api/ec2: make the parameter parser an independent method

Following the review, make the parser of argument items
an independent method for readability.

3 files changed, 97 insertions, 89 deletions

diff --git a/nova/api/ec2/apirequest.py b/nova/api/ec2/apirequest.py
index 368d925d8..7d78c5cfa 100644
--- a/nova/api/ec2/apirequest.py
+++ b/nova/api/ec2/apirequest.py
@@ -21,22 +21,15 @@ APIRequest class
 """
 
 import datetime
-import re
 # TODO(termie): replace minidom with etree
 from xml.dom import minidom
 
 from nova import log as logging
+from nova.api.ec2 import ec2utils
 
 LOG = logging.getLogger("nova.api.request")
 
 
-_c2u = re.compile('(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|$)))')
-
-
-def _camelcase_to_underscore(str):
-    return _c2u.sub(r'_\1', str).lower().strip('_')
-
-
 def _underscore_to_camelcase(str):
     return ''.join([x[:1].upper() + x[1:] for x in str.split('_')])
 
@@ -51,59 +44,6 @@ def _database_to_isoformat(datetimeobj):
     return datetimeobj.strftime("%Y-%m-%dT%H:%M:%SZ")
 
 
-def _try_convert(value):
-    """Return a non-string from a string or unicode, if possible.
-
-    ============= =====================================================
-    When value is returns
-    ============= =====================================================
-    zero-length   ''
-    'None'        None
-    'True'        True case insensitive
-    'False'       False case insensitive
-    '0', '-0'     0
-    0xN, -0xN     int from hex (postitive) (N is any number)
-    0bN, -0bN     int from binary (positive) (N is any number)
-    *             try conversion to int, float, complex, fallback value
-
-    """
-    if len(value) == 0:
-        return ''
-    if value == 'None':
-        return None
-    if value.lower() == 'true':
-        return True
-    if value.lower() == 'false':
-        return False
-    valueneg = value[1:] if value[0] == '-' else value
-    if valueneg == '0':
-        return 0
-    if valueneg == '':
-        return value
-    if valueneg[0] == '0':
-        if valueneg[1] in 'xX':
-            return int(value, 16)
-        elif valueneg[1] in 'bB':
-            return int(value, 2)
-        else:
-            try:
-                return int(value, 8)
-            except ValueError:
-                pass
-    try:
-        return int(value)
-    except ValueError:
-        pass
-    try:
-        return float(value)
-    except ValueError:
-        pass
-    try:
-        return complex(value)
-    except ValueError:
-        return value
-
-
 class APIRequest(object):
     def __init__(self, controller, action, version, args):
         self.controller = controller
@@ -114,7 +54,7 @@ class APIRequest(object):
     def invoke(self, context):
         try:
             method = getattr(self.controller,
-                             _camelcase_to_underscore(self.action))
+                             ec2utils.camelcase_to_underscore(self.action))
         except AttributeError:
             controller = self.controller
             action = self.action
@@ -125,32 +65,7 @@ class APIRequest(object):
             #       and reraise as 400 error.
             raise Exception(_error)
 
-        args = {}
-        for key, value in self.args.items():
-            parts = key.split(".")
-            key = _camelcase_to_underscore(parts[0])
-            if isinstance(value, str) or isinstance(value, unicode):
-                # NOTE(vish): Automatically convert strings back
-                #             into their respective values
-                value = _try_convert(value)
-
-                # NOTE(yamahata)
-                # parse multi dot-separted argument.
-                # EBS boot uses multi dot-separeted arguments like
-                # BlockDeviceMapping.1.DeviceName=snap-id
-                # Convert the above into
-                # {'block_device_mapping': {'1': {'device_name': snap-id}}}
-                if len(parts) > 1:
-                    d = args.get(key, {})
-                    args[key] = d
-                    for k in parts[1:-1]:
-                        k = _camelcase_to_underscore(k)
-                        v = d.get(k, {})
-                        d[k] = v
-                        d = v
-                    d[_camelcase_to_underscore(parts[-1])] = value
-                else:
-                    args[key] = value
+        args = ec2utils.dict_from_dotted_str(self.args.items())
 
         for key in args.keys():
             # NOTE(vish): Turn numeric dict keys into lists
diff --git a/nova/api/ec2/ec2utils.py b/nova/api/ec2/ec2utils.py
index 163aa4ed2..3d523016e 100644
--- a/nova/api/ec2/ec2utils.py
+++ b/nova/api/ec2/ec2utils.py
@@ -16,6 +16,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import re
+
 from nova import exception
 
