Add Memory Utilization Metrics and Tests. (#141)

* Add memory utilization percentage metric. #3

* Add tests for memory usage metrics. #3

* Remove use of count dictionary. #3

Author: umaannamalai

newrelic/samplers/memory_usage.py

@@ -16,12 +16,16 @@
 memory usage.
 
 """
+import os
 
-from newrelic.common.system_info import physical_memory_used
+from newrelic.common.system_info import physical_memory_used, total_physical_memory
 
 from newrelic.samplers.decorators import data_source_generator
 
+PID = os.getpid()
+
 
 @data_source_generator(name='Memory Usage')
 def memory_usage_data_source():
-    yield ('Memory/Physical', physical_memory_used())
+    yield ('Memory/Physical/%d' % (PID), physical_memory_used())
+    yield ('Memory/Physical/Utilization/%d' % (PID), physical_memory_used()/total_physical_memory())

tests/agent_unittests/test_memory_metrics.py

@@ -0,0 +1,37 @@
+# Copyright 2010 New Relic, Inc.
+#
+# 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 pytest
+import os
+
+from newrelic.samplers.memory_usage import memory_usage_data_source
+
+@pytest.fixture
+def data_source():
+    sampler = memory_usage_data_source(settings=())["factory"](environ=())
+    yield sampler
+
+PID = os.getpid()
+
+EXPECTED_METRICS = (
+        "Memory/Physical/%d" % PID,
+        "Memory/Physical/Utilization/%d" % PID,
+)
+
+
+def test_gc_metrics_collection(data_source):
+    metrics_table = set(m[0] for m in (data_source() or ()))
+
+    for metric in EXPECTED_METRICS:
+        assert metric in metrics_table