gean 0.0.3

A minimal IOC container inspired by Spring

gean

A minimal IOC container inspired by Spring.

Install

python3 -m pip install gean

Example

from gean import Container, includes

class Michael:
  def speak(self):
    return 'what'

@includes(Michael)
class WhateverModule:
  def whatever(self) -> int:
    return 42

  def world(self) -> int:
    return 100

class Application:
  my_dir: str
  whatever: 'int'
  world: int
  m: Michael

  def start(self):
    print(self.my_dir)
    print(self.whatever)
    print(self.world)
    print(self.m.speak())

@includes(
  WhateverModule,
  Application,
  Michael,
)
class ApplicationModule:
  config_dir: str

  def another_dir(self) -> str:
    return self.config_dir + '/another'

  def my_dir(self, another_dir: 'str') -> str:
    return another_dir + '/ñe'

def _main():
  container = Container()
  container.register_instance('/etc/hello/world', name='config_dir')
  container.register_module(ApplicationModule)
  container.resolve(Application).start()

if __name__ == '__main__':
  _main()

Requirements

gean, like Spring, relies on types and signatures to build and resolve the dependency graph.

Required language features:

• PEP 484 - Type Hints (Python 3.5+)
• PEP 526 - Syntax for Variable Annotations (Python 3.6+)

Design

Dependency registration

Each dependency of type T is registered not only as T but also as all of its implemented interfaces throguh its inheritance hierarchy.

Dependencies may be explicitly named if multiple of the same type are needed.

Dependency kinds

Instances: the provided type is type(instance)

Classes: the provided type is cls itself

Callables: the provided type is get_type_hints(callable)['return']

Modules: for each public method of the module m, the provided type is get_type_hints(m)['return']. Additionally, each dependency is automatically named after the module method that provides it.

History

gean started off as a gist I created to show @alexpizarroj how my team leverages Spring in our projects.