Standard Metrics - Process CPU Usage (#722)

Author: lzchen

contrib/opencensus-ext-azure/README.rst

@@ -153,6 +153,7 @@ Below is a list of standard metrics that are currently available:
 
 - Available memory (bytes)
 - CPU Processor Time (percentage)
+- Process CPU Usage (percentage)
 - Process private bytes (bytes)
 
 Trace

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

@@ -21,12 +21,13 @@
 from opencensus.metrics.export.metric_producer import MetricProducer
 
 logger = logging.getLogger(__name__)
-
+PROCESS = psutil.Process()
 
 # Namespaces used in Azure Monitor
 AVAILABLE_MEMORY = "\\Memory\\Available Bytes"
 PRIVATE_BYTES = "\\Process(??APP_WIN32_PROC??)\\Private Bytes"
 PROCESSOR_TIME = "\\Processor(_Total)\\% Processor Time"
+PROCESS_TIME = "\\Process(??APP_WIN32_PROC??)\\% Processor Time"
 
 
 def get_available_memory():
@@ -53,8 +54,7 @@ def get_available_memory_metric():
 
 def get_process_private_bytes():
     try:
-        process = psutil.Process()
-        return process.memory_info().rss
+        return PROCESS.memory_info().rss
     except Exception:
         logger.exception('Error handling get process private bytes.')
 
@@ -77,6 +77,39 @@ def get_process_private_bytes_metric():
     return gauge
 
 
+def get_process_cpu_usage():
+    try:
+        # In the case of a process running on multiple threads on different CPU
+        # cores, the returned value of cpu_percent() can be > 100.0. We
+        # normalize the cpu process using the number of logical CPUs
+        cpu_count = psutil.cpu_count(logical=True)
+        return PROCESS.cpu_percent() / cpu_count
+    except Exception:
+        logger.exception('Error handling get process cpu usage.')
+
+
+def get_process_cpu_usage_metric():
+    """ Returns a derived gauge for the CPU usage for the current process.
+
+    Return values range from 0.0 to 100.0 inclusive.
+
+    :rtype: :class:`opencensus.metrics.export.gauge.DerivedDoubleGauge`
+    :return: The gauge representing the process cpu usage metric
+    """
+    gauge = DerivedDoubleGauge(
+        PROCESS_TIME,
+        'Processor time as a percentage',
+        'percentage',
+        [])
+    gauge.create_default_time_series(get_process_cpu_usage)
+    # 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() with process once so that the subsequent calls
+    # from the gauge will be meaningful.
+    PROCESS.cpu_percent()
+    return gauge
+
+
 def get_processor_time():
     cpu_times_percent = psutil.cpu_times_percent()
     return 100 - cpu_times_percent.idle
@@ -117,6 +150,7 @@ 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_process_cpu_usage_metric())
         self.registry.add_gauge(get_processor_time_metric())
 
     def get_metrics(self):

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), 3)
+        self.assertEqual(len(metrics), 4)
 
     def test_get_available_memory_metric(self):
         gauge = standard_metrics.get_available_memory_metric()
@@ -55,21 +55,21 @@ def test_get_process_private_bytes_metric(self):
                          '\\Process(??APP_WIN32_PROC??)\\Private Bytes')
 
     def test_get_process_private_bytes(self):
-        with mock.patch('psutil.Process') as process_mock:
+        with mock.patch('opencensus.ext.azure.metrics_exporter' +
+                        '.standard_metrics.PROCESS') as process_mock:
             memory = collections.namedtuple('memory', 'rss')
             pmem = memory(rss=100)
-            process = mock.Mock()
-            process.memory_info.return_value = pmem
-            process_mock.return_value = process
+            process_mock.memory_info.return_value = pmem
             mem = standard_metrics.get_process_private_bytes()
 
             self.assertEqual(mem, 100)
 
     @mock.patch('opencensus.ext.azure.metrics_exporter'
                 '.standard_metrics.logger')
     def test_get_process_private_bytes_exception(self, logger_mock):
-        with mock.patch('psutil.Process') as process_mock:
-            process_mock.side_effect = Exception()
+        with mock.patch('opencensus.ext.azure.metrics_exporter' +
+                        '.standard_metrics.PROCESS') as process_mock:
+            process_mock.memory_info.side_effect = Exception()
             standard_metrics.get_process_private_bytes()
 
             logger_mock.exception.assert_called()
@@ -88,3 +88,30 @@ def test_get_processor_time(self):
             processor_time = standard_metrics.get_processor_time()
 
             self.assertEqual(processor_time, 5.5)
+
+    def test_get_process_cpu_usage_metric(self):
+        gauge = standard_metrics.get_process_cpu_usage_metric()
+
+        self.assertEqual(gauge.descriptor.name,
+                         '\\Process(??APP_WIN32_PROC??)\\% Processor Time')
+
+    def test_get_process_cpu_usage(self):
+        with mock.patch('opencensus.ext.azure.metrics_exporter' +
+                        '.standard_metrics.PROCESS') as process_mock:
+            with mock.patch('opencensus.ext.azure.metrics_exporter' +
+                            '.standard_metrics.psutil') as psutil_mock:
+                process_mock.cpu_percent.return_value = 44.4
+                psutil_mock.cpu_count.return_value = 2
+                cpu_usage = standard_metrics.get_process_cpu_usage()
+
+                self.assertEqual(cpu_usage, 22.2)
+
+    @mock.patch('opencensus.ext.azure.metrics_exporter'
+                '.standard_metrics.logger')
+    def test_get_process_cpu_usage_exception(self, logger_mock):
+        with mock.patch('opencensus.ext.azure.metrics_exporter' +
+                        '.standard_metrics.psutil') as psutil_mock:
+            psutil_mock.cpu_count.return_value = None
+            standard_metrics.get_process_cpu_usage()
+
+            logger_mock.exception.assert_called()