patch_venv.sh

#!/bin/bash

codeblock()
{
    if [ "-h" == "$1" ] || [ "--help" == "$1" ]; then 
        # Use codeblock to show the usage of codeblock, so you can use
        # codeblock while you codeblock.
        echo "$(codeblock '
            Unindents code before its executed so you can maintain a pretty
            indentation in your code file. Multiline strings simply begin  
            with 
                "$(codeblock "
            and end with 
                ")"

            Example:
               echo "$(codeblock "
                    a long
                    multiline string.
                    this is the last line that will be considered.
                    ")"
        ')"
    else
        # Prevents python indentation errors in bash
        #python -c "from textwrap import dedent; print(dedent('''$1''').strip('\n'))"
        echo "$1" | python -c "import sys; from textwrap import dedent; print(dedent(sys.stdin.read()).strip('\n'))"
    fi
}


patch_venv_with_libs(){
    # References:
    # https://github.com/pypa/virtualenv/pull/1045
    ACTIVATE_SCRIPT=$VIRTUAL_ENV/bin/activate

    # apply the patch 
    python -c "$(codeblock "
        import textwrap
        text = open('$ACTIVATE_SCRIPT', 'r').read()
        lines = text.splitlines(True)

        def absindent(text, prefix=''):
            text = textwrap.dedent(text).lstrip()
            text = prefix + prefix.join(text.splitlines(True))
            return text.splitlines(True)

        if len(lines) > 80:
            # hacky way of preventing extra patches
            print('file is already patched')
        else:
            print('patching')
            new_lines = []
            for old_lineno, line in enumerate(lines, start=1):
                new_lines.append(line)
                if old_lineno == 10:
                    new_lines.extend(absindent('''
                            C_INCLUDE_PATH=\"\$_OLD_C_INCLUDE_PATH\"
                            LD_LIBRARY_PATH=\"\$_OLD_VIRTUAL_LD_LIBRARY_PATH\"

                        ''', ' ' * 8))
                elif old_lineno == 11:
                    new_lines.extend(absindent('''
                            export C_INCLUDE_PATH
                            export LD_LIBRARY_PATH

                            unset _OLD_C_INCLUDE_PATH
                            unset _OLD_VIRTUAL_LD_LIBRARY_PATH
                        ''', ' ' * 8))
                elif old_lineno == 46:
                    new_lines.extend(absindent('''
                            _OLD_C_INCLUDE_PATH=\"\$C_INCLUDE_PATH\"
                            _OLD_VIRTUAL_LD_LIBRARY_PATH=\"\$LD_LIBRARY_PATH\"

                        '''))
                elif old_lineno == 47:
                    new_lines.extend(absindent('''
                            C_INCLUDE_PATH=\"\$C_INCLUDE_PATH/include:\$C_INCLUDE_PATH\"
                            LD_LIBRARY_PATH=\"\$VIRTUAL_ENV/lib:\$LD_LIBRARY_PATH\"

                        '''))
                elif old_lineno == 48:
                    new_lines.extend(absindent('''
                            export C_INCLUDE_PATH
                            export LD_LIBRARY_PATH
                        '''))
            new_text = ''.join(new_lines)
            open('$ACTIVATE_SCRIPT', 'w').write(new_text)
    ")"
}

patch_venv_with_libs