Remove singleton class in FakeServerManager class

The current fake NFVO server design is based on a singleton class
pattern which restricts the instantiation of a class to one server
object.
Multi-tenant functional test case environment requires multiple
fake NFVO servers(one server per tenant).

This patch removes the SingletonMixin class and modifies the
FakeServerManager class to instantiate multiple server class objects.

Implement: blueprint multi-tenant-policy
Change-Id: Ia83aad3a8255ea6ee8cddc01e6a75c7e0e7945b8

tacker/tests/functional/common/fake_server.py

@@ -26,74 +26,8 @@ from oslo_log import log as logging
 LOG = logging.getLogger(__name__)
 
 
-class SingletonMixin:
+def PrepareRequestHandler(manager):
-    """Mixin class to make your class a Singleton class."""
+    class DummyRequestHandler(http.server.CGIHTTPRequestHandler):
-
-    _instance = None
-    _rlock = threading.RLock()
-    _inside_instance = False
-
-    @classmethod
-    def get_instance(cls, *args, **kwargs):
-        """Get *the* instance of the class, constructed when needed using(kw)args.
-
-        Return the instance of the class. If it did not yet exist, create
-        it by calling the "constructor" with whatever arguments and keyword
-        arguments provided.
-
-        This routine is thread-safe. It uses the *double-checked locking*
-        design pattern ``https://en.wikipedia.org/wiki/Double-checked_locking``
-        for this.
-
-        :param args: Used for constructing the instance, when not performed
-        yet.
-        :param kwargs: Used for constructing the instance, when not
-        perfored yet.
-        :return: An instance of the class.
-        """
-        if cls._instance is not None:
-            return cls._instance
-        with cls._rlock:
-            # re-check, perhaps it was created in the mean time...
-            if cls._instance is None:
-                cls._inside_instance = True
-                try:
-                    cls._instance = cls(*args, **kwargs)
-                finally:
-                    cls._inside_instance = False
-        return cls._instance
-
-    def __new__(cls, *args, **kwargs):
-        """Raise Exception when not called from the :func:``instance``
-
-        Class method.
-        This method raises RuntimeError when not called from the
-        instance class method.
-
-        :param args: Arguments eventually passed to
-        :func:``__init__``_.
-        :param kwargs: Keyword arguments eventually passed to
-        :func:``__init__``_
-        :return: the created instance.
-        """
-        if cls is SingletonMixin:
-            raise TypeError(
-                "Attempt to instantiate\
-                    mixin class {}".format(cls.__qualname__)
-            )
-
-        if cls._instance is None:
-            with cls._rlock:
-                if cls._instance is None and cls._inside_instance:
-                    return super().__new__(cls, *args, **kwargs)
-
-        raise RuntimeError(
-            "Attempt to create a {}\
-                instance outside of instance()".format(cls.__qualname__)
-        )
-
-
-class DummyRequestHander(http.server.CGIHTTPRequestHandler):
         """HTTP request handler for dummy server."""
 
         def __init__(self, request, client_address, server):
@@ -106,14 +40,12 @@ class DummyRequestHander(http.server.CGIHTTPRequestHandler):
             Return:
                 True/False
             """
-        manager = FakeServerManager.get_instance()
             func_uri_list = manager._methods[self.command]
             for objChkUrl in func_uri_list:
                 # Check which requested path is in our list.
                 LOG.debug('path for check:%s' % objChkUrl)
                 if(self.path.startswith(objChkUrl)):
                     return True
-
             return False
 
         def _returned_callback(self, path, mock_info):
@@ -148,13 +80,15 @@ class DummyRequestHander(http.server.CGIHTTPRequestHandler):
             if len(response_body_str) > 0:
                 self.wfile.write(response_body_str)
 
