Standard Metrics - Processor Time (#720)

Author: lzchen

contrib/opencensus-ext-azure/README.rst

@@ -152,6 +152,8 @@ The exporter also includes a set of standard metrics that are exported to Azure
 Below is a list of standard metrics that are currently available:
 
 - Available memory (bytes)
+- CPU Processor Time (percentage)
+- Process private bytes (bytes)
 
 Trace
 ~~~~~

contrib/opencensus-ext-azure/opencensus/ext/azure/metrics_exporter/standard_metrics.py

@@ -15,6 +15,7 @@
 import logging
 import psutil
 
+from opencensus.metrics.export.gauge import DerivedDoubleGauge
 from opencensus.metrics.export.gauge import DerivedLongGauge
 from opencensus.metrics.export.gauge import Registry
 from opencensus.metrics.export.metric_producer import MetricProducer
@@ -25,6 +26,7 @@
 # Namespaces used in Azure Monitor
 AVAILABLE_MEMORY = "\\Memory\\Available Bytes"
 PRIVATE_BYTES = "\\Process(??APP_WIN32_PROC??)\\Private Bytes"
+PROCESSOR_TIME = "\\Processor(_Total)\\% Processor Time"
 
 
 def get_available_memory():
@@ -75,6 +77,36 @@ def get_process_private_bytes_metric():
     return gauge
 
 
+def get_processor_time():
+    cpu_times_percent = psutil.cpu_times_percent()
+    return 100 - cpu_times_percent.idle
+
+
+def get_processor_time_metric():
+    """ Returns a derived gauge for the processor time.
+
+    Processor time is defined as a float representing the current system
+    wide CPU utilization minus idle CPU time as a percentage. Idle CPU
+    time is defined as the time spent doing nothing. Return values range
+    from 0.0 to 100.0 inclusive.
+
+    :rtype: :class:`opencensus.metrics.export.gauge.DerivedDoubleGauge`
+    :return: The gauge representing the processor time metric
+    """
+    gauge = DerivedDoubleGauge(
+        PROCESSOR_TIME,
+        'Processor time as a percentage',
+        'percentage',
+        [])
+    gauge.create_default_time_series(get_processor_time)
+    # From the psutil docs: the first time this method is called with interval
+    # = None it will return a meaningless 0.0 value which you are supposed to
+    # ignore. Call cpu_percent() once so that the subsequent calls from the
+    # gauge will be meaningful.
+    psutil.cpu_times_percent()
+    return gauge
+
+
 class AzureStandardMetricsProducer(MetricProducer):
     """Implementation of the producer of standard metrics.
 
@@ -85,6 +117,7 @@ def __init__(self):
         self.registry = Registry()
         self.registry.add_gauge(get_available_memory_metric())
         self.registry.add_gauge(get_process_private_bytes_metric())
+        self.registry.add_gauge(get_processor_time_metric())
 
     def get_metrics(self):
         return self.registry.get_metrics()

contrib/opencensus-ext-azure/tests/test_azure_standard_metrics.py

@@ -31,7 +31,7 @@ def test_producer_get_metrics(self):
         producer = standard_metrics.AzureStandardMetricsProducer()
         metrics = producer.get_metrics()
 
-        self.assertEqual(len(metrics), 2)
+        self.assertEqual(len(metrics), 3)
 
     def test_get_available_memory_metric(self):
         gauge = standard_metrics.get_available_memory_metric()
@@ -73,3 +73,18 @@ def test_get_process_private_bytes_exception(self, logger_mock):
             standard_metrics.get_process_private_bytes()
 
             logger_mock.exception.assert_called()
+
+    def test_get_processor_time_metric(self):
+        gauge = standard_metrics.get_processor_time_metric()
+
+        self.assertEqual(gauge.descriptor.name,
+                         '\\Processor(_Total)\\% Processor Time')
+
+    def test_get_processor_time(self):
+        with mock.patch('psutil.cpu_times_percent') as processor_mock:
+            cpu = collections.namedtuple('cpu', 'idle')
+            cpu_times = cpu(idle=94.5)
+            processor_mock.return_value = cpu_times
+            processor_time = standard_metrics.get_processor_time()
+
+            self.assertEqual(processor_time, 5.5)