I have a few protobuf files that I'm building with a shell script like so:
proto.sh
#!/usr/bin/env bash
rm -rf ./proto-out
mkdir -p proto-out
protoc -Iproto --cpp_out=./proto-out ./proto/*.proto
However I'm at a loss of what to do in my BUILD file to get the output c++ classes and headers. I'll need to be able to utilize the headers in other dependent libraries later as well. I've tried with genrule like so:
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"],
)
but there is never any output from the execution of this and the cc_library build of course fails. This is my first day evaluating Bazel as a potential replacement for CMake on my team so any help would be appreciated.
Thanks
While you can surely make the genrule + cc_library approach work, there are rulesets for proto that does all this for you:
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",
)
See:
https://bazel-contrib.github.io/SIG-rules-authors/proto-grpc.html
https://docs.bazel.build/versions/main/be/c-cpp.html#cc_proto_library