Configuration Service Core

The configuration service core provides a lightweight function to assist in the loading of environmental variables.

Methods

The configuration service core has only one public method, get_env

Args:

key_name - The name of the environment variable.

error_flag - If set to True and the env variable was not set, an error will be raised.

test_response - Value to return if in test mode.

default_value - A value to return if no other values are set. Error flag must be set to False or an error will be raised.

data_type_convert - Will convert the returned value to either a float, or int type. Allowed values are:

• None (default)
• int - Convert response to integer
• float - Converts response to float.
• bool
• list (assumes CSV). List can optionally have list_int to convert the list elements to int, or list_float to convert list elements to float.

legacy_key_name - Allows for an alternative env variable name to be set. For example, the main env variable might be set to DB_HOST_NAME. At some point in the past some systems used DBHOSTNAME. This second value can be included under legacy_key_name. A warning will be printed to the std output indicating that the user should update their .env file.

Examples

Usage as a parent class

In this method of implementation, the configuration service is inherited as a class. Env variables are setup a properties of the class.

from configservice import Config


class ConfigService(Config):

    def __init__(self, test_mode=False):
        super().__init__(test_mode)

    @property 
    def api_key(self):
        return self.get_env('API_KEY')

Direct usage

The package can be used directly to set a variable as well.

from configservice import Config

c = Config()
api_key = c.get_env('API_KEY')

Options

Simple get of an environmental variable

The most straight forward implementation simply requires the name of an environmental variable. If no error flags are set, and the environmental variable does not exist, the method will return None.

 api_key = get_env('API_KEY')

Raise an error if env is missing.

By default, if no env value is found for the requested key, the method will return None. If you would rather raise an error, the error_flag parameter can be set to true. If the env variable is not set a MissingEnviron error will be raised.

api_key = get_env('API_KEY', error_flag=True)

Set a default value

A default value can be set as a fallback if the requested env variable is not set.

db_port = get_env('DB_PORT', default_value=5432, data_type_convert='int')

Convert the return data type.

By default, all environmental variables will return as strings. By setting the data_type_convert parameter you can have the value return as an int, float, bool, or list. List has further options of list_int and list_float.

db_port = get_env('DB_PORT', data_type_convert='int')

Lists support CSV. For example if the env STORE_IDS was 5,2,1,4,5,3 and the option list_int is used, the system will return [5, 2, 1, 4, 5, 3]

store_ids = get_env('STORE_IDS', data_type_convert='list_int')

Test mode response.

Test mode can be set by either passing in test_mode when instantiating the class, or by setting the class parameter test_mode=True. Then the test_response parameter can be passed in to override any env variable. For example:

from configservice import Config

c = Config(test_mode=True)
api_key = c.get_env('API_KEY', test_response='ABC123')

This will return 'ABC123' regardless of if an env variable named API_KEY is set. This can be handy for unit testing.