
    ],
    deps = [
        "//src/model",  # or "//src/model:model"
        "//src/utils",
        "@com_google_absl//absl/strings",
        "@com_google_absl//absl/strings:str_format",
    ],
)

编译Protobuf

➜  bazel_demo git:(master) ✗ tree -L 2 src/model/
src/model/
├── BUILD
├── common.proto
└── model.proto

注意PB include 是基于项目根路径进行引用

BUILD 文件

load("@rules_proto//proto:defs.bzl", "proto_library")

# 定义pb文件
proto_library(
    name = "model_proto",
    srcs = [
        "common.proto",
        "model.proto",
    ],
    deps = [
        "@com_google_protobuf//:any_proto",
    ],
)

# 编译cpp文件
cc_proto_library(
    name = "model",
    visibility = ["//visibility:public"],
    deps = [":model_proto"],
)

编译

➜  bazel_demo git:(master) ✗ bazel build //:main
INFO: Analyzed target //:main (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
Target //:main up-to-date:
  bazel-bin/main
INFO: Elapsed time: 0.193s, Critical Path: 0.01s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action

使用

http_archive https://bazel.build/rules/lib/repo/http#http_archive

http_archive(
	name = "com_google_absl",  # namespace name
	urls = ["https://github.com/abseil/abseil-cpp/archive/refs/tags/20220623.1.tar.gz"],  # 下载地址
	strip_prefix = "abseil-cpp-20220623.1",
	sha256 = "91ac87d30cc6d79f9ab974c51874a704de9c2647c40f6932597329a282217ba8",  # 下载文件的sha256，这个你不写也行
)

我觉得大家比较疑惑的是 strip_prefix，本质上就是因为我们下载的这些依赖文件吧，解压出来的路径有问题，需要移除掉有问题的前缀路径，最终需要此路径可以查找到WORKSPACE 文件

# 1. 下载
wget https://github.com/abseil/abseil-cpp/archive/refs/tags/20220623.1.tar.gz
# 2. 解压
tar -zxvf 20220623.1.tar.gz
# 3. http_archive 需要寻找解压文件的 WORKSPACE 文件, 因此需要 strip_prefix `abseil-cpp-20220623.1`
➜  software ls -al  abseil-cpp-20220623.1 | grep 'WORKSPACE'
-rw-r--r--  1 bytedance staff  2556  9  1  2022 WORKSPACE

proto_library https://docs.bazel.build/versions/master/be/protocol-buffer.html#proto_library

一些问题

Bazel 的进阶资料特别少，只能看官方文档了，以及参考一些开源项目的实践
开发者工具的话，这里也就只能用 clion 了，但是不太友好感觉
include 的问题，bazel里大部分都是源码构建，所以基本上需要使用: include "xxx" , 具体可以看 https://stackoverflow.com/questions/21593/what-is-the-difference-between-include-filename-and-include-filename
限制bazel构建版本: .bazelversion 文件填入版本
bazel构建配置: .bazelrc 文件填入构建配置

Anthony-Dong/bazel_demo

Bazel 示例

环境

开始

使用

一些问题