Update checked in version of gsutil to version 4.6

gslib/third_party/storage_apitools/util.py

+# Copyright 2014 Google 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.
+"""Assorted utilities shared between parts of apitools."""
+
+import collections
+import httplib
+import os
+import random
+import types
+import urllib2
+
+from gslib.third_party.storage_apitools import exceptions
+
+__all__ = [
+    'DetectGae',
+    'DetectGce',
+]
+
+
+def DetectGae():
+  """Determine whether or not we're running on GAE.
+
+  This is based on:
+    https://developers.google.com/appengine/docs/python/#The_Environment
+
+  Returns:
+    True iff we're running on GAE.
+  """
+  server_software = os.environ.get('SERVER_SOFTWARE', '')
+  return (server_software.startswith('Development/') or
+          server_software.startswith('Google App Engine/'))
+
+
+def DetectGce():
+  """Determine whether or not we're running on GCE.
+
+  This is based on:
+    https://developers.google.com/compute/docs/instances#dmi
+
+  Returns:
+    True iff we're running on a GCE instance.
+  """
+  try:
+    o = urllib2.urlopen('http://metadata.google.internal')
+  except urllib2.URLError:
+    return False
+  return o.getcode() == httplib.OK
+
+
+def NormalizeScopes(scope_spec):
+  """Normalize scope_spec to a set of strings."""
+  if isinstance(scope_spec, types.StringTypes):
+    return set(scope_spec.split(' '))
+  elif isinstance(scope_spec, collections.Iterable):
+    return set(scope_spec)
+  raise exceptions.TypecheckError(
+      'NormalizeScopes expected string or iterable, found %s' % (
+          type(scope_spec),))
+
+
+def Typecheck(arg, arg_type, msg=None):
+  if not isinstance(arg, arg_type):
+    if msg is None:
+      if isinstance(arg_type, tuple):
+        msg = 'Type of arg is "%s", not one of %r' % (type(arg), arg_type)
+      else:
+        msg = 'Type of arg is "%s", not "%s"' % (type(arg), arg_type)
+      raise exceptions.TypecheckError(msg)
+  return arg
+
+
+def CalculateWaitForRetry(retry_attempt, max_wait=60):
+  """Calculates amount of time to wait before a retry attempt.
+
+  Wait time grows exponentially with the number of attempts.
+  A random amount of jitter is added to spread out retry attempts from different
+  clients.
+
+  Args:
+    retry_attempt: Retry attempt counter.
+    max_wait: Upper bound for wait time.
+
+  Returns:
+    Amount of time to wait before retrying request.
+  """
+
+  wait_time = 2 ** retry_attempt
+  max_jitter = (2 ** retry_attempt) / 2
+  return min(wait_time + random.randrange(-max_jitter, max_jitter), max_wait)