Create/Read a default config.toml file

create_default_toml.py

## Brian Blaylock
## August 7, 2021

# borrowed from Herbie package.
# use in __init__.py to create/read config.toml for package.

import toml
import os
from pathlib import Path

########################################################################
# Append Path object with my custom expand method so user can use
# environment variables in the config file (e.g., ${HOME}).
def _expand(self):
    """
    Fully expand and resolve the Path with the given environment variables.

    Example
    -------
    >>> Path('$HOME').expand()
    >>> PosixPath('/p/home/blaylock')
    """
    return Path(os.path.expandvars(self)).expanduser().resolve()


Path.expand = _expand

########################################################################
# Herbie configuration file
# Configuration file is save in `~/config/herbie/config.toml`
_config_path = Path("~/.config/herbie/config.toml").expand()

# NOTE: The `\\` is an escape character in TOML. 
# For Windows paths "C:\\user\\"" needs to be "C:\\\\user\\\\""
_save_dir = str(Path('~/data').expand())
_save_dir = _save_dir.replace('\\', '\\\\')


########################################################################
# Default TOML Configuration Values
default_toml = f"""
['default']
model = "hrrr"
fxx = 0
priority = ['aws', 'nomads', 'google', 'azure', 'pando', 'pando2', 'aws-old']
save_dir = "{_save_dir}"
overwrite = false
verbose = true
"""

########################################################################
# If a config file isn't found, make one with default settings above
if not _config_path.exists():
    with open(_config_path, "w") as f:
        toml_string = toml.dump(toml.loads(default_toml), f)
    print(f"⚙ Created config file [{_config_path}] with default values.")

########################################################################
# Read the config file
config = toml.load(_config_path)

config["default"]["save_dir"] = Path(config["default"]["save_dir"]).expand()