add package common with module utils

The utils module supports finding subclasses of a class. This
is used to find Runner and Scenarios types. utils.py originates from
rally but is stripped down and slightly modified (some dependencies
removed).

Change-Id: Ibc196698e1212899b0836988d0345696b00c5caf
JIRA: -
Signed-off-by: Hans Feldt <hans.feldt@ericsson.com>

2 files changed, 62 insertions, 0 deletions

diff --git a/yardstick/common/__init__.py b/yardstick/common/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/yardstick/common/__init__.py
diff --git a/yardstick/common/utils.py b/yardstick/common/utils.py
new file mode 100644
index 000000000..4de0fcfd5
--- /dev/null
+++ b/yardstick/common/utils.py
@@ -0,0 +1,62 @@
+# Copyright 2013: Mirantis Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+# yardstick comment: this is a modified copy of rally/rally/common/utils.py
+
+import os
+import sys
+from oslo_utils import importutils
+
+import yardstick
+
+
+def itersubclasses(cls, _seen=None):
+    """Generator over all subclasses of a given class in depth first order."""
+
+    if not isinstance(cls, type):
+        raise TypeError("itersubclasses must be called with "
+                        "new-style classes, not %.100r" % cls)
+    _seen = _seen or set()
+    try:
+        subs = cls.__subclasses__()
+    except TypeError:   # fails only when cls is type
+        subs = cls.__subclasses__(cls)
+    for sub in subs:
+        if sub not in _seen:
+            _seen.add(sub)
+            yield sub
+            for sub in itersubclasses(sub, _seen):
+                yield sub
+
+
+def try_append_module(name, modules):
+    if name not in modules:
+        modules[name] = importutils.import_module(name)
+
+
+def import_modules_from_package(package):
+    """Import modules from package and append into sys.modules
+
+    :param: package - Full package name. For example: rally.deploy.engines
+    """
+    path = [os.path.dirname(yardstick.__file__), ".."] + package.split(".")
+    path = os.path.join(*path)
+    for root, dirs, files in os.walk(path):
+        for filename in files:
+            if filename.startswith("__") or not filename.endswith(".py"):
+                continue
+            new_package = ".".join(root.split(os.sep)).split("....")[1]
+            module_name = "%s.%s" % (new_package, filename[:-3])
+            try_append_module(module_name, sys.modules)