j2

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import json
import os
import jinja2

EXTENSIONS = ["jinja2.ext.loopcontrols", "jinja2.ext.debug"]
NO_CLOBBER = False
PICO8_MODE = False

def render_template(template_path, input_data, out_path):
    exopts = {}
    if PICO8_MODE:
        exopts = {
            "variable_start_string": '"{{',
            "variable_end_string": '}}"',
            "line_statement_prefix": "--%"
        }
    print("Rendering template '{}' to '{}'".format(template_path, out_path))
    env = jinja2.Environment(
        loader=jinja2.FileSystemLoader(os.path.dirname(template_path)),
        extensions=EXTENSIONS,
        keep_trailing_newline=True,
        **exopts
    )

    # Add environ global
    os.environ["UID"] = str(os.getuid())
    env.globals["environ"] = lambda key: str(os.environ.get(key))
    env.globals["get_context"] = lambda: input_data

    return env.get_template(os.path.basename(template_path)).render(input_data)


def auto_render_template(file_path, input_data):
    out_path, dotj2 = os.path.splitext(file_path)
    if dotj2 != ".j2":
        raise ValueError("File '{}' is not a jinja2 template ending with .j2".format(file_path))
    if os.path.isfile(out_path) and NO_CLOBBER:
        raise IOError("File exists: '{}' and no-clobber is {}.".format(out_path, NO_CLOBBER))
    with open(out_path, 'wb') as fp:
        fp.write(render_template(file_path, input_data, out_path).encode('utf-8'))


def parse_args():
    import argparse
    parser = argparse.ArgumentParser(
        description="Render j2 templates",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter
    )
    parser.add_argument('input_files', help="Input files in the form of *.ext.j2", nargs='+')
    parser.add_argument('--data', help="JSON data to use as additional input. Can optionally be a path to a file.", default={})
    parser.add_argument('--extensions', help="jinja2 extensions to load", default=EXTENSIONS)
    parser.add_argument('--no-clobber', action='store_true', help="If set, don't overwrite files.", default=False)
    parser.add_argument('--pico8', action='store_true', help="Use alternate quote-based syntax", default=False)
    return parser.parse_args()


def main():
    global EXTENSIONS
    global NO_CLOBBER
    global PICO8_MODE
    args = parse_args()

    EXTENSIONS = args.extensions
    NO_CLOBBER = args.no_clobber
    PICO8_MODE = args.pico8
    input_data = {}
    if args.data:
        if os.path.isfile(args.data):
            with open(args.data, 'rb') as fp:
                input_data = json.loads(fp.decode('utf-8'))
        else:
            input_data = json.loads(args.data)

    for file in args.input_files:
        try:
            input_data.update({
                '_filepath': os.path.normpath(file),
                '_pathsplit': os.path.split(file),
                '_splitext': os.path.splitext(file)
            })
            auto_render_template(file, input_data)
        except IOError as e:
            print(e)
            continue


if __name__ == "__main__":
    main()