使用 Bazel 构建 OpenCV 代码 [英] Building OpenCV code using Bazel

问题描述

使用 Bazel 构建使用 OpenCV 库的 C++ 代码的最佳方法是什么?即，BUILD 规则是什么样的?

What is the best way to build C++ code that uses the OpenCV library using Bazel? I.e., what would the BUILD rules look like?

Bazel.io 有 外部依赖的文档，但不是很清楚.

Bazel.io has docs for external dependencies but it's not very clear.

推荐答案

有几个选项.最简单的方法可能是按照 OpenCV 站点推荐的方式在本地安装:

There are a couple of options. The easiest way is probably to install locally in the way the OpenCV site recommends:

git clone https://github.com/Itseez/opencv.git
cd opencv/
mkdir build install
cd build
cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/path/to/opencv/install ..
make install

然后将以下内容添加到您的 WORKSPACE 文件中:

Then add the following to your WORKSPACE file:

new_local_repository(
    name = "opencv",
    path = "/path/to/opencv/install",
    build_file = "opencv.BUILD",
)

在与 WORKSPACE 相同的目录中使用以下内容创建 opencv.BUILD:

Create opencv.BUILD in the same directory as WORKSPACE with the following:

cc_library(
    name = "opencv",
    srcs = glob(["lib/*.so*"]),
    hdrs = glob(["include/**/*.hpp"]),
    includes = ["include"],
    visibility = ["//visibility:public"], 
    linkstatic = 1,
)

那么你的代码就可以依赖@opencv//:opencv来链接lib/下的.so，并引用include/下的头文件.

Then your code can depend on @opencv//:opencv to link in the .so's under lib/ and reference the headers under include/.

然而，这不是很便携.如果您想要一个可移植的解决方案(并且您感觉雄心勃勃)，您可以将 OpenCV git repo 添加到您的工作区并下载 &建立它.类似的东西:

However, this isn't very portable. If you want a portable solution (and you're feeling ambitious), you could add the OpenCV git repo to your workspace and download & build it. Something like:

# WORKSPACE
new_git_repository(
    name = "opencv",
    remote = "https://github.com/Itseez/opencv.git",
    build_file = "opencv.BUILD",
    tag = "3.1.0",
)

并使 opencv.BUILD 类似于:

And make opencv.BUILD something like:

cc_library(
    name = "core",
    visibility = ["//visibility:public"],
    srcs = glob(["modules/core/src/**/*.cpp"]),
    hdrs = glob([
        "modules/core/src/**/*.hpp", 
        "modules/core/include/**/*.hpp"]
    ) + [":module-includes"],
)

genrule(
    name = "module-includes",
    cmd = "echo '#define HAVE_OPENCV_CORE' > $@",
    outs = ["opencv2/opencv_modules.hpp"],
)

...

那么你的代码可以依赖于更具体的目标，例如，@opencv//:core.

Then your code could depend on more specific targets, e.g., @opencv//:core.

作为第三种选择，您在 WORKSPACE 文件中同时声明 cmake 和 OpenCV，并使用 genrule 从 Bazel 中在 OpenCV 上运行 cmake.

As a third option, you declare both cmake and OpenCV in your WORKSPACE file and use a genrule to run cmake on OpenCV from within Bazel.

这篇关于使用 Bazel 构建 OpenCV 代码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！