-        FakeServerManager.get_instance().add_history(path, RequestHistory(
+            manager.add_history(path, RequestHistory(
                 status_code=status_code,
                 request_headers=request_headers,
                 request_body=request_body,
                 response_headers=copy.deepcopy(mock_headers),
-            response_body=copy.deepcopy(mock_body))
+                response_body=copy.deepcopy(mock_body)))
-        )
+
+            if mock_info.get('content') is None:
+                self.end_headers()
 
         def _parse_request_body(self):
             if 'content-length' not in self.headers:
@@ -201,9 +135,7 @@ class DummyRequestHander(http.server.CGIHTTPRequestHandler):
 
         def do_GET(self):
             """Process GET request"""
-        LOG.debug(
+            LOG.debug('[Start] %s.%s()' % (self.__class__.__name__,
-            '[Start] %s.%s()' %
-            (self.__class__.__name__,
                 inspect.currentframe().f_code.co_name))
 
             # Check URI in request.
@@ -211,7 +143,7 @@ class DummyRequestHander(http.server.CGIHTTPRequestHandler):
                 # Request is registered in our list.
                 tplUri = urlparse(self.path)
                 self._returned_callback(tplUri.path,
-                FakeServerManager.get_instance()._funcs_gets[tplUri.path])
+                    manager._funcs_gets[tplUri.path])
             else:
                 # Unregistered URI is requested
                 LOG.debug('GET Recv. Unknown URL: "%s"' % self.path)
@@ -234,7 +166,7 @@ class DummyRequestHander(http.server.CGIHTTPRequestHandler):
                 # Request is registered in our list.
                 tplUri = urlparse(self.path)
                 self._returned_callback(tplUri.path,
-                FakeServerManager.get_instance()._funcs_posts[tplUri.path])
+                    manager._funcs_posts[tplUri.path])
             else:
                 # Unregistered URI is requested
                 LOG.debug('POST Recv. Unknown URL: "%s"' % self.path)
@@ -249,6 +181,8 @@ class DummyRequestHander(http.server.CGIHTTPRequestHandler):
         def do_PUT(self):
             raise NotImplementedError
 
+    return DummyRequestHandler
+
 
 class RequestHistory:
     """Storage class for storing requested data(Maybe POSTed datas)."""
@@ -268,7 +202,7 @@ class RequestHistory:
         self.response_body = response_body
 
 
-class FakeServerManager(SingletonMixin):
+class FakeServerManager(object):
     """Manager class to manage dummy server setting and control"""
 
     SERVER_PORT = 9990
@@ -347,7 +281,6 @@ class FakeServerManager(SingletonMixin):
             path (str): URI path
             history (RequestHistory): Storage container for each request.
         """
-        with self._rlock:
         if path in self._history:
             self._history[path].append(history)
         else:
@@ -359,7 +292,6 @@ class FakeServerManager(SingletonMixin):
         Args:
             path (str): URI path
         """
-        with self._rlock:
         if not path:
             self._history = {}
             return
@@ -399,8 +331,9 @@ class FakeServerManager(SingletonMixin):
              inspect.currentframe().f_code.co_name))
         while True:
             try:
+                RequestHandler = PrepareRequestHandler(self)
                 self.objHttpd = http.server.HTTPServer(
-                    (address, port), DummyRequestHander)
+                    (address, port), RequestHandler)
             except OSError:
                 time.sleep(self.SERVER_INVOKE_CHECK_INTERVAL)
                 continue

tacker/tests/functional/sol/vnflcm/base.py

@@ -38,7 +38,7 @@ VNF_DELETE_COMPLETION_WAIT = 60
 VNF_HEAL_TIMEOUT = 600
 VNF_LCM_DONE_TIMEOUT = 1200
 RETRY_WAIT_TIME = 5
-FAKE_SERVER_MANAGER = FakeServerManager.get_instance()
+FAKE_SERVER_MANAGER = FakeServerManager()
 FAKE_SERVER_PORT = 9990
 MOCK_NOTIFY_CALLBACK_URL = '/notification/callback'
 UUID_RE = r'\w{8}-\w{4}-\w{4}-\w{4}-\w{12}'

tacker/tests/functional/sol_v2/base_v2.py

@@ -33,7 +33,7 @@ from tacker.tests.functional.sol_v2 import utils
 from tacker.tests import utils as base_utils
 from tacker import version
 
-FAKE_SERVER_MANAGER = FakeServerManager.get_instance()
+FAKE_SERVER_MANAGER = FakeServerManager()
 MOCK_NOTIFY_CALLBACK_URL = '/notification/callback'
 
 LOG = logging.getLogger(__name__)