Set stackdriver stats exporter user agent (census-instrumentation#370)

* Set stackdriver exporter's user agent

by passing the OC client library version to the cloud monitoring client.

* Include "opencensus" in user agent

Author: c24t

opencensus/stats/exporters/stackdriver_exporter.py

@@ -12,17 +12,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import re
 import os
 import platform
-from . import base
-from google.cloud import monitoring_v3
-from opencensus.stats import aggregation
-from opencensus.stats import measure
+import re
+
 from datetime import datetime
-from opencensus.common.transports import async_
+from google.api_core.gapic_v1 import client_info
+from google.cloud import monitoring_v3
+
+from opencensus.__version__ import __version__
 from opencensus.common.monitored_resource_util.monitored_resource_util \
     import MonitoredResourceUtil
+from opencensus.common.transports import async_
+from opencensus.stats import aggregation
+from opencensus.stats import measure
+from opencensus.stats.exporters import base
 
 MAX_TIME_SERIES_PER_UPLOAD = 200
 OPENCENSUS_TASK_DESCRIPTION = "Opencensus task identifier"
@@ -378,14 +382,20 @@ def set_attribute_label(series, resource_labels, attribute_key,
             label_value_prefix + resource_labels[attribute_key]
 
 
+def get_user_agent_slug():
+    """Get the UA fragment to identify this library version."""
+    return "opencensus-{}".format(__version__)
+
+
 def new_stats_exporter(options):
     """ new_stats_exporter returns an exporter that
         uploads stats data to Stackdriver Monitoring.
     """
     if str(options.project_id).strip() == "":
         raise Exception(ERROR_BLANK_PROJECT_ID)
 
-    client = monitoring_v3.MetricServiceClient()
+    ci = client_info.ClientInfo(client_library_version=get_user_agent_slug())
+    client = monitoring_v3.MetricServiceClient(client_info=ci)
 
     exporter = StackdriverStatsExporter(client=client, options=options)
 

tests/unit/stats/exporter/test_stackdriver_stats.py

@@ -12,15 +12,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from datetime import datetime
 import unittest
+
 import mock
-from datetime import datetime
+
+from opencensus.__version__ import __version__
 from opencensus.stats import aggregation as aggregation_module
-from opencensus.stats.exporters import stackdriver_exporter as stackdriver
 from opencensus.stats import measure as measure_module
 from opencensus.stats import stats as stats_module
 from opencensus.stats import view as view_module
 from opencensus.stats import view_data as view_data_module
+from opencensus.stats.exporters import stackdriver_exporter as stackdriver
 from opencensus.tags import tag_key as tag_key_module
 from opencensus.tags import tag_map as tag_map_module
 from opencensus.tags import tag_value as tag_value_module
@@ -49,11 +52,8 @@
 
 
 class _Client(object):
-    def __init__(self, project=None):
-        if project is None:
-            project = 'PROJECT'
-
-        self.project = project
+    def __init__(self, client_info=None):
+        self.client_info = client_info
 
 
 class TestOptions(unittest.TestCase):
@@ -108,6 +108,28 @@ def test_not_blank_project(self):
 
         self.assertIsInstance(exporter_created, stackdriver.StackdriverStatsExporter)
 
+    def test_get_user_agent_slug(self):
+        self.assertIn(__version__, stackdriver.get_user_agent_slug())
+
+    def test_client_info_user_agent(self):
+        """Check that the monitoring client sets a user agent.
+
+        The user agent should include the library version. Note that this
+        assumes MetricServiceClient calls ClientInfo.to_user_agent to attach
+        the user agent as metadata to metric service API calls.
+        """
+        patch_client = mock.patch(
+            'opencensus.stats.exporters.stackdriver_exporter.monitoring_v3'
+            '.MetricServiceClient',
+            _Client)
+
+        with patch_client:
+            exporter = stackdriver.new_stats_exporter(
+                stackdriver.Options(project_id=1))
+
+        self.assertIn(stackdriver.get_user_agent_slug(),
+                      exporter.client.client_info.to_user_agent())
+
     def test_as_float(self):
         value = 1.5
         result = stackdriver.as_float(value)