[python] add method to set/get default configuration (#5315)

* [python] add method to set/get default configuration

* [python] change method name and fix handling api_key

* python: using modified deepcopy to set/get default configuration

* python: update samples

* python: update samples

samples/client/petstore/python/petstore_api/api_client.py

@@ -68,7 +68,7 @@ class ApiClient(object):
     def __init__(self, configuration=None, header_name=None, header_value=None,
                  cookie=None, pool_threads=1):
         if configuration is None:
-            configuration = Configuration()
+            configuration = Configuration.get_default_copy()
         self.configuration = configuration
         self.pool_threads = pool_threads
 

samples/client/petstore/python/petstore_api/configuration.py

@@ -12,6 +12,7 @@
 
 from __future__ import absolute_import
 
+import copy
 import logging
 import multiprocessing
 import sys
@@ -83,6 +84,8 @@ class Configuration(object):
       )
     """
 
+    _default = None
+
     def __init__(self, host="http://petstore.swagger.io:80/v2",
                  api_key=None, api_key_prefix=None,
                  username=None, password=None,
@@ -182,6 +185,45 @@ class Configuration(object):
         # Disable client side validation
         self.client_side_validation = True
 
+    def __deepcopy__(self, memo):
+        cls = self.__class__
+        result = cls.__new__(cls)
+        memo[id(self)] = result
+        for k, v in self.__dict__.items():
+            if k not in ('logger', 'logger_file_handler'):
+                setattr(result, k, copy.deepcopy(v, memo))
+        # shallow copy of loggers
+        result.logger = copy.copy(self.logger)
+        # use setters to configure loggers
+        result.logger_file = self.logger_file
+        result.debug = self.debug
+        return result
+
+    @classmethod
+    def set_default(cls, default):
+        """Set default instance of configuration.
+
+        It stores default configuration, which can be
+        returned by get_default_copy method.
+
+        :param default: object of Configuration
+        """
+        cls._default = copy.deepcopy(default)
+
+    @classmethod
+    def get_default_copy(cls):
+        """Return new instance of configuration.
+
+        This method returns newly created, based on default constructor,
+        object of Configuration class or returns a copy of default
+        configuration passed by the set_default method.
+
+        :return: The configuration object.
+        """
+        if cls._default is not None:
+            return copy.deepcopy(cls._default)
+        return Configuration()
+
     @property
     def logger_file(self):
         """The logger file.