AsSq74QC

1import os
2from librarian.utils.enums import StreamFormat, VideoFileCodec
3
4
5def string_to_bool(str_):
6    return str_ and str_.lower() not in ['false', '0']
7
8
9class ConfigError(Exception):
10    pass
11
12
13class ConfigField:
14    def __init__(self, processor=str, default=None, required=False):
15        self.processor = processor
16        self.default = default
17        self.required = required
18
19
20class EnvironConfigurationMeta(type):
21    def __call__(cls, *args, **kwargs):
22        raise Exception("Can't instance a configuration class")
23
24    def __init__(cls, name, bases, dct):
25        super(EnvironConfigurationMeta, cls).__init__(name, bases, dct)
26        if cls._load_all_from_environ:
27            for var, value in os.environ.items():
28                if not var.upper() in [k.upper() for k in dct.keys()]:
29                    dct[var.upper()] = ConfigField(processor=str, default=None,
30                                             required=False)
31
32        for k, field in dct.items():
33            if isinstance(field, ConfigField):
34                config_val = os.environ.get(k)
35                if config_val:
36                    config_val = field.processor(config_val)
37                elif field.default:
38                    if callable(field.default):
39                        config_val = field.default()
40                    else:
41                        config_val = field.default
42                if config_val is None and field.required:
43                    raise ConfigError(f'Config param {k} can not be None')
44
45                setattr(cls, k, config_val)
46
47    def __getitem__(cls, item):
48        return getattr(cls, item)
49
50
51class BaseEnvironConfig(metaclass=EnvironConfigurationMeta):
52    """Base config class.
53    Loads all config params that are instances of ConfigField from environ,
54    applies preprocessor, validates if required.
55
56    `_load_all_from_environ` - if true will load all env vars as non-required
57    fields.
58
59    Example:
60    ```
61    >>> class Config(BaseEnvironConfig):
62    ...  DEBUG = ConfigField(processor=string_to_bool, default=True)
63    ...
64    >>> Config.DEBUG
65    True
66    ```
67
68    Loads env var "DEBUG", applies function `string_to_bool` to the returned value,
69    if the result is None uses default of True.
70
71    Since its a global class it's __VERY IMPORTANT__ to import it like this:
72
73    ```
74    from package import module
75    print(module.ConfigClass.as_text())
76    ```
77
78    and __not__ like this:
79
80    ```
81    from package.module import ConfigClass
82    print(ConfigClass.as_text())
83    ```
84
85    The first variant allows you to monkey patch the config during testing.
86    Pytest example:
87
88    ```
89    from package.module import ConfigClass
90
91    class TestConfig(ConfigClass):
92        pass
93
94    TestConfig.TEST = True
95
96    monkeypatch.setattr('package.module.ConfigClass', TestConfig)
97    ```
98
99    After this all code accesing `module.ConfigClass` will get `TestConfig`.
100    """
101
102    _load_all_from_environ = False
103
104    @classmethod
105    def as_dict(cls):
106        non_private_attrs = [(k, v) for k, v in vars(cls).items() if
107                             not k.startswith('_')]
108        data_fields = {k: v for k, v in non_private_attrs if
109                       not callable(getattr(cls, k))}
110        return data_fields
111
112    @classmethod
113    def as_text(cls, exclude=[]):
114        exclude = [x.lower() for x in exclude]
115        data_fields = cls.as_dict()
116        attrs = [
117            "{}={}".format(k, str(v) if not k.lower() in exclude else '*' * len(v))
118            for k, v in data_fields.items() if v]
119        attrs.sort()  # sorts normally by alphabetical order
120        attrs.sort(key=len, reverse=False)  # sorts by descending length
121        return "Config:\n\t" + '\n\t'.join(attrs)
122
123
124class AkamaiConfig(BaseEnvironConfig):
125    AKAMAI_LINK_PROTECT_WINDOW = ConfigField(required=True)
126    AKAMAI_LINK_PROTECT_SALT = ConfigField(required=True)
127    AKAMAI_LINK_PROTECT_ALGO = ConfigField(required=True)
128    AKAMAI_LINK_PROTECT_KEY = ConfigField(required=True)
129    AKAMAI_LINK_PROTECT_FIELD_DELIMITER = ConfigField(required=True)
130
131
132class Configuration(BaseEnvironConfig):
133
134    _load_all_from_environ = False
135
136    # Flask configs
137    DEBUG = ConfigField(processor=string_to_bool, default=True)
138    TESTING = ConfigField(processor=string_to_bool, default=False)
139    DB_ECHO = ConfigField(processor=string_to_bool, default=False)
140    SECRET_KEY = ConfigField(default=__name__)
141    SQLALCHEMY_URL = ConfigField(required=True)
142
143    # Custom configs
144    GEO_ROUTING_FILE = ConfigField(required=True)
145    STREAM_FORMATS = ConfigField(processor=lambda var: [StreamFormat.from_string(fmt) for fmt in var.split(',')], required=True)
146    CODECS = ConfigField(processor=lambda var: [VideoFileCodec.from_string(codec) for codec in var.split(',')], required=True)
147    PREFERRED_REDIRECT_SCHEME = ConfigField(required=True, default='https')