Help adding a dependency

[Andy John]

Hi there,

  I am trying to add libcbor as a dependency.

This is a C++ project that uses cmake, It lives here:

https://github.com/PJK/libcbor

I see I can include a BUILD_libcbor file, which will be overlaid on the downloaded

code. But there is a cmake step that creates a .h file, based on what platform

you are running on. After that, I think it's a straightforward c library.

Can I include additional files to overlay, and just include the .h file I would end up with?

Can Bazel run cmake? Should I just pre-compile the library and include the .so?

Should I try to get a Bazel BUILD file included into the project?

Thanks for any help,

Andy

[Gregg Reynolds]

Bazel can run cmake.  See https://github.com/bazelbuild/rules_foreign_cc

Gregg

--
You received this message because you are subscribed to the Google Groups "bazel-discuss" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bazel-discus...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/bazel-discuss/eaffb512-e843-473e-ae4e-2b65f84e846en%40googlegroups.com.

[Gregg Reynolds]

On Wed, Jul 7, 2021 at 4:00 PM Andy John <an...@google.com> wrote:

Thanks!

I have it running both cmake and make.

But, the cmake step builds the makefiles. Then I need the make step to run INSIDE the cmake's output.

It's running on its own copy of the code, so no makefiles are present.

Is there a way to have the cmake step export the entire tree as output, and have make use that as it's source?

I see there are lib-out, header-out etc... options....

Dunno off the top of my head, I'd have to see the code.  Is it online somewhere?v  In general, there's always a way, but some ways are more painful than others, heh.

Can you use `exports_files` and/or filegroups? 

[Andy John]

The library I am trying to include is "libcbor", it's here:

https://github.com/PJK/libcbor/blob/master/README.md

Here are the manual steps that I want to re-create in Bazel:

wget https://github.com/PJK/libcbor/archive/refs/tags/v0.8.0.zip

unzip v0.8.0.zip

cd libcbor-0.8.0

cmake -DCMAKE_BUILD_TYPE=Release -DCBOR_CUSTOM_ALLOC=ON

make

output I care about is:

  src/libcor.a

  src/libcor.h

  src/cbor/*.h

I know everything up to the cmake step is OK.

I *think* the cmake step is OK.

The make step is failing - no Makefiles.

Here's my make rule:

make(

    name = "cbor",

    targets = ["all"],  # Don't need this? all is default?

    lib_source = ":cbor_cmake", # This is the cbor rule, to see it's files?

    out_include_dir = "src",

    out_static_libs = ["src/libcbor.a"],

    deps = [":cbor_cmake"],  # Make sure cmake runs first.

    visibility = ["//visibility:public"],

)

Thanks,

Andy

[Andy John]

Thanks, 

  I got cmake and make working.

But I need the make command to run inside the modified source tree that cmake created (where it wrote the Makefiles).

Is there a way to do this?

Or is there a way to tell the cmake rule to kick off a make step after?

The cmake step is only generating 3 Makefiles - if I copy just those 3 files over to a fresh tree

it builds with Make. Can I just do this via Bazel?

Thanks again,

Andy

[Andy John]

Thanks!

I have it running both cmake and make.

But, the cmake step builds the makefiles. Then I need the make step to run INSIDE the cmake's output.

It's running on its own copy of the code, so no makefiles are present.

Is there a way to have the cmake step export the entire tree as output, and have make use that as it's source?

I see there are lib-out, header-out etc... options....

Thanks again,

Andy

--

Andrew John, Google Fonts

[Alex Garcia]

That was added recently, look at the python build example on master, it exposes a full dir as the output.

Alexandre Garcia Mayans

To view this discussion on the web visit https://groups.google.com/d/msgid/bazel-discuss/CAEQeahDd6K-Q%3Dw9yFgHwmwrJhg5j0F%2Bw_mvNiLKpDS461dvpbg%40mail.gmail.com.

[Andy John]

I tried, and the cmake rule does not allow exports_files.

On Wednesday, July 7, 2021 at 2:49:18 PM UTC-7 d...@mobileink.com wrote:

[Andy John]

Thanks! 

I sent a PR for a minor fix.

I think this will do exactly what I need.

Andy

[Andy John]

When you specify out_data_dirs using a glob(**), does it run the glob after running cmake, or before?

I need it to be after.

The next step is not seeing the generated files.

Andy

[Andy John]

Or maybe I'm using the output incorrectly?

My cmake rule is called "cbor_cmake".

In my make rule, I am using:

      lib_source = ":cbor_cmake",

Is that all I need to do?

Andy

[Andy John]

I've been told that the cmake rule actually does 3 steps, cmake, build and install.

So it should be running the make step for me.

I have tested this on the command line, and it does work.

Here's my cmake rule, can anyone help me figure out why it's not doing the build step?

filegroup(

    name = "srcs",

    srcs = glob(["**"]),

    visibility = ["//visibility:private"],

)

cmake(

    name = "cbor",

    cache_entries = {

        "CMAKE_MACOSX_RPATH": "True",

        "CMAKE_BUILD_TYPE": "Release",

        "CBOR_CUSTOM_ALLOC": "ON",

    },

    lib_source = ":srcs",

    out_lib_dir = "src",

    out_static_libs = ["libcbor.a"],

    visibility = ["//visibility:public"],

) 

[Gregg Reynolds]

On Thu, Jul 8, 2021 at 6:42 PM 'Andy John' via bazel-discuss <bazel-...@googlegroups.com> wrote:

I've been told that the cmake rule actually does 3 steps, cmake, build and install.

So it should be running the make step for me.

I have tested this on the command line, and it does work.

Here's my cmake rule, can anyone help me figure out why it's not doing the build step?

filegroup(

    name = "srcs",

    srcs = glob(["**"]),

    visibility = ["//visibility:private"],

)

cmake(

    name = "cbor",

    cache_entries = {

        "CMAKE_MACOSX_RPATH": "True",

        "CMAKE_BUILD_TYPE": "Release",

        "CBOR_CUSTOM_ALLOC": "ON",

    },

    lib_source = ":srcs",

    out_lib_dir = "src",

    out_static_libs = ["libcbor.a"],

    visibility = ["//visibility:public"],

) 

Try it with just the defaults for out_lib_src and out_static_libs, and no cache_entries?  In the past I've sometimes found that setting such attribs messes things up.