Removing use of pytz module / implementing our own UTC.

gcloud/_helpers.py

@@ -15,6 +15,8 @@
 
 This module is not part of the public API surface of `gcloud`.
 """
+
+import datetime
 import os
 import socket
 
@@ -75,6 +77,41 @@ def top(self):
             return self._stack[-1]
 
 
+class _UTC(datetime.tzinfo):
+    """Basic UTC implementation.
+
+    Implementing a small surface area to avoid depending on ``pytz``.
+    """
+
+    _dst = datetime.timedelta(0)
+    _tzname = 'UTC'
+    _utcoffset = _dst
+
+    def dst(self, dt):  # pylint: disable=unused-argument
+        """Daylight savings time offset."""
+        return self._dst
+
+    def fromutc(self, dt):
+        """Convert a timestamp from (naive) UTC to this timezone."""
+        if dt.tzinfo is None:
+            return dt.replace(tzinfo=self)
+        return super(_UTC, self).fromutc(dt)
+
+    def tzname(self, dt):  # pylint: disable=unused-argument
+        """Get the name of this timezone."""
+        return self._tzname
+
+    def utcoffset(self, dt):  # pylint: disable=unused-argument
+        """UTC offset of this timezone."""
+        return self._utcoffset
+
+    def __repr__(self):
+        return '<%s>' % (self._tzname,)
+
+    def __str__(self):
+        return self._tzname
+
+
 def _ensure_tuple_or_list(arg_name, tuple_or_list):
     """Ensures an input is a tuple or list.
 
@@ -168,3 +205,9 @@ def _determine_default_project(project=None):
         project = _get_production_project()
 
     return project
+
+
+try:
+    from pytz import UTC  # pylint: disable=unused-import
+except ImportError:
+    UTC = _UTC()  # Singleton instance to be used throughout.

gcloud/bigquery/_helpers.py

@@ -18,9 +18,10 @@
 import datetime
 import sys
 
-import pytz
+from gcloud._helpers import UTC
 
-_EPOCH = datetime.datetime.utcfromtimestamp(0).replace(tzinfo=pytz.utc)
+
+_EPOCH = datetime.datetime.utcfromtimestamp(0).replace(tzinfo=UTC)
 
 
 def _millis(when):
@@ -62,7 +63,7 @@ def _prop_from_datetime(value):
     if value is not None:
         if value.tzinfo is None:
             # Assume UTC
-            value = value.replace(tzinfo=pytz.utc)
+            value = value.replace(tzinfo=UTC)
         # back-end wants timestamps as milliseconds since the epoch
         return _millis(value)
 

gcloud/bigquery/test__helpers.py

@@ -23,8 +23,9 @@ def _callFUT(self, value):
 
     def test_one_second_from_epoch(self):
         import datetime
-        import pytz
-        WHEN = datetime.datetime(1970, 1, 1, 0, 0, 1, tzinfo=pytz.utc)
+        from gcloud._helpers import UTC
+
+        WHEN = datetime.datetime(1970, 1, 1, 0, 0, 1, tzinfo=UTC)
         self.assertEqual(self._callFUT(WHEN), 1000)
 
 
@@ -39,11 +40,12 @@ def test_w_none(self):
 
     def test_w_millis(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _total_seconds
+
         NOW = datetime.datetime(2015, 7, 29, 17, 45, 21, 123456,
-                                tzinfo=pytz.utc)
-        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=pytz.utc)
+                                tzinfo=UTC)
+        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=UTC)
         MILLIS = _total_seconds(NOW - EPOCH) * 1000
         self.assertEqual(self._callFUT(MILLIS), NOW)
 
@@ -59,34 +61,42 @@ def test_w_none(self):
 
     def test_w_utc_datetime(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _total_seconds
-        NOW = datetime.datetime.utcnow().replace(tzinfo=pytz.utc)
-        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=pytz.utc)
+
+        NOW = datetime.datetime.utcnow().replace(tzinfo=UTC)
+        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=UTC)
         MILLIS = int(_total_seconds(NOW - EPOCH) * 1000)
         result = self._callFUT(NOW)
         self.assertTrue(isinstance(result, int))
         self.assertEqual(result, MILLIS)
 
     def test_w_non_utc_datetime(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
+        from gcloud._helpers import _UTC
         from gcloud.bigquery._helpers import _total_seconds
-        eastern = pytz.timezone('US/Eastern')
-        NOW = datetime.datetime(2015, 7, 28, 16, 34, 47, tzinfo=eastern)
-        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=pytz.utc)
+
+        class CET(_UTC):
+            _tzname = 'CET'
+            _utcoffset = datetime.timedelta(hours=-1)
+
+        zone = CET()
+        NOW = datetime.datetime(2015, 7, 28, 16, 34, 47, tzinfo=zone)
+        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=UTC)
         MILLIS = int(_total_seconds(NOW - EPOCH) * 1000)
         result = self._callFUT(NOW)
         self.assertTrue(isinstance(result, int))
         self.assertEqual(result, MILLIS)
 
