The gemstone.config module

Configurables

class gemstone.config.Configurable(name, *, template=None)

Defines a configurable value for the application.

Example (You should not use configurables in this way unless you are writing a custom Configurator)

c = Configurable("test", template=lambda x: x * 2)
c.set_value("10")
c.get_final_value()  # "10" * 2 -> 1010

c2 = Configurable("list_of_ints", template=lambda x: [int(y) for y in x.split(",")])
c.set_value("1,2,3,4,5")
c.get_final_value()  # [1,2,3,4,5]

Parameters:

• name – The name of the configurable parameter
• template – A callable template to apply over the extracted value

Configurators

class gemstone.config.BaseConfigurator

Base class for defining configurators. A configurator is a class that, starting from a set of name-configurable pairs, depending on the configurables’ options and the environment, builds a configuration for the application.

get(name)

Gets the extracted value for the specified name, if available. If no value could be loaded for the specified name, None must be returned.

get_configurable_by_name(name)

Returns the registered configurable with the specified name or None if no such configurator exists.

load()

Loads the configuration for the application

register_configurable(configurable)

Registers a configurable instance with this configurator

Parameters:configurable – a Configurable instance

class gemstone.config.CommandLineConfigurator

Configurator that collects values from command line arguments. For each registered configurable, will attempt to get from command line the value designated by the argument --name where name is the name of the configurable.

Example

For the configurables

• Configurable(“a”)
• Configurable(“b”)
• Configurable(“c”)

the following command line interface will be exposed

usage: service.py [-h] [--a A] [--b B] [--c C]

optional arguments:
  -h, --help  show this help message and exit
  --a A
  --b B
  --c C

The service.py can be called like this

python service.py --a=1 --b=2 --c=3