alternate python rez package

package.py

name = "python"

version = "3.8.6"

authors = [
    "Guido van Rossum"
]

description = \
    """
    The Python programming language.
    """

requires = [
    'zlib-1.2.11',
]
private_build_requires = [
    'gcc',
    'cmake-3',
    #'openssl-1.1.1d'
]

@early()
def pyver():
    pylibvers = {'2.7': '2.7', '3.6': '3.6m', '3.7': '3.7m', '3.8': '3.8', '3.9':'3.9'}
    return pylibvers['.'.join(str(version).split('.')[0:2])] #[str(i) for i in [this.version.major, this.version.minor]])]

@early()
def variants():
    from rez.package_py_utils import expand_requires
    requires = ["platform-**", "arch-**"]#, "os-**"]
    return [expand_requires(*requires)]


@early()
def tools():
    # conditionally enumerate python 2 / 3 tools
    maj, mnr = this.version.split('.')[0:2]
    pyver = '.'.join([maj, mnr])
    all_vers = ['python{0}', 'python{0}-config', 'pydoc{0}', 'pip{0}']
    py2_only = ['smtpd.py']
    py3_only = ['pyenv', 'idle3']
    tools = py2_only if int(maj) < 3 else py3_only + ['idle']
    variants = ['', maj, pyver]
    for tool in all_vers:
        for variant in variants:
            tools.append(tool.format(variant))
    return tools + ['2to3', 'idle']



@early()
def uuid():
    import uuid
    return str(uuid.uuid5(uuid.NAMESPACE_DNS, name))


def pre_build_commands():
    #pyver = ".".join([str(i) for i in [this.version.major, this.version.minor, this.version.patch]])
    pyver = str(this.version)
    url = "http://www.python.org/ftp/python/%s/Python-%s.tgz" % (pyver, pyver)
    env.CFLAGS = " ".join(["-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2",
                          "-fexceptions -fstack-protector-strong",
                          "--param=ssp-buffer-size=4 -grecord-gcc-switches",
                          "-m64 -mtune=generic -D_GNU_SOURCE",
                          "-fPIC -fwrapv $CFLAGS"])
    env.LDFLAGS = "-Wl,-rpath,$REZ_BUILD_INSTALL_PATH/lib $LDFLAGS"
    config_opt = " ".join(["--prefix=$REZ_BUILD_INSTALL_PATH",
                          "--enable-ipv6",
                          "--enable-shared",
                          "--enable-unicode=ucs4",
                          "--with-dbmliborder=gdbm:ndbm:bdb",
                          "--with-system-expat",
                          "--with-system-ffi",
                          "--with-ensurepip",
                          "--with-computed-gotos=yes",
                          "--enable-optimizations",
                          #"--enable-loadable-sqlite-extensions",
                          #"--with-dtrace",
                          #"--with-valgrind",
                          #"--build=x86-64-redhat-linux-gnu ",
                          #"--host=x86_64-redhat-linux-gnu ",
                          #"--without-ensurepip ",
			              #"--enable-universalsdk",
    ])
    prefix = '$REZ_BUILD_INSTALL_PATH'
    config_cmd =  './configure %s' % config_opt
    link_cmd_cfg = 'ln -sfv python%s-config %s/bin/python-config' % (pyver.split('.')[0], prefix)
    download_cmd = 'wget %s' % url
    def link_cmd(exe): return 'ln -sfv {0}%s %s/bin/{0}'.format(exe) % (pyver.split('.')[0], prefix) if int(pyver.split('.')[0]) > 2 else ''
    
    env.REZ_BUILD_DOWNLOAD_CMD = download_cmd
    env.REZ_BUILD_UNPACK_CMD = 'tar -xvf Python*.tgz --strip 1'
    
    env.REZ_BUILD_CONFIGURE_CMD = config_cmd
    env.REZ_BUILD_MAKE_CMD = 'make install -j$REZ_BUILD_THREAD_COUNT VERBOSE=1'
    env.REZ_BUILD_LINK_CMD_0 = link_cmd('python')
    env.REZ_BUILD_LINK_CMD_1 = link_cmd('idle')
    env.REZ_BUILD_LINK_CMD_2 = link_cmd('pydoc')
    env.REZ_BUILD_LINK_CMD_3 = link_cmd('pip')
    env.REZ_BUILD_LINK_CMD_4 = link_cmd_cfg


build_command = """
$REZ_BUILD_DOWNLOAD_CMD
$REZ_BUILD_UNPACK_CMD
$REZ_BUILD_CONFIGURE_CMD
$REZ_BUILD_MAKE_CMD
$REZ_BUILD_LINK_CMD_0
$REZ_BUILD_LINK_CMD_1
$REZ_BUILD_LINK_CMD_2
$REZ_BUILD_LINK_CMD_3
#mkdir $REZ_BUILD_INSTALL_PATH/cmake
#cp {root}/python.cmake $REZ_BUILD_INSTALL_PATH/cmake
"""

def pre_commands():
    env.PYTHONHOME.unset()

def commands():
    env.PATH.prepend("{root}/bin")
    env.LD_LIBRARY_PATH.prepend("{root}/lib")

    if system.platform in ['osx']:
        env.DYLD_LIBRARY_PATH.prepend("{root}/lib")
        py_config = 'config-%s-%s' % (this.pyver, 'darwin')
        py_lib = '{root}/lib/lib%s.dylib' % this.pyver

    elif system.platform in ['linux']:
        py_config = 'config-%s-%s' % (this.pyver, 'x86_64-linux-gnu')
        py_lib = '{root}/lib/lib%s.so.1.0' % this.pyver
        
    else:
        if building:  # todo: support windows
            echo('python rez package - unsupported platform: %s' % system.platform)
            py_lib = None
            py_config = None

    if building:
        maj_min = '.'.join([str(i) for i in [this.version.major, this.version.minor]])
        env.PYTHONUSERBASE = '$REZ_BUILD_INSTALL_PATH'
        env.PYTHON_INCLUDE_DIRS = '{root}/include/python%s' % this.pyver
        env.PYTHON_EXECUTABLE = '{root}/bin/python%s' % this.pyver
        env.PYTHONEXECUTABLE = '{root}/bin/python%s' % this.pyver
        env.CMAKE_MODULE_PATH.prepend('{root}/cmake')
        env.PKG_CONFIG_PATH.prepend('{root}/include/pkgconfig')
        env.LDFLAGS = '-L{root}/lib -Wl,-rpath,{root}/lib $LDFLAGS'
        env.CFLAGS = '-I{root}/include/python%s $CFLAGS' % this.pyver
        env.CXXFLAGS = '-I{root}/include/python%s $CXXFLAGS' % this.pyver
        env.CPPFLAGS = '-I{root}/include/python%s $CPPFLAGS' % this.pyver
        if py_lib:
            env.PYTHON_LIBRARY = py_lib
            env.PYTHON_LIBRARIES = '{root}/lib/python%s/%s/libpython%s.a' % (maj_min, py_config, this.pyver)