Don't throw and exception when raise on error is set to false (#293)

* don't throw and exception when raise on error is set to false.

* fix no new line at end of gcp resource detector test file

* make the expected resources value for the same as the default resources

* remove uneeded else

opentelemetry-resourcedetector-gcp/src/opentelemetry/resourcedetector/gcp_resource_detector/__init__.py

@@ -198,6 +198,6 @@ def detect(self) -> "Resource":
                 if found_resources:
                     self.gcp_resources = found_resources
                     break
-        if not self.gcp_resources:
+        if self.raise_on_error and not self.gcp_resources:
             raise NoGoogleResourcesFound()
         return Resource(self.gcp_resources)

opentelemetry-resourcedetector-gcp/tests/test_gcp_resource_detector.py

@@ -526,5 +526,17 @@ def test_resource_finding_fallback(self, getter):
     def test_no_resources_found(self, getter):
         # If no Google resources were found, we throw an exception
         getter.return_value.json.side_effect = Exception
-        resource_finder = GoogleCloudResourceDetector()
+
+        resource_finder = GoogleCloudResourceDetector(raise_on_error=True)
+
         self.assertRaises(NoGoogleResourcesFound, resource_finder.detect)
+
+    def test_detector_dont_raise_on_error(self, getter):
+        # If no Google resources were found, we throw an exception
+        getter.return_value.json.side_effect = Exception
+        detector = GoogleCloudResourceDetector(raise_on_error=False)
+        expected_resources = Resource({})
+
+        resources = detector.detect()
+
+        self.assertEqual(resources, expected_resources)