Accessing environment variables in genrules

[Indigo Orton]

Hi,

I'm writing some genrules that access scripts that rely on System environment variables. I can't find anything in the docs on how to allow (or pass) genrules access to the system environment variables.

Is this supported? If so how do I do it?

Thanks

Indigo

[Han-Wen Nienhuys]

The environment of rules is standardized to increase reproducibilty.

One way of addressing this is to set environment variables explicitly, eg.

genrules(name = "blah",
cmd= "LD_LIBRARY_PATH=/usr/local/lib ; FOO_CONFIG=/opt/foo/etc ; " +
"/opt/foo/bin/foo")

another strategy is to have a separate script which will write the
relevant variables into a source file, and then run the source file

genrules(name = "blah",
cmd= "source $(location //:common.sh) ; /opt/foo/bin/foo",
data = "//:common.sh")

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--
Han-Wen Nienhuys
Google Munich
han...@google.com

[Indigo Orton]

Thanks Han-Wen, that works for a few of the variables (e.g. sdk-location variables), however it doesn't help for things like CMake variables.

As much as I hate it, I currently use CMake to compile my JNI library (it is the easiest way I've found with generated code, and I was using CMake before so it wasn't hard to bring into Bazel). When I try to configure from the CMakeLists.txt I get errors regarding CMake compiler flags/variables (specifically "CMAKE_C_COMPILER_ENV_VAR" and "CMAKE_CXX_COMPILER_ENV_VAR"). When I run the same commands outside of the genrule it all works fine, so it is the environment.

Is there a better way to do jni compilation (aside from an Android.mk and storing all jni sources in a jni folder in an Android project)? Will imagine this will be supported in the mid year release? What can I do until then?

[Ulf Adams]

Well, cc_library and friends are intended to compile C++ code. If you want to build for Android, it shouldn't be too tricky to write a corresponding CROSSTOOL file. Is this 'only' an Android app or do you also have other code in your repo?

To view this discussion on the web visit https://groups.google.com/d/msgid/bazel-discuss/abeebb97-1563-435f-98fa-2997889f30e6%40googlegroups.com.

[Indigo Orton]

Lots of other code. We have backend, web, Android and iOS (Android and iOS share the C++ code). I'll look into building a CROSSTOOL, but it would be nice to have someway of bringing these kind of environment variables.