 
@@ -30,3 +32,94 @@ def ec2_id_to_id(ec2_id):
 def id_to_ec2_id(instance_id, template='i-%08x'):
     """Convert an instance ID (int) to an ec2 ID (i-[base 16 number])"""
     return template % instance_id
+
+
+_c2u = re.compile('(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|$)))')
+
+
+def camelcase_to_underscore(str):
+    return _c2u.sub(r'_\1', str).lower().strip('_')
+
+
+def _try_convert(value):
+    """Return a non-string from a string or unicode, if possible.
+
+    ============= =====================================================
+    When value is returns
+    ============= =====================================================
+    zero-length   ''
+    'None'        None
+    'True'        True case insensitive
+    'False'       False case insensitive
+    '0', '-0'     0
+    0xN, -0xN     int from hex (postitive) (N is any number)
+    0bN, -0bN     int from binary (positive) (N is any number)
+    *             try conversion to int, float, complex, fallback value
+
+    """
+    if len(value) == 0:
+        return ''
+    if value == 'None':
+        return None
+    if value.lower() == 'true':
+        return True
+    if value.lower() == 'false':
+        return False
+    valueneg = value[1:] if value[0] == '-' else value
+    if valueneg == '0':
+        return 0
+    if valueneg == '':
+        return value
+    if valueneg[0] == '0':
+        if valueneg[1] in 'xX':
+            return int(value, 16)
+        elif valueneg[1] in 'bB':
+            return int(value, 2)
+        else:
+            try:
+                return int(value, 8)
+            except ValueError:
+                pass
+    try:
+        return int(value)
+    except ValueError:
+        pass
+    try:
+        return float(value)
+    except ValueError:
+        pass
+    try:
+        return complex(value)
+    except ValueError:
+        return value
+
+
+def dict_from_dotted_str(items):
+    """parse multi dot-separated argument into dict.
+    EBS boot uses multi dot-separeted arguments like
+    BlockDeviceMapping.1.DeviceName=snap-id
+    Convert the above into
+    {'block_device_mapping': {'1': {'device_name': snap-id}}}
+    """
+    args = {}
+    for key, value in items:
+        parts = key.split(".")
+        key = camelcase_to_underscore(parts[0])
+        if isinstance(value, str) or isinstance(value, unicode):
+            # NOTE(vish): Automatically convert strings back
+            #             into their respective values
+            value = _try_convert(value)
+
+            if len(parts) > 1:
+                d = args.get(key, {})
+                args[key] = d
+                for k in parts[1:-1]:
+                    k = camelcase_to_underscore(k)
+                    v = d.get(k, {})
+                    d[k] = v
+                    d = v
+                d[camelcase_to_underscore(parts[-1])] = value
+            else:
+                args[key] = value
+
+    return args
diff --git a/nova/tests/test_api.py b/nova/tests/test_api.py
index 7c0331eff..20b20fcbf 100644
--- a/nova/tests/test_api.py
+++ b/nova/tests/test_api.py
@@ -89,7 +89,7 @@ class FakeHttplibConnection(object):
 class XmlConversionTestCase(test.TestCase):
     """Unit test api xml conversion"""
     def test_number_conversion(self):
-        conv = apirequest._try_convert
+        conv = ec2utils._try_convert
         self.assertEqual(conv('None'), None)
         self.assertEqual(conv('True'), True)
         self.assertEqual(conv('False'), False)