OTLP exporter use grpc runtime cert if not set

exporter/opentelemetry-exporter-otlp/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+## Version 0.16b1
+
+Released 2020-11-26
+
 - Add meter reference to observers
   ([#1425](https://github.com/open-telemetry/opentelemetry-python/pull/1425))
 

exporter/opentelemetry-exporter-otlp/src/opentelemetry/exporter/otlp/exporter.py

@@ -208,11 +208,12 @@ def __init__(
             credentials is None
             and Configuration().EXPORTER_OTLP_CERTIFICATE is None
         ):
-            raise ValueError("No credentials set in secure mode.")
-
-        credentials = credentials or _load_credential_from_file(
-            Configuration().EXPORTER_OTLP_CERTIFICATE
-        )
+            # use the default location chosen by gRPC runtime
+            credentials = ssl_channel_credentials()
+        else:
+            credentials = credentials or _load_credential_from_file(
+                Configuration().EXPORTER_OTLP_CERTIFICATE
+            )
         self._client = self._stub(
             secure_channel(
                 endpoint, credentials, compression=compression_algorithm

exporter/opentelemetry-exporter-otlp/tests/test_otlp_metric_exporter.py

@@ -90,9 +90,17 @@ def test_env_variables(self, mock_exporter_mixin):
         self.assertIsNotNone(kwargs["credentials"])
         self.assertIsInstance(kwargs["credentials"], ChannelCredentials)
 
-    def test_no_credentials_error(self):
-        with self.assertRaises(ValueError):
-            OTLPMetricsExporter()
+    @patch("opentelemetry.exporter.otlp.exporter.ssl_channel_credentials")
+    @patch("opentelemetry.exporter.otlp.exporter.secure_channel")
+    @patch(
+        "opentelemetry.exporter.otlp.metrics_exporter.OTLPMetricsExporter._stub"
+    )
+    # pylint: disable=unused-argument
+    def test_no_credentials_error(
+        self, mock_ssl_channel, mock_secure, mock_stub
+    ):
+        OTLPMetricsExporter(insecure=False)
+        self.assertTrue(mock_ssl_channel.called)
 
     @patch("opentelemetry.sdk.metrics.export.aggregate.time_ns")
     def test_translate_counter_export_record(self, mock_time_ns):

exporter/opentelemetry-exporter-otlp/tests/test_otlp_trace_exporter.py

@@ -187,9 +187,15 @@ def test_env_variables(self, mock_exporter_mixin):
         self.assertIsNotNone(kwargs["credentials"])
         self.assertIsInstance(kwargs["credentials"], ChannelCredentials)
 
-    def test_no_credentials_error(self):
-        with self.assertRaises(ValueError):
-            OTLPSpanExporter()
+    @patch("opentelemetry.exporter.otlp.exporter.ssl_channel_credentials")
+    @patch("opentelemetry.exporter.otlp.exporter.secure_channel")
+    @patch("opentelemetry.exporter.otlp.trace_exporter.OTLPSpanExporter._stub")
+    # pylint: disable=unused-argument
+    def test_no_credentials_error(
+        self, mock_ssl_channel, mock_secure, mock_stub
+    ):
+        OTLPSpanExporter(insecure=False)
+        self.assertTrue(mock_ssl_channel.called)
 
     @patch("opentelemetry.exporter.otlp.exporter.expo")
     @patch("opentelemetry.exporter.otlp.exporter.sleep")