     def test_w_naive_datetime(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _total_seconds
+
         NOW = datetime.datetime.utcnow()
-        UTC_NOW = NOW.replace(tzinfo=pytz.utc)
-        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=pytz.utc)
+        UTC_NOW = NOW.replace(tzinfo=UTC)
+        EPOCH = datetime.datetime(1970, 1, 1, tzinfo=UTC)
         MILLIS = int(_total_seconds(UTC_NOW - EPOCH) * 1000)
         result = self._callFUT(NOW)
         self.assertTrue(isinstance(result, int))

gcloud/bigquery/test_dataset.py

@@ -28,10 +28,11 @@ def _makeOne(self, *args, **kw):
 
     def _makeResource(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
+
         self.WHEN_TS = 1437767599.006
         self.WHEN = datetime.datetime.utcfromtimestamp(self.WHEN_TS).replace(
-            tzinfo=pytz.UTC)
+            tzinfo=UTC)
         self.ETAG = 'ETAG'
         self.DS_ID = '%s:%s' % (self.PROJECT, self.DS_NAME)
         self.RESOURCE_URL = 'http://example.com/path/to/resource'

gcloud/bigquery/test_table.py

@@ -76,10 +76,11 @@ def _makeOne(self, *args, **kw):
 
     def _makeResource(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
+
         self.WHEN_TS = 1437767599.006
         self.WHEN = datetime.datetime.utcfromtimestamp(self.WHEN_TS).replace(
-            tzinfo=pytz.UTC)
+            tzinfo=UTC)
         self.ETAG = 'ETAG'
         self.TABLE_ID = '%s:%s:%s' % (
             self.PROJECT, self.DS_NAME, self.TABLE_NAME)
@@ -206,10 +207,11 @@ def test_schema_setter(self):
 
     def test_props_set_by_server(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _millis
-        CREATED = datetime.datetime(2015, 7, 29, 12, 13, 22, tzinfo=pytz.utc)
-        MODIFIED = datetime.datetime(2015, 7, 29, 14, 47, 15, tzinfo=pytz.utc)
+
+        CREATED = datetime.datetime(2015, 7, 29, 12, 13, 22, tzinfo=UTC)
+        MODIFIED = datetime.datetime(2015, 7, 29, 14, 47, 15, tzinfo=UTC)
         TABLE_ID = '%s:%s:%s' % (
             self.PROJECT, self.DS_NAME, self.TABLE_NAME)
         URL = 'http://example.com/projects/%s/datasets/%s/tables/%s' % (
@@ -258,8 +260,9 @@ def test_expires_setter_bad_value(self):
 
     def test_expires_setter(self):
         import datetime
-        import pytz
-        WHEN = datetime.datetime(2015, 7, 28, 16, 39, tzinfo=pytz.utc)
+        from gcloud._helpers import UTC
+
+        WHEN = datetime.datetime(2015, 7, 28, 16, 39, tzinfo=UTC)
         client = _Client(self.PROJECT)
         dataset = _Dataset(client)
         table = self._makeOne(self.TABLE_NAME, dataset)
@@ -443,9 +446,10 @@ def test_create_w_bound_client(self):
 
     def test_create_w_alternate_client(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery.table import SchemaField
         from gcloud.bigquery._helpers import _millis
+
         PATH = 'projects/%s/datasets/%s/tables' % (self.PROJECT, self.DS_NAME)
         DESCRIPTION = 'DESCRIPTION'
         TITLE = 'TITLE'
@@ -454,7 +458,7 @@ def test_create_w_alternate_client(self):
         RESOURCE['description'] = DESCRIPTION
         RESOURCE['friendlyName'] = TITLE
         self.EXP_TIME = datetime.datetime(2015, 8, 1, 23, 59, 59,
-                                          tzinfo=pytz.utc)
+                                          tzinfo=UTC)
         RESOURCE['expirationTime'] = _millis(self.EXP_TIME)
         RESOURCE['view'] = {}
         RESOURCE['view']['query'] = QUERY
@@ -642,9 +646,10 @@ def test_patch_w_bound_client(self):
 
     def test_patch_w_alternate_client(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _millis
         from gcloud.bigquery.table import SchemaField
+
         PATH = 'projects/%s/datasets/%s/tables/%s' % (
             self.PROJECT, self.DS_NAME, self.TABLE_NAME)
         QUERY = 'select fullname, age from person_ages'
@@ -654,7 +659,7 @@ def test_patch_w_alternate_client(self):
         RESOURCE['type'] = 'VIEW'
         RESOURCE['location'] = LOCATION
         self.EXP_TIME = datetime.datetime(2015, 8, 1, 23, 59, 59,
-                                          tzinfo=pytz.utc)
+                                          tzinfo=UTC)
         RESOURCE['expirationTime'] = _millis(self.EXP_TIME)
         conn1 = _Connection()
         client1 = _Client(project=self.PROJECT, connection=conn1)
@@ -750,9 +755,10 @@ def test_update_w_bound_client(self):
 
