Bazel Link .so libraries located in a completely different, very remote folder - c++

Question

Folks,
I am trying to link .h and static libraries into my tensorflow program. My headers are in
/usr/local/include/lcm
And static/shared libraries (.so, etc.) in
/usr/local/lib
But Bazel complains they don't exist, or that it cannot find them. Here is my code on my BUILD file:
package(default_visibility = ["//tensorflow:internal"])
licenses(["notice"]) # Apache 2.0
exports_files(["LICENSE"])
# LCM shared libraries path
cc_library(
name = "lcm_lib",
srcs = glob([
"*.so",
]),
copts = ["-L/usr/local/lib"],
linkopts = ["-pthread", "-shared"],
visibility = ["//visibility:public"],
)
# LCM header libraries path
cc_library(
name = "lcm_headers",
hdrs = glob([
"include/**/*.h",
]),
copts = ["-L/usr/local/include"],
linkopts = ["-pthread"],
visibility = ["//visibility:public"],
)
cc_binary(
name = "myProject",
srcs = [
"main.cc",
],
linkopts = ["-lm"],
deps = [
"//tensorflow/cc:cc_ops",
"//tensorflow/core:framework_internal",
"//tensorflow/core:tensorflow",
],
)
filegroup(
name = "all_files",
srcs = glob(
["**/*"],
exclude = [
"**/METADATA",
"**/OWNERS",
"bin/**",
"gen/**",
],
),
visibility = ["//tensorflow:__subpackages__"],
)
If I remove LCM related code (from both BUILD and main.cc), then my program builds and runs. When I include LCM, then I get errors saying that lcm::LCM::~LCM() is undefined, and that it cannot find the liblcm.so.
Now, my non-tensorflow code (or the majority of my project) is running cmake, and LCM and the rest of the libraries I need (openCV, etc.) can be found. I use commands in my CMakeList.txt like:
# search path for LCM header files
set(LCM_IncludeSearchPaths
/usr/include/
/usr/local/include/
/opt/local/include
)
# search path for LCM static/dynamic libraries
set(LCM_LibrarySearchPaths
/usr/lib/
/usr/local/lib/
/opt/local/lib/
)
find_path(LCM_INCLUDE_DIR
NAMES lcm/lcm.h
HINTS ${LCM_IncludeSearchPaths}
)
FIND_LIBRARY(LCM_LIBS
NAMES lcm
HINTS ${LCM_LibrarySearchPaths}
PATH_SUFFIXES lib
)
And it all works. But it does not work for tensorflow and Bazel
Here are my build and WORKSPACE files, located in the same directory:
This is my touched WORKSPACE file:
# LCM static libraries
new_local_repository(
name = "lcm_libs",
# pkg-config --variable=libdir x11
path = "/usr/local/lib",
build_file_content = """
cc_library(
name = "liblcm",
srcs = ["liblcm.so"],
visibility = ["//visibility:public"],
)
""",
)
# LCM header files
new_local_repository(
name = "lcm_headers",
# pkg-config --variable=libdir x11
path = "/usr/local/include",
build_file_content = """
cc_library(
name = "lcm",
hdrs = glob([
"lcm/*.h", "lcm/*.hpp",
]),
visibility = ["//visibility:public"],
)
""",
)
# bind to a name to avoid using the "actual" format
#bind(
# name = "liblcm",
# actual = "#lcm_libs//:liblcm",
#)
#bind(
# name = "lcm",
# actual = "#lcm_headers//:lcm",
#)
#
And my BUILD:
# Description:
# Tensorflow C++ inference example for labeling images.
package(default_visibility = ["//tensorflow:internal"])
licenses(["notice"]) # Apache 2.0
exports_files(["LICENSE"])
cc_binary(
name = "facialFatigue",
srcs = [
"main.cc",
],
linkopts = ["-lm"],
deps = [
"//tensorflow/cc:cc_ops",
"//tensorflow/core:framework_internal",
"//tensorflow/core:tensorflow",
"#lcm_libs//:liblcm",
"#lcm_headers//:lcm",
],
)
filegroup(
name = "all_files",
srcs = glob(
["**/*"],
exclude = [
"**/METADATA",
"**/OWNERS",
"bin/**",
"gen/**",
],
),
visibility = ["//tensorflow:__subpackages__"],
)
Sorry for the long question :-(

Answer 1

Bazel executes action (in your case C++ compile action) in a sandbox, to ensure the hermeticity. This is needed to be correct when inputs of the action change. Therefore you have to tell Bazel about all the inputs, including the system ones.
But of course you can depend on system libraries, take a look at local_repository rule. You might also find this example in bazel-discuss# thread helpful.