Removed many unnecessary uses of dict.keys

This has a few advantages: some of these locations will perform
slightly faster, it's minutely less code, and dict.keys has a different
behavior on Python 3. Also removes usage of dict.iterkeys, which is
identical to just iterating over the dict, except it doesn't exist on
Python 3 at all.

Change-Id: Ia91e97232dc8d78cf63fa807de288fc25cf5425d

swift/account/reaper.py

@@ -267,7 +267,7 @@ class AccountReaper(Daemon):
                 self.stats_objects_possibly_remaining
         if self.stats_return_codes:
             log += _(', return codes: ')
-            for code in sorted(self.stats_return_codes.keys()):
+            for code in sorted(self.stats_return_codes):
                 log += '%s %sxxs, ' % (self.stats_return_codes[code], code)
             log = log[:-2]
         log += _(', elapsed: %.02fs') % (time() - begin)

swift/common/db.py

@@ -50,7 +50,7 @@ def utf8encode(*args):
 
 
 def utf8encodekeys(metadata):
-    uni_keys = [k for k in metadata.keys() if isinstance(k, unicode)]
+    uni_keys = [k for k in metadata if isinstance(k, unicode)]
     for k in uni_keys:
         sv = metadata[k]
         del metadata[k]
@@ -274,7 +274,7 @@ class DatabaseBroker(object):
         timestamp = normalize_timestamp(timestamp)
         # first, clear the metadata
         cleared_meta = {}
-        for k in self.metadata.iterkeys():
+        for k in self.metadata:
             cleared_meta[k] = ('', timestamp)
         self.update_metadata(cleared_meta)
         # then mark the db as deleted

swift/common/memcached.py

@@ -106,7 +106,7 @@ class MemcacheRing(object):
             for i in xrange(NODE_WEIGHT):
                 self._ring[md5hash('%s-%s' % (server, i))] = server
         self._tries = tries if tries <= len(servers) else len(servers)
-        self._sorted = sorted(self._ring.keys())
+        self._sorted = sorted(self._ring)
         self._client_cache = dict(((server, []) for server in servers))
         self._connect_timeout = connect_timeout
         self._io_timeout = io_timeout

swift/common/middleware/bulk.py

@@ -56,7 +56,7 @@ def get_response_body(data_format, data_dict, error_list):
         return json.dumps(data_dict)
     if data_format and data_format.endswith('/xml'):
         output = '<delete>\n'
-        for key in sorted(data_dict.keys()):
+        for key in sorted(data_dict):
             xml_key = key.replace(' ', '_').lower()
             output += '<%s>%s</%s>\n' % (xml_key, data_dict[key], xml_key)
         output += '<errors>\n'
@@ -69,7 +69,7 @@ def get_response_body(data_format, data_dict, error_list):
         return output
 
     output = ''
-    for key in sorted(data_dict.keys()):
+    for key in sorted(data_dict):
         output += '%s: %s\n' % (key, data_dict[key])
     output += 'Errors:\n'
     output += '\n'.join(

swift/common/middleware/ratelimit.py

@@ -25,7 +25,7 @@ from swift.common.swob import Request, Response
 
 def interpret_conf_limits(conf, name_prefix):
     conf_limits = []
-    for conf_key in conf.keys():
+    for conf_key in conf:
         if conf_key.startswith(name_prefix):
             cont_size = int(conf_key[len(name_prefix):])
             rate = float(conf[conf_key])

swift/common/middleware/slo.py

@@ -164,7 +164,7 @@ def parse_input(raw_data):
     req_keys = set(['path', 'etag', 'size_bytes'])
     try:
         for seg_dict in parsed_data:
-            if (set(seg_dict.keys()) != req_keys or
+            if (set(seg_dict) != req_keys or
                     '/' not in seg_dict['path'].lstrip('/')):
                 raise HTTPBadRequest('Invalid SLO Manifest File')
     except (AttributeError, TypeError):

swift/common/ring/ring.py

@@ -171,7 +171,7 @@ class Ring(object):
                 self.tier2devs[tier].append(dev)
 
         tiers_by_length = defaultdict(list)
-        for tier in self.tier2devs.keys():
+        for tier in self.tier2devs:
             tiers_by_length[len(tier)].append(tier)
         self.tiers_by_length = sorted(tiers_by_length.values(),
                                       key=lambda x: len(x[0]))

swift/common/swob.py

@@ -235,7 +235,7 @@ class HeaderEnvironProxy(UserDict.DictMixin):
 
     def keys(self):
         keys = [key[5:].replace('_', '-').title()
-                for key in self.environ.iterkeys() if key.startswith('HTTP_')]
+                for key in self.environ if key.startswith('HTTP_')]
         if 'CONTENT_LENGTH' in self.environ:
             keys.append('Content-Length')
         if 'CONTENT_TYPE' in self.environ:

swift/container/server.py

@@ -406,7 +406,7 @@ class ContainerController(object):
                                   "last_modified"]:
                         SubElement(obj_element, field).text = str(
                             record.pop(field)).decode('utf-8')
-                    for field in sorted(record.keys()):
+                    for field in sorted(record):
                         SubElement(obj_element, field).text = str(
                             record[field]).decode('utf-8')
             ret.body = tostring(doc, encoding='UTF-8').replace(