Loader¶

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

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

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]) – 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)¶

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

property is_default¶: Alias for field number 3

property parser_name¶: Alias for field number 4

property type¶: Alias for field number 2

property value¶: Alias for field number 1

property variable_path¶: Alias for field number 0