Loader¶

class django_docker_helpers.config.ConfigLoader(parsers, silent=False, suppress_logs=False, keep_read_records_max=1024)[source]¶

Bases: object

provides a single interface to read from specified config parsers in order they present;
tracks accessed from parsers options;
prints config options access log in pretty-print way.

Example

env = {
    'PROJECT__DEBUG': 'false'
}
parsers = [
    EnvironmentParser(scope='project', env=env),
    RedisParser('my/conf/service/config.yml', host=REDIS_HOST, port=REDIS_PORT),
    YamlParser(config='./tests/data/config.yml', scope='project'),
]
configure = ConfigLoader(parsers=parsers)

DEBUG = configure('debug')  # 'false'
DEBUG = configure('debug', coerce_type=bool)  # False

Initialization:

takes a list of initialized parsers;
it’s supposed to use ONLY unique parsers for parsers argument (or you are going to get the same initial arguments for all parsers of the same type in from_env());
the parsers’s order does matter.

Parameters:	parsers (`List`[`BaseParser`]) – a list of initialized parsers silent (`bool`) – don’t raise exceptions if any read attempt failed suppress_logs (`bool`) – don’t display any exception warnings on screen keep_read_records_max (`int`) – max capacity queue length

__call__(variable_path, default=None, coerce_type=None, coercer=None, required=False, **kwargs)[source]¶: A useful shortcut for method get()

format_config_read_queue(use_color=False, max_col_width=50)[source]¶

Prepares a string with pretty printed config read queue.

Parameters:	use_color (`bool`) – use terminal colors max_col_width (`int`) – limit column width, `50` by default
Return type:	`str`
Returns:

static from_env(parser_modules=('django_docker_helpers.config.backends.EnvironmentParser', 'django_docker_helpers.config.backends.MPTRedisParser', 'django_docker_helpers.config.backends.MPTConsulParser', 'django_docker_helpers.config.backends.RedisParser', 'django_docker_helpers.config.backends.ConsulParser', 'django_docker_helpers.config.backends.YamlParser'), env=None, silent=False, suppress_logs=False, extra=None)[source]¶

Creates an instance of ConfigLoader with parsers initialized from environment variables.

By default it tries to initialize all bundled parsers. Parsers may be customized with parser_modules argument or CONFIG__PARSERS environment variable. Environment variable has a priority over the method argument.

Parameters:	parser_modules (`Union`[`List`[`str`], `Tuple`[`str`], `None`]) – a list of dot-separated module paths env (`Optional`[`Dict`[`str`, `str`]]) – a dict with environment variables, default is `os.environ` silent (`bool`) – passed to `ConfigLoader` suppress_logs (`bool`) – passed to `ConfigLoader` extra (`Optional`[`dict`]) – pass extra arguments to every parser
Return type:	`ConfigLoader`
Returns:	an instance of `ConfigLoader`

Example:

env = {
    'CONFIG__PARSERS': 'EnvironmentParser,RedisParser,YamlParser',
    'ENVIRONMENTPARSER__SCOPE': 'nested',
    'YAMLPARSER__CONFIG': './tests/data/config.yml',
    'REDISPARSER__HOST': 'wtf.test',
    'NESTED__VARIABLE': 'i_am_here',
}

loader = ConfigLoader.from_env(env=env)
assert [type(p) for p in loader.parsers] == [EnvironmentParser, RedisParser, YamlParser]
assert loader.get('variable') == 'i_am_here', 'Ensure env copied from ConfigLoader'

loader = ConfigLoader.from_env(parser_modules=['EnvironmentParser'], env={})

get(variable_path, default=None, coerce_type=None, coercer=None, required=False, **kwargs)[source]¶

Tries to read a variable_path from each of the passed parsers. It stops if read was successful and returns a retrieved value. If none of the parsers contain a value for the specified path it returns default.

Parameters:	variable_path (`str`) – a path to variable in config default (`Optional`[`Any`]) – a default value if `variable_path` is not present anywhere coerce_type (`Optional`[`Type`[+CT_co]]) – cast a result to a specified type coercer (`Optional`[`Callable`]) – perform the type casting with specified callback required (`bool`) – raise `RequiredValueIsEmpty` if no `default` and no result kwargs – additional options to all parsers
Returns:	the first successfully read value from the list of parser instances or `default`
Raises:	config.exceptions.RequiredValueIsEmpty – if nothing is read,``required`` flag is set, and there’s no `default` specified

static import_parsers(parser_modules)[source]¶

Resolves and imports all modules specified in parser_modules. Short names from the local scope are supported (the scope is django_docker_helpers.config.backends).

Parameters:	parser_modules (`Iterable`[`str`]) – a list of dot-separated module paths
Return type:	`Generator`[`Type`[`BaseParser`], `None`, `None`]
Returns:	a generator of [probably] `BaseParser`

Example:

parsers = list(ConfigLoader.import_parsers([
    'EnvironmentParser',
    'django_docker_helpers.config.backends.YamlParser'
]))
assert parsers == [EnvironmentParser, YamlParser]

static load_parser_options_from_env(parser_class, env=None)[source]¶

Extracts arguments from parser_class.__init__ and populates them from environment variables.

Uses __init__ argument type annotations for correct type casting.

Note

Environment variables should be prefixed with <UPPERCASEPARSERCLASSNAME>__.

Parameters:	parser_class (`Type`[`BaseParser`]) – a subclass of `BaseParser` env (`Optional`[`Dict`[`str`, `str`]]) – a dict with environment variables, default is `os.environ`
Return type:	`Dict`[`str`, `Any`]
Returns:	parser’s `__init__` arguments dict mapping

Example:

env = {
    'REDISPARSER__ENDPOINT': 'go.deep',
    'REDISPARSER__HOST': 'my-host',
    'REDISPARSER__PORT': '66',
}

res = ConfigLoader.load_parser_options_from_env(RedisParser, env)
assert res == {'endpoint': 'go.deep', 'host': 'my-host', 'port': 66}

print_config_read_queue(use_color=False, max_col_width=50)[source]¶

Prints all read (in call order) options.

Parameters:	max_col_width (`int`) – limit column width, `50` by default use_color (`bool`) – use terminal colors
Returns:	nothing

class django_docker_helpers.config.ConfigReadItem(variable_path, value, type, is_default, parser_name)¶

Bases: tuple

Create new instance of ConfigReadItem(variable_path, value, type, is_default, parser_name)

__getnewargs__()¶: Return self as a plain tuple. Used by copy and pickle.

static __new__(_cls, variable_path, value, type, is_default, parser_name)¶: Create new instance of ConfigReadItem(variable_path, value, type, is_default, parser_name)

__repr__()¶: Return a nicely formatted representation string

_asdict()¶: Return a new OrderedDict which maps field names to their values.

classmethod _make(iterable, new=<built-in method __new__ of type object>, len=<built-in function len>)¶: Make a new ConfigReadItem object from a sequence or iterable

_replace(**kwds)¶: Return a new ConfigReadItem object replacing specified fields with new values

is_default¶: Alias for field number 3

parser_name¶: Alias for field number 4

type¶: Alias for field number 2

value¶: Alias for field number 1

variable_path¶: Alias for field number 0