Merge "Expose Znode Stats and Capabilities"

tooz/coordination.py

@@ -292,6 +292,19 @@ class CoordinationDriver(object):
         """
         raise tooz.NotImplemented
 
+    @staticmethod
+    def get_member_info(group_id, member_id):
+        """Return the statistics and capabilities of a member asynchronously.
+
+        :param group_id: the id of the group of the member
+        :type group_id: str
+        :param member_id: the id of the member
+        :type member_id: str
+        :returns: capabilities and statistics of a member
+        :rtype: CoordAsyncResult
+        """
+        raise tooz.NotImplemented
+
     @staticmethod
     def update_capabilities(group_id, capabilities):
         """Update capabilities of the caller in the specified group

tooz/drivers/zookeeper.py

@@ -278,6 +278,39 @@ class BaseZooKeeperDriver(coordination.CoordinationDriver):
                               timeout_exception=self._timeout_exception,
                               group_id=group_id, member_id=self._member_id)
 
+    @classmethod
+    def _get_member_info_handler(cls, async_result, timeout,
+                                 timeout_exception, group_id,
+                                 member_id):
+        try:
+            capabilities, znode_stats = async_result.get(block=True,
+                                                         timeout=timeout)
+        except timeout_exception as e:
+            coordination.raise_with_cause(coordination.OperationTimedOut,
+                                          utils.exception_message(e),
+                                          cause=e)
+        except exceptions.NoNodeError:
+            raise coordination.MemberNotJoined(group_id, member_id)
+        except exceptions.ZookeeperError as e:
+            coordination.raise_with_cause(coordination.ToozError,
+                                          utils.exception_message(e),
+                                          cause=e)
+        else:
+            member_info = {
+                'capabilities': cls._loads(capabilities),
+                'created_at': utils.millis_to_datetime(znode_stats.ctime),
+                'updated_at': utils.millis_to_datetime(znode_stats.mtime)
+            }
+            return member_info
+
+    def get_member_info(self, group_id, member_id):
+        member_path = self._path_member(group_id, member_id)
+        async_result = self._coord.get_async(member_path)
+        return ZooAsyncResult(async_result,
+                              self._get_member_info_handler,
+                              timeout_exception=self._timeout_exception,
+                              group_id=group_id, member_id=self._member_id)
+
     @staticmethod
     def _get_groups_handler(async_result, timeout, timeout_exception):
         try:

tooz/tests/test_coordination.py

@@ -226,6 +226,7 @@ class TestAPI(testscenarios.TestWithScenarios,
         capa = self._coord.get_member_capabilities(self.group_id,
                                                    self.member_id).get()
         self.assertEqual(capa, caps)
+        self.assertEqual(capa['type'], caps['type'])
 
     def test_get_member_capabilities_nonexistent_group(self):
         capa = self._coord.get_member_capabilities(self.group_id,
@@ -242,6 +243,44 @@ class TestAPI(testscenarios.TestWithScenarios,
         self.assertRaises(tooz.coordination.MemberNotJoined,
                           capa.get)
 
+    def test_get_member_info(self):
+        self._coord.create_group(self.group_id).get()
+        self._coord.join_group(self.group_id, b"test_capabilities")
+
+        member_info = self._coord.get_member_info(self.group_id,
+                                                  self.member_id).get()
+        self.assertEqual(member_info['capabilities'], b"test_capabilities")
+
+    def test_get_member_info_complex(self):
+        self._coord.create_group(self.group_id).get()
+        caps = {
+            'type': 'warrior',
+            'abilities': ['fight', 'flight', 'double-hit-damage'],
+        }
+        member_info = {'capabilities': 'caps',
+                       'created_at': '0',
+                       'updated_at': '0'}
+        self._coord.join_group(self.group_id, caps)
+        member_info = self._coord.get_member_info(self.group_id,
+                                                  self.member_id).get()
+        self.assertEqual(member_info['capabilities'], caps)
+
+    def test_get_member_info_nonexistent_group(self):
+        member_info = self._coord.get_member_info(self.group_id,
+                                                  self.member_id)
+        # Drivers raise one of those depending on their capability
+        self.assertRaisesAny([tooz.coordination.MemberNotJoined,
+                              tooz.coordination.GroupNotCreated],
+                             member_info.get)
+
+    def test_get_member_info_nonjoined_member(self):
+        self._coord.create_group(self.group_id).get()
+        member_id = self._get_random_uuid()
+        member_info = self._coord.get_member_info(self.group_id,
+                                                  member_id)
+        self.assertRaises(tooz.coordination.MemberNotJoined,
+                          member_info.get)
+
     def test_update_capabilities(self):
         self._coord.create_group(self.group_id).get()
         self._coord.join_group(self.group_id, b"test_capabilities1").get()

tooz/utils.py

@@ -14,6 +14,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import datetime
 import errno
 import os
 
@@ -175,3 +176,8 @@ def loads(blob, excp_cls=coordination.SerializationError):
     except (msgpack.UnpackException, ValueError) as e:
         coordination.raise_with_cause(excp_cls, exception_message(e),
                                       cause=e)
+
+
+def millis_to_datetime(milliseconds):
+    """Converts number of milliseconds (from epoch) into a datetime object."""
+    return datetime.datetime.fromtimestamp(float(milliseconds) / 1000)