Add container.py

container.py

@@ -0,0 +1,68 @@
+from dataclasses import dataclass
+from types import LambdaType, FunctionType
+from typing import Mapping, Type, TypeVar
+
+T = TypeVar("T")
+
+class ServiceLookupException(Exception):
+    pass 
+
+@dataclass
+class ServiceContainer:
+    _singletons: Mapping[str, T]
+    _factories: Mapping[str, T]
+    
+    def register_name(self, name: str, instance: T) -> None:
+        if type(instance) is LambdaType or type(instance) is FunctionType:
+            self._factories[name] = instance
+        else:
+            self._singletons[name] = instance
+            
+    def retrieve_name(self, name: str, _: Type[T]) -> T:
+        if name in self._singletons:
+            return self._singletons[name]
+        elif name in self._factories:
+            return self._factories[name]()
+        
+        raise ServiceLookupException(f"Could not locate service with name {name}")
+    
+    def register_type(self, instance: T) -> None:
+        t = type(instance)
+        name = str(Type[t])
+        if type(instance) is LambdaType or type(instance) is FunctionType:
+            self._factories[name] = instance
+        else:
+            self._singletons[name] = instance
+            
+    def retrieve_type(self, desired_type: Type[T]) -> T:
+        name = str(desired_type)
+        if name in self._singletons:
+            return self._singletons[name]
+        elif name in self._factories:
+            return self._factories[name]()
+        
+        raise ServiceLookupException(f"Could not locate service with name {name}")    
+        
+        
+@dataclass
+class Foo:
+    bar: str
+    
+    def __post_init__(self):
+        print(f"Initialized with {self.bar}")
+    
+    
+container = ServiceContainer({}, {})
+container.register_name("foo_lam", lambda : Foo("bar"))
+foo_single = Foo("baz")
+container.register_name("foo_single", foo_single)
+
+mc1 = container.retrieve_name("foo_lam", Type[Foo])
+mc2 = container.retrieve_name("foo_lam", Type[Foo])
+mc3 = container.retrieve_name("foo_single", Type[Foo])
+mc4 = container.retrieve_name("foo_single", Type[Foo])
+
+print(mc1.bar)
+print(mc2.bar)
+print(mc3.bar)
+print(mc4.bar)