bzl/rules.bzl

def _copy_go_binary_impl(ctx):
    output = ctx.actions.declare_file(ctx.label.name)
    for f in ctx.attr.src.files.to_list():
        # go_binary rules have two outputs, a library and the binary itself.
        # The following is a horrible hack to avoid copying the library.
        if f.path.endswith(".a"):
            continue
        ctx.actions.run_shell(
            inputs = [f],
            outputs = [output],
            mnemonic = "CopyGoBinary",
            command = "mkdir -p %s && cp %s %s" % (output.dirname, f.path, output.path),
        )
        return [DefaultInfo(executable = output)]

copy_go_binary = rule(
    implementation = _copy_go_binary_impl,
    attrs = {
        "src": attr.label(mandatory = True, allow_files = True),
    },
    executable = True,
)