wmb.py

import argparse
import os
import pathlib
import json


DEFAULT_CONFIG_DIR = "/opt/wurstmineberg/config/"

CONFIG_DIR = pathlib.Path(os.getenv("WURSTMINEBERG_CONFIG_DIR",
                                    default = DEFAULT_CONFIG_DIR))


_COPY_PROMPT = """The file

{file}

does not exist, create it? [yN]"""


def is_dev():
    """
Are we using a dev instance?
    """
    #prefer to read env over importing uwsgi
    if "WURSTMINEBERG_IS_DEV" in os.environ:
        return True
    try:
        import uwsgi
        return uwsgi.opt['is_dev'] == 'true' or uwsgi.opt['is_dev'] == b'true'
    except:
        return False


def _from_file(configfile):
    with configfile:
        return json.load(configfile)


def _get_base_config(name, base):
    if base is None:
        return {}

    # from_assets uses "{name}" as a placeholder
    base = base.with_name(base.name.format(name = name))
    return _from_file(base.open("r"))


def _get_passed_configfile():
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument("--config", type = argparse.FileType("r"))
    (args, _) = parser.parse_known_args()
    return args.config


def _prompt_copy_config(name, e):
    import sys
    if not sys.__stdin__.isatty():
        return False
    response = input(_COPY_PROMPT.format(file = e.filename))
    if response.lower() == "y":
        with _get_configfile(name, mode = "w") as configfile:
            json.dump({}, configfile)
        return True
    return False


def _get_configfile(name, mode = "r"):
    try:
        return (CONFIG_DIR / "{}.json".format(name)).open(mode)
    except FileNotFoundError as e:
        #print(e)
        if _prompt_copy_config(name, e):
            return _get_configfile(name)
        else:
            return None


def _apply_value_types(config, value_types):
    # value_types is a dict of key: type pairs.
    # If a type for a key is defined, convert to that type (otherwise apply the
    # identity function (ie do nothing)).
    # Mainly useful for things like paths that don't have a JSON representation
    return { key: value_types.get(key, lambda x: x)(value) for key, value in config.items() }


def _json_recursive_merge(json_values):
    json_values = iter(json_values)
    try:
        first = next(json_values)
    except StopIteration:
        return None
    if isinstance(first, dict):
        objects_prefix = [first]
        for value in json_values:
            if isinstance(value, dict):
                objects_prefix.append(value)
            else:
                break
        return {k: _json_recursive_merge(value[k] for value in objects_prefix if isinstance(value, dict) and k in value) for k in set.union(*(set(d.keys()) for d in objects_prefix))}
    else:
        return first


def get_config(name, base = None, argparse_configfile = True, value_types = None):
    if is_dev():
        name = "{}.dev".format(name)

    config = _get_base_config(name, base)

    passed_configfile = None
    if argparse_configfile:
        passed_configfile = _get_passed_configfile()

    if passed_configfile is None:
        configfile = _get_configfile(name)
    else:
        configfile = passed_configfile

    if not configfile is None:
        config = _json_recursive_merge((_from_file(configfile), config))

    if not value_types is None:
        config = _apply_value_types(config, value_types)

    return config


def from_assets(script_file):
    script_dir = pathlib.Path(script_file).resolve().parent
    return script_dir / "assets" / "{name}.default.json"


if __name__ == "__main__":
    print(get_config("example"))
    print(get_config("example", base = from_assets(__file__), argparse_configfile = False))