matrix-alertbot/matrix_alertbot/config.py

import logging
import os
import re
import sys
from typing import Any, List, Optional

import pytimeparse
import yaml

from matrix_alertbot.errors import (
    InvalidConfigError,
    ParseConfigError,
    RequiredConfigKeyError,
)

logger = logging.getLogger()
logging.getLogger("peewee").setLevel(
    logging.INFO
)  # Prevent debug messages from peewee lib


class Config:
    """Creates a Config object from a YAML-encoded config file from a given filepath"""

    def __init__(self, filepath: str):
        self.filepath = filepath
        if not os.path.isfile(filepath):
            raise ParseConfigError(f"Config file '{filepath}' does not exist")

        # Load in the config file at the given filepath
        with open(filepath) as file_stream:
            self.config_dict = yaml.safe_load(file_stream.read())

        # Parse and validate config options
        self._parse_config_values()

    def _parse_config_values(self) -> None:
        """Read and validate each config option"""
        # Logging setup
        formatter = logging.Formatter(
            "%(asctime)s | %(name)s [%(levelname)s] %(message)s"
        )

        log_level = self._get_cfg(["logging", "level"], default="INFO")
        logger.setLevel(log_level)

        file_logging_enabled = self._get_cfg(
            ["logging", "file_logging", "enabled"], default=False
        )
        file_logging_filepath = self._get_cfg(
            ["logging", "file_logging", "filepath"], default="matrix-alertbot.log"
        )
        if file_logging_enabled:
            file_handler = logging.FileHandler(file_logging_filepath)
            file_handler.setFormatter(formatter)
            logger.addHandler(file_handler)

        console_logging_enabled = self._get_cfg(
            ["logging", "console_logging", "enabled"], default=True
        )
        if console_logging_enabled:
            console_handler = logging.StreamHandler(sys.stdout)
            console_handler.setFormatter(formatter)
            logger.addHandler(console_handler)

        # Storage setup
        self.store_dir: str = self._get_cfg(["storage", "path"], required=True)

        # Create the store folder if it doesn't exist
        if not os.path.isdir(self.store_dir):
            if not os.path.exists(self.store_dir):
                os.mkdir(self.store_dir)
            else:
                raise InvalidConfigError(
                    f"storage.path '{self.store_dir}' is not a directory"
                )

        # Cache setup
        self.cache_dir: str = self._get_cfg(["cache", "path"], required=True)
        expire_time: str = self._get_cfg(["cache", "expire_time"], default="1w")
        self.cache_expire_time = pytimeparse.parse(expire_time)

        # Alertmanager client setup
        self.alertmanager_url: str = self._get_cfg(
            ["alertmanager", "url"], required=True
        )

        # Matrix bot account setup
        self.user_id: str = self._get_cfg(["matrix", "user_id"], required=True)
        if not re.match("@.+:.+", self.user_id):
            raise InvalidConfigError("matrix.user_id must be in the form @name:domain")

        self.user_password: str = self._get_cfg(
            ["matrix", "user_password"], required=False
        )
        self.user_token: str = self._get_cfg(["matrix", "user_token"], required=False)
        if not self.user_token and not self.user_password:
            raise RequiredConfigKeyError("Must supply either user token or password")

        self.device_id: str = self._get_cfg(["matrix", "device_id"], required=True)
        self.device_name: str = self._get_cfg(
            ["matrix", "device_name"], default="matrix-alertbot"
        )
        self.homeserver_url: str = self._get_cfg(["matrix", "url"], required=True)
        self.allowed_rooms: list = self._get_cfg(
            ["matrix", "allowed_rooms"], required=True
        )

        self.address: str = self._get_cfg(["webhook", "address"], required=False)
        self.port: int = self._get_cfg(["webhook", "port"], required=False)
        self.socket: str = self._get_cfg(["webhook", "socket"], required=False)
        if (
            not (self.address or self.port or self.socket)
            or (self.address and not self.port)
            or (not self.address and self.port)
        ):
            raise RequiredConfigKeyError(
                "Must supply either webhook.socket or both webhook.address and webhook.port"
            )
        elif self.socket and self.address and self.port:
            raise InvalidConfigError(
                "Supplied both webhook.socket and both webhook.address"
            )

        self.command_prefix: str = (
            self._get_cfg(["command_prefix"], default="!alert") + " "
        )

    def _get_cfg(
        self,
        path: List[str],
        default: Optional[Any] = None,
        required: bool = True,
    ) -> Any:
        """Get a config option from a path and option name, specifying whether it is
        required.

        Raises:
            RequiredConfigKeyError: If required is True and the object is not found (and there is
                no default value provided), a ConfigError will be raised.
        """
        # Sift through the the config until we reach our option
        config = self.config_dict
        for name in path:
            config = config.get(name)

            # If at any point we don't get our expected option...
            if config is None:
                # Raise an error if it was required
                if required and default is None:
                    raise RequiredConfigKeyError(
                        f"Config option {'.'.join(path)} is required"
                    )

                # or return the default value
                return default

        # We found the option. Return it.
        return config