Source code for hermes_core.util.config

"""
This module provides configuration file functionality.

This code is based on that provided by SunPy see
    licenses/SUNPY.rst
"""

import os
import shutil
import configparser
from pathlib import Path

import hermes_core
from hermes_core.util.exceptions import warn_user

# This is to fix issue with AppDirs not writing to /tmp/ in AWS Lambda
if not os.getenv("LAMBDA_ENVIRONMENT"):
    from sunpy.extern.appdirs import AppDirs

__all__ = ["load_config", "copy_default_config", "print_config", "CONFIG_DIR"]

# Default directories for Lambda Environment
CONFIG_DIR = "/tmp/.config"
CACHE_DIR = "/tmp/.cache"

# This is to fix issue with AppDirs not writing to /tmp/ in AWS Lambda
if not os.getenv("LAMBDA_ENVIRONMENT"):
    # This is to avoid creating a new config dir for each new dev version.
    # We use AppDirs to locate and create the config directory.
    dirs = AppDirs("hermes_core", "hermes_core")
    # Default one set by AppDirs
    CONFIG_DIR = dirs.user_config_dir
    CACHE_DIR = dirs.user_cache_dir


def load_config():
    """
    Read the configuration file.

    If one does not exists in the user's home directory then read in the defaults.
    """
    config = configparser.RawConfigParser()

    # Get locations of configuration files to be loaded
    config_files = _find_config_files()

    # Read in configuration files
    config.read(config_files)

    # This is to fix issue with AppDirs not writing to /tmp/ in AWS Lambda
    if os.getenv("LAMBDA_ENVIRONMENT"):
        config.set("logger", "log_to_file", "False")

    # Specify the working directory as a default so that the user's home
    # directory can be located in an OS-independent manner
    if not config.has_option("general", "working_dir"):
        config.set("general", "working_dir", str(Path.home() / "hermes"))

    # Set the download_dir to be relative to the working_dir
    working_dir = Path(config.get("general", "working_dir"))
    download_dir = Path(config.get("downloads", "download_dir"))
    config.set(
        "downloads",
        "download_dir",
        (working_dir / download_dir).expanduser().resolve().as_posix(),
    )

    return config


def _find_config_files():
    """
    Finds locations of configuration files.
    """
    config_files = []
    config_filename = "configrc"

    # find default configuration file
    module_dir = Path(hermes_core.__file__).parent
    config_files.append(str(module_dir / "data" / "configrc"))

    # if a user configuration file exists, add that to list of files to read
    # so that any values set there will override ones specified in the default
    # config file
    config_path = Path(_get_user_configdir())
    if config_path.joinpath(config_filename).exists():
        config_files.append(str(config_path.joinpath(config_filename)))

    return config_files


def get_and_create_download_dir():
    """
    Get the config of download directory and create one if not present.
    """
    download_dir = os.environ.get("HERMES_DOWNLOADDIR")
    if download_dir:
        return download_dir

    download_dir = (
        Path(hermes_core.config.get("downloads", "download_dir")).expanduser().resolve()
    )
    if not _is_writable_dir(download_dir):
        raise RuntimeError(
            f'Could not write to hermes downloads directory="{download_dir}"'
        )

    return hermes_core.config.get("downloads", "download_dir")


def get_and_create_sample_dir():
    """
    Get the config of download directory and create one if not present.
    """
    sample_dir = (
        Path(hermes_core.config.get("downloads", "sample_dir")).expanduser().resolve()
    )
    if not _is_writable_dir(sample_dir):
        raise RuntimeError(
            f'Could not write to hermes sample data directory="{sample_dir}"'
        )

    return hermes_core.config.get("downloads", "sample_dir")




def print_config():
    """
    Print current configuration options.
    """
    print("FILES USED:")
    for file_ in _find_config_files():
        print("  " + file_)

    print("\nCONFIGURATION:")
    for section in hermes_core.config.sections():
        print(f"  [{section}]")
        for option in hermes_core.config.options(section):
            print(f"  {option} = {hermes_core.config.get(section, option)}")
        print("")



def _is_writable_dir(p):
    """
    Checks to see if a directory is writable.
    """
    # Worried about multiple threads creating the directory at the same time.
    try:
        Path(p).mkdir(parents=True, exist_ok=True)
    except FileExistsError:  # raised if there's an existing file instead of a directory
        return False
    else:
        return Path(p).is_dir() and os.access(p, os.W_OK)


def _get_user_configdir():
    """
    Return the string representing the configuration dir.

    The default is set by "AppDirs" and can be accessed by importing
    ``hermes.util.config.CONFIG_DIR``. You can override this with the
    "hermes_CONFIGDIR" environment variable.
    """
    configdir = os.environ.get("hermes_CONFIGDIR", CONFIG_DIR)

    if not _is_writable_dir(configdir):
        raise RuntimeError(f'Could not write to hermes_CONFIGDIR="{configdir}"')
    return configdir


def copy_default_config(overwrite=False):
    """
    Copies the default config file to the user's config directory.

    Parameters
    ----------
    overwrite : `bool`
        If True, existing config file will be overwritten.
    """
    config_filename = "configrc"
    config_file = Path(hermes_core.__file__).parent / "data" / config_filename
    user_config_dir = Path(_get_user_configdir())
    user_config_file = user_config_dir / config_filename

    if not _is_writable_dir(user_config_dir):
        raise RuntimeError(f"Could not write to config directory {user_config_dir}")

    if user_config_file.exists():
        if overwrite:
            message = (
                "User config file already exists. "
                "This will be overwritten with a backup written in the same location."
            )
            warn_user(message)
            os.rename(str(user_config_file), str(user_config_file) + ".bak")
            shutil.copyfile(config_file, user_config_file)
        else:
            message = (
                "User config file already exists. "
                "To overwrite it use `copy_default_config(overwrite=True)`"
            )
            warn_user(message)
    else:
        shutil.copyfile(config_file, user_config_file)