Add optional custom properties to logging messages. (#822)

Author: ivaramme

contrib/opencensus-ext-azure/README.rst

@@ -73,6 +73,20 @@ You can enrich the logs with trace IDs and span IDs by using the `logging integr
         logger.warning('In the span')
     logger.warning('After the span')
 
+You can also add custom properties to your log messages in the form of key-values.
+
+WARNING: For this feature to work, you need to pass a dictionary as the argument. If you pass arguments of any other type, the logger will ignore them. The solution is to convert these arguments into a dictionary.
+
+.. code:: python
+
+    import logging
+
+    from opencensus.ext.azure.log_exporter import AzureLogHandler
+
+    logger = logging.getLogger(__name__)
+    logger.addHandler(AzureLogHandler(connection_string='InstrumentationKey=<your-instrumentation_key-here>'))
+    logger.warning('action', {'key-1': 'value-1', 'key-2': 'value2'})
+
 Metrics
 ~~~~~~~
 

contrib/opencensus-ext-azure/examples/logs/properties.py

@@ -0,0 +1,24 @@
+# Copyright 2019, OpenCensus Authors
+#
+# 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 logging
+
+from opencensus.ext.azure.log_exporter import AzureLogHandler
+
+logger = logging.getLogger(__name__)
+# TODO: you need to specify the instrumentation key in a connection string
+# and place it in the APPLICATIONINSIGHTS_CONNECTION_STRING
+# environment variable.
+logger.addHandler(AzureLogHandler())
+logger.warning('action', {'key-1': 'value-1', 'key-2': 'value2'})

contrib/opencensus-ext-azure/opencensus/ext/azure/log_exporter/__init__.py

@@ -198,6 +198,8 @@ def log_record_to_envelope(self, record):
             )
             envelope.data = Data(baseData=data, baseType='ExceptionData')
         else:
+            if isinstance(record.args, dict):
+                properties.update(record.args)
             envelope.name = 'Microsoft.ApplicationInsights.Message'
             data = Message(
                 message=self.format(record),

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

@@ -134,3 +134,34 @@ def test_log_record_to_envelope(self):
             envelope.iKey,
             '12345678-1234-5678-abcd-12345678abcd')
         handler.close()
+
+    @mock.patch('requests.post', return_value=mock.Mock())
+    def test_log_record_with_custom_properties(self, requests_mock):
+        logger = logging.getLogger(self.id())
+        handler = log_exporter.AzureLogHandler(
+            instrumentation_key='12345678-1234-5678-abcd-12345678abcd',
+            storage_path=os.path.join(TEST_FOLDER, self.id()),
+        )
+        logger.addHandler(handler)
+        logger.warning('action', {'key-1': 'value-1', 'key-2': 'value-2'})
+        handler.close()
+        post_body = requests_mock.call_args_list[0][1]['data']
+        self.assertTrue('action' in post_body)
+        self.assertTrue('key-1' in post_body)
+        self.assertTrue('key-2' in post_body)
+
+    @mock.patch('requests.post', return_value=mock.Mock())
+    def test_log_with_invalid_custom_properties(self, requests_mock):
+        logger = logging.getLogger(self.id())
+        handler = log_exporter.AzureLogHandler(
+            instrumentation_key='12345678-1234-5678-abcd-12345678abcd',
+            storage_path=os.path.join(TEST_FOLDER, self.id()),
+        )
+        logger.addHandler(handler)
+        logger.warning('action_1_%s', None)
+        logger.warning('action_2_%s', 'not_a_dict')
+        handler.close()
+        self.assertEqual(len(os.listdir(handler.storage.path)), 0)
+        post_body = requests_mock.call_args_list[0][1]['data']
+        self.assertTrue('action_1' in post_body)
+        self.assertTrue('action_2' in post_body)