Adding a timestamp converter.

In preparation for parsing the timestamp from the current
operation on create() and update() requests for a cluster.

gcloud_bigtable/_helpers.py

@@ -0,0 +1,42 @@
+# Copyright 2015 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.
+
+"""Utility methods for gcloud_bigtable.
+
+Primarily includes helpers for dealing with low-level
+protobuf objects.
+"""
+
+
+import datetime
+import pytz
+
+
+def _pb_timestamp_to_datetime(timestamp):
+    """Convert a Timestamp protobuf to a datetime object.
+
+    :type timestamp: :class:`._generated.timestamp_pb.Timestamp`
+    :param timestamp: A Google returned timestamp protobuf.
+
+    :rtype: :class:`datetime.datetime`
+    :returns: A UTC datetime object converted from a protobuf timestamp.
+    """
+    naive_dt = (
+        datetime.datetime.utcfromtimestamp(0) +
+        datetime.timedelta(
+            seconds=timestamp.seconds,
+            microseconds=(timestamp.nanos / 1000.0),
+        )
+    )
+    return naive_dt.replace(tzinfo=pytz.utc)

gcloud_bigtable/test__helpers.py

@@ -0,0 +1,37 @@
+# Copyright 2015 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.
+
+
+import unittest2
+
+
+class Test__pb_timestamp_to_datetime(unittest2.TestCase):
+
+    def _callFUT(self, timestamp):
+        from gcloud_bigtable._helpers import _pb_timestamp_to_datetime
+        return _pb_timestamp_to_datetime(timestamp)
+
+    def test_it(self):
+        import datetime
+        import pytz
+        from gcloud_bigtable._generated.timestamp_pb2 import Timestamp
+
+        # Epoch is midnight on January 1, 1970 ...
+        dt_stamp = datetime.datetime(1970, month=1, day=1, hour=0,
+                                     minute=1, second=1, microsecond=1234,
+                                     tzinfo=pytz.utc)
+        # ... so 1 minute and 1 second after is 61 seconds and 1234
+        # microseconds is 1234000 nanoseconds.
+        timestamp = Timestamp(seconds=61, nanos=1234000)
+        self.assertEqual(self._callFUT(timestamp), dt_stamp)

setup.py

@@ -14,6 +14,7 @@
     'httplib2 >= 0.9.1',
     'oauth2client >= 1.4.6',
     'protobuf >= 3.0.0a3',
+    'pytz',
     'six >= 1.6.1',
 ]