docker-tidy/dockertidy/Config.py

#!/usr/bin/env python3
"""Global settings definition."""

import os

import anyconfig
import environs
import jsonschema.exceptions
import ruamel.yaml
from appdirs import AppDirs
from jsonschema._utils import format_as_index

import dockertidy.Exception
import dockertidy.Parser
from dockertidy.Parser import env
from dockertidy.Utils import Singleton

config_dir = AppDirs("docker-tidy").user_config_dir
default_config_file = os.path.join(config_dir, "config.yml")


class Config():
    """
    Create an object with all necessary settings.

    Settings are loade from multiple locations in defined order (last wins):
    - default settings defined by `self._get_defaults()`
    - yaml config file, defaults to OS specific user config dir
      see (https://pypi.org/project/appdirs/)
    - provides cli parameters
    """

    SETTINGS = {
        "config_file": {
            "default": "",
            "env": "CONFIG_FILE",
            "type": environs.Env().str
        },
        "dry_run": {
            "default": False,
            "env": "DRY_TUN",
            "file": True,
            "type": environs.Env().bool
        },
        "http_timeout": {
            "default": 60,
            "env": "HTTP_TIMEOUT",
            "file": True,
            "type": environs.Env().int
        },
        "logging.level": {
            "default": "WARNING",
            "env": "LOG_LEVEL",
            "file": True,
            "type": environs.Env().str
        },
        "logging.json": {
            "default": False,
            "env": "LOG_JSON",
            "file": True,
            "type": environs.Env().bool
        },
        "gc.max_container_age": {
            "default": "1day",
            "env": "GC_MAX_CONTAINER_AGE",
            "file": True,
            "type": env.timedelta_validator
        },
        "gc.max_image_age": {
            "default": "1day",
            "env": "GC_MAX_IMAGE_AGE",
            "file": True,
            "type": env.timedelta_validator
        },
        "gc.dangling_volumes": {
            "default": False,
            "env": "GC_EXCLUDE_IMAGE",
            "file": True,
            "type": environs.Env().bool
        },
        "gc.exclude_image": {
            "default": [],
            "env": "GC_DANGLING_VOLUMES",
            "file": True,
            "type": environs.Env().list
        },
        "gc.exclude_container_label": {
            "default": [],
            "env": "GC_EXCLUDE_CONTAINER_LABEL",
            "file": True,
            "type": environs.Env().list
        },
        "stop.max_run_time": {
            "default": "3days",
            "env": "STOP_MAX_RUN_TIME",
            "file": True,
            "type": env.timedelta_validator
        },
        "stop.prefix": {
            "default": [],
            "env": "STOP_PREFIX",
            "file": True,
            "type": environs.Env().list
        },
    }

    def __init__(self, args={}):
        """
        Initialize a new settings class.

        :param args: An optional dict of options, arguments and commands from the CLI.
        :param config_file: An optional path to a yaml config file.
        :returns: None

        """
        self._args = args
        self._schema = None
        self.config_file = default_config_file
        self.config = None
        self._set_config()

    def _get_args(self, args):
        cleaned = dict(filter(lambda item: item[1] is not None, args.items()))

        normalized = {}
        for key, value in cleaned.items():
            normalized = self._add_dict_branch(normalized, key.split("."), value)

        # Override correct log level from argparse
        levels = ["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"]
        log_level = levels.index(self.SETTINGS["logging.level"]["default"])
        if normalized.get("logging"):
            for adjustment in normalized["logging"]["level"]:
                log_level = min(len(levels) - 1, max(log_level + adjustment, 0))
            normalized["logging"]["level"] = levels[log_level]

        return normalized

    def _get_defaults(self):
        normalized = {}
        for key, item in self.SETTINGS.items():
            normalized = self._add_dict_branch(normalized, key.split("."), item["default"])

        self.schema = anyconfig.gen_schema(normalized)
        return normalized

    def _get_envs(self):
        normalized = {}
        for key, item in self.SETTINGS.items():
            if item.get("env"):
                prefix = "TIDY_"
                envname = prefix + item["env"]
                try:
                    value = item["type"](envname)
                    normalized = self._add_dict_branch(normalized, key.split("."), value)
                except environs.EnvError as e:
                    if '"{}" not set'.format(envname) in str(e):
                        pass
                    else:
                        raise dockertidy.Exception.ConfigError(
                            "Unable to read environment variable", str(e)
                        )

        return normalized

    def _set_config(self):
        args = self._get_args(self._args)
        envs = self._get_envs()
        defaults = self._get_defaults()

        # preset config file path
        if envs.get("config_file"):
            self.config_file = self._normalize_path(envs.get("config_file"))

        if args.get("config_file"):
            self.config_file = self._normalize_path(args.get("config_file"))

        source_files = []
        source_files.append(self.config_file)
        source_files.append(os.path.join(os.getcwd(), ".dockertidy"))
        source_files.append(os.path.join(os.getcwd(), ".dockertidy.yml"))
        source_files.append(os.path.join(os.getcwd(), ".dockertidy.yaml"))

        for config in source_files:
            if config and os.path.exists(config):
                with open(config, "r", encoding="utf8") as stream:
                    s = stream.read()
                    try:
                        file_dict = ruamel.yaml.safe_load(s)
                    except (
                        ruamel.yaml.composer.ComposerError, ruamel.yaml.scanner.ScannerError
                    ) as e:
                        message = "{} {}".format(e.context, e.problem)
                        raise dockertidy.Exception.ConfigError(
                            "Unable to read config file {}".format(config), message
                        )

                    if self._validate(file_dict):
                        anyconfig.merge(defaults, file_dict, ac_merge=anyconfig.MS_DICTS)
                        defaults["logging"]["level"] = defaults["logging"]["level"].upper()

        if self._validate(envs):
            anyconfig.merge(defaults, envs, ac_merge=anyconfig.MS_DICTS)

        if self._validate(args):
            anyconfig.merge(defaults, args, ac_merge=anyconfig.MS_DICTS)

        if "config_file" in defaults:
            defaults.pop("config_file")

        defaults["logging"]["level"] = defaults["logging"]["level"].upper()

        self.config = defaults

    def _normalize_path(self, path):
        if not os.path.isabs(path):
            base = os.path.join(os.getcwd(), path)
            return os.path.abspath(os.path.expanduser(os.path.expandvars(base)))
        else:
            return path

    def _validate(self, config):
        try:
            anyconfig.validate(config, self.schema, ac_schema_safe=False)
        except jsonschema.exceptions.ValidationError as e:
            schema_error = "Failed validating '{validator}' in schema{schema}\n{message}".format(
                validator=e.validator,
                schema=format_as_index(list(e.relative_schema_path)[:-1]),
                message=e.message
            )
            raise dockertidy.Exception.ConfigError("Configuration error", schema_error)

        return True

    def _add_dict_branch(self, tree, vector, value):
        key = vector[0]
        tree[key] = value \
            if len(vector) == 1 \
            else self._add_dict_branch(tree[key] if key in tree else {}, vector[1:], value)
        return tree


class SingleConfig(Config, metaclass=Singleton):
    pass