     def test_update_w_alternate_client(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _millis
         from gcloud.bigquery.table import SchemaField
+
         PATH = 'projects/%s/datasets/%s/tables/%s' % (
             self.PROJECT, self.DS_NAME, self.TABLE_NAME)
         DEF_TABLE_EXP = 12345
@@ -762,7 +768,7 @@ def test_update_w_alternate_client(self):
         RESOURCE['defaultTableExpirationMs'] = 12345
         RESOURCE['location'] = LOCATION
         self.EXP_TIME = datetime.datetime(2015, 8, 1, 23, 59, 59,
-                                          tzinfo=pytz.utc)
+                                          tzinfo=UTC)
         RESOURCE['expirationTime'] = _millis(self.EXP_TIME)
         RESOURCE['view'] = {'query': QUERY}
         RESOURCE['type'] = 'VIEW'
@@ -837,14 +843,15 @@ def test_delete_w_alternate_client(self):
 
     def test_fetch_data_w_bound_client(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery.table import SchemaField
         from gcloud.bigquery._helpers import _prop_from_datetime
+
         PATH = 'projects/%s/datasets/%s/tables/%s/data' % (
             self.PROJECT, self.DS_NAME, self.TABLE_NAME)
         WHEN_TS = 1437767599.006
         WHEN = datetime.datetime.utcfromtimestamp(WHEN_TS).replace(
-            tzinfo=pytz.UTC)
+            tzinfo=UTC)
         WHEN_1 = WHEN + datetime.timedelta(seconds=1)
         WHEN_2 = WHEN + datetime.timedelta(seconds=2)
         ROWS = 1234
@@ -1068,12 +1075,13 @@ def test_fetch_data_w_record_schema(self):
 
     def test_insert_data_w_bound_client(self):
         import datetime
-        import pytz
+        from gcloud._helpers import UTC
         from gcloud.bigquery._helpers import _prop_from_datetime
         from gcloud.bigquery.table import SchemaField
+
         WHEN_TS = 1437767599.006
         WHEN = datetime.datetime.utcfromtimestamp(WHEN_TS).replace(
-            tzinfo=pytz.UTC)
+            tzinfo=UTC)
         PATH = 'projects/%s/datasets/%s/tables/%s/insertAll' % (
             self.PROJECT, self.DS_NAME, self.TABLE_NAME)
         conn = _Connection({})

gcloud/credentials.py

@@ -27,7 +27,6 @@
 from oauth2client.client import _get_application_default_credential_from_file
 from oauth2client import crypt
 from oauth2client import service_account
-import pytz
 
 try:
     from google.appengine.api import app_identity
@@ -40,6 +39,8 @@
     class _GAECreds(object):
         """Dummy class if not in App Engine environment."""
 
+from gcloud._helpers import UTC
+
 
 def get_credentials():
     """Gets credentials implicitly from the current environment.
@@ -274,17 +275,17 @@ def _get_expiration_seconds(expiration):
     """
     # If it's a timedelta, add it to `now` in UTC.
     if isinstance(expiration, datetime.timedelta):
-        now = _utcnow().replace(tzinfo=pytz.utc)
+        now = _utcnow().replace(tzinfo=UTC)
         expiration = now + expiration
 
     # If it's a datetime, convert to a timestamp.
     if isinstance(expiration, datetime.datetime):
         # Make sure the timezone on the value is UTC
         # (either by converting or replacing the value).
         if expiration.tzinfo:
-            expiration = expiration.astimezone(pytz.utc)
+            expiration = expiration.astimezone(UTC)
         else:
-            expiration = expiration.replace(tzinfo=pytz.utc)
+            expiration = expiration.replace(tzinfo=UTC)
 
         # Turn the datetime into a timestamp (seconds, not microseconds).
         expiration = int(calendar.timegm(expiration.timetuple()))

gcloud/datastore/helpers.py

@@ -21,9 +21,9 @@
 import datetime
 
 from google.protobuf.internal.type_checkers import Int64ValueChecker
-import pytz
 import six
 
+from gcloud._helpers import UTC
 from gcloud.datastore import _datastore_v1_pb2 as datastore_pb
 from gcloud.datastore.entity import Entity
 from gcloud.datastore.key import Key
@@ -185,9 +185,9 @@ def _pb_attr_value(val):
         # If the datetime is naive (no timezone), consider that it was
         # intended to be UTC and replace the tzinfo to that effect.
         if not val.tzinfo:
-            val = val.replace(tzinfo=pytz.utc)
+            val = val.replace(tzinfo=UTC)
         # Regardless of what timezone is on the value, convert it to UTC.
-        val = val.astimezone(pytz.utc)
+        val = val.astimezone(UTC)
         # Convert the datetime to a microsecond timestamp.
         value = int(calendar.timegm(val.timetuple()) * 1e6) + val.microsecond
     elif isinstance(val, Key):
@@ -233,7 +233,7 @@ def _get_value_from_value_pb(value_pb):
         microseconds = value_pb.timestamp_microseconds_value
         naive = (datetime.datetime.utcfromtimestamp(0) +
                  datetime.timedelta(microseconds=microseconds))
-        result = naive.replace(tzinfo=pytz.utc)
+        result = naive.replace(tzinfo=UTC)
 
     elif value_pb.HasField('key_value'):
         result = key_from_protobuf(value_pb.key_value)