如何使用 shell 脚本在后续 Bazel 构建目标之前生成输出文件

Question

我有一些使用 shell 脚本构建的 protobuf 文件，如下所示：

proto.sh

#!/usr/bin/env bash

rm -rf ./proto-out
mkdir -p proto-out
protoc -Iproto --cpp_out=./proto-out ./proto/*.proto

但是我不知道如何在我的 BUILD 文件中获取输出 c++ 类和 headers。稍后我还需要能够在其他依赖库中使用 headers。我试过像这样的 genrule:

genrule(
    name = "proto-build",
    srcs = glob(["proto/*.proto"]),
    outs = [
        "proto-out/point.pb.h",
        "proto-out/point-geodetic.pb.h",
        "proto-out/point-ned.pb.h",
        "proto-out/point.pb.cc",
        "proto-out/point-geodetic.pb.cc",
        "proto-out/point-ned.pb.cc",
    ],
    cmd = "$(location proto.sh)",
    tools = ["proto.sh"],
    visibility = ["//visibility:public"],
)

cc_library(
    name = "protobuf-common",
    srcs = [
        "proto-out/point.pb.cc",
        "proto-out/point-geodetic.pb.cc",
        "proto-out/point-ned.pb.cc",
    ],
    hdrs = [
        "proto-out/point.pb.h",
        "proto-out/point-geodetic.pb.h",
        "proto-out/point-ned.pb.h",
    ],
    copts = ["--std=c++17"],
    data = [":proto"],
    includes = ["proto-out"],
    visibility = ["//visibility:public"],
)

但是执行此操作从来没有任何输出，cc_library 构建当然会失败。这是我第一天在我的团队中评估 Bazel 作为 CMake 的潜在替代品，因此我们将不胜感激。

谢谢

Answer 1

虽然您肯定可以使 genrule + cc_library 方法起作用，但有一些 proto 规则集可以为您完成所有这些工作：

cc_library(
    name = "your_code",
    srcs = ["your_code.cc"],
    deps = [":foo_cc_proto"],
)

cc_proto_library(
    name = "foo_cc_proto",
    deps = [":foo_proto"],
)

proto_library(
    name = "foo_proto",
)

参见：

https://bazel-contrib.github.io/SIG-rules-authors/proto-grpc.html

https://docs.bazel.build/versions/main/be/c-cpp.html#cc_proto_library

https://github.com/bazelbuild/rules_proto

https://github.com/bazelbuild/bazel/blob/45f462893df4d55cee19c05ab01e051e229597a3/src/main/protobuf/BUILD#L172-L175

如何使用 shell 脚本在后续 Bazel 构建目标之前生成输出文件

How to use shell script that generates output files prior to subsequent Bazel build targets

bazel

bazel-cpp