exporter/datadog: add support for resource labels and service.name (#1074)

* exporter/datadog: add support for resource labels and service.name

exporter/opentelemetry-exporter-datadog/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add support for span resource labels and service name 
+
 ## Version 0.12b0
 
 Released 2020-08-14

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/constants.py

@@ -6,3 +6,4 @@ SAMPLE_RATE_METRIC_KEY = "_sample_rate"
 SAMPLING_PRIORITY_KEY = "_sampling_priority_v1"
 ENV_KEY = "env"
 VERSION_KEY = "version"
+SERVICE_NAME_TAG = "service.name"

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/exporter.py

@@ -26,7 +26,13 @@ from opentelemetry.sdk.trace.export import SpanExporter, SpanExportResult
 from opentelemetry.trace.status import StatusCanonicalCode
 
 # pylint:disable=relative-beyond-top-level
-from .constants import DD_ORIGIN, ENV_KEY, SAMPLE_RATE_METRIC_KEY, VERSION_KEY
+from .constants import (
+    DD_ORIGIN,
+    ENV_KEY,
+    SAMPLE_RATE_METRIC_KEY,
+    SERVICE_NAME_TAG,
+    VERSION_KEY,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -107,6 +113,7 @@ class DatadogSpanExporter(SpanExporter):
             self.agent_writer.stop()
             self.agent_writer.join(self.agent_writer.exit_timeout)
 
+    # pylint: disable=too-many-locals
     def _translate_to_datadog(self, spans):
         datadog_spans = []
 
@@ -119,10 +126,16 @@ class DatadogSpanExporter(SpanExporter):
             # duration.
             tracer = None
 
+            # extract resource attributes to be used as tags as well as potential service name
+            [
+                resource_tags,
+                resource_service_name,
+            ] = _extract_tags_from_resource(span.resource)
+
             datadog_span = DatadogSpan(
                 tracer,
                 _get_span_name(span),
-                service=self.service,
+                service=resource_service_name or self.service,
                 resource=_get_resource(span),
                 span_type=_get_span_type(span),
                 trace_id=trace_id,
@@ -140,7 +153,12 @@ class DatadogSpanExporter(SpanExporter):
                     datadog_span.set_tag("error.msg", exc_val)
                     datadog_span.set_tag("error.type", exc_type)
 
-            datadog_span.set_tags(span.attributes)
+            # combine resource attributes and span attributes, don't modify existing span attributes
+            combined_span_tags = {}
+            combined_span_tags.update(resource_tags)
+            combined_span_tags.update(span.attributes)
+
+            datadog_span.set_tags(combined_span_tags)
 
             # add configured env tag
             if self.env is not None:
@@ -282,3 +300,19 @@ def _parse_tags_str(tags_str):
             parsed_tags[key] = value
 
     return parsed_tags
+
+
+def _extract_tags_from_resource(resource):
+    """Parse tags from resource.attributes, except service.name which
+    has special significance within datadog"""
+    tags = {}
+    service_name = None
+    if not (resource and getattr(resource, "attributes", None)):
+        return [tags, service_name]
+
+    for attribute_key, attribute_value in resource.attributes.items():
+        if attribute_key == SERVICE_NAME_TAG:
+            service_name = attribute_value
+        else:
+            tags[attribute_key] = attribute_value
+    return [tags, service_name]

exporter/opentelemetry-exporter-datadog/tests/test_datadog_exporter.py

@@ -23,7 +23,7 @@ from ddtrace.internal.writer import AgentWriter
 from opentelemetry import trace as trace_api
 from opentelemetry.exporter import datadog
 from opentelemetry.sdk import trace
-from opentelemetry.sdk.trace import sampling
+from opentelemetry.sdk.trace import Resource, sampling
 from opentelemetry.sdk.util.instrumentation import InstrumentationInfo
 
 
@@ -144,6 +144,17 @@ class TestDatadogSpanExporter(unittest.TestCase):
         # pylint: disable=invalid-name
         self.maxDiff = None
 
+        resource = Resource(
+            attributes={
+                "key_resource": "some_resource",
+                "service.name": "resource_service_name",
+            }
+        )
+
+        resource_without_service = Resource(
+            attributes={"conflicting_key": "conflicting_value"}
+        )
+
         span_names = ("test1", "test2", "test3")
         trace_id = 0x6E0C63257DE34C926F9EFCD03927272E
         trace_id_low = 0x6F9EFCD03927272E
@@ -183,18 +194,25 @@ class TestDatadogSpanExporter(unittest.TestCase):
                 parent=parent_context,
                 kind=trace_api.SpanKind.CLIENT,
                 instrumentation_info=instrumentation_info,
+                resource=Resource({}),
             ),
             trace.Span(
                 name=span_names[1],
                 context=parent_context,
                 parent=None,
                 instrumentation_info=instrumentation_info,
+                resource=resource_without_service,
             ),
             trace.Span(
-                name=span_names[2], context=other_context, parent=None,
+                name=span_names[2],
+                context=other_context,
+                parent=None,
+                resource=resource,
             ),
         ]
 
+        otel_spans[1].set_attribute("conflicting_key", "original_value")
+
         otel_spans[0].start(start_time=start_times[0])
         otel_spans[0].end(end_time=end_times[0])
 
@@ -234,7 +252,12 @@ class TestDatadogSpanExporter(unittest.TestCase):
                 duration=durations[1],
                 error=0,
                 service="test-service",
-                meta={"env": "test", "team": "testers", "version": "0.0.1"},
+                meta={
+                    "env": "test",
+                    "team": "testers",
+                    "version": "0.0.1",
+                    "conflicting_key": "original_value",
+                },
             ),
             dict(
                 trace_id=trace_id_low,
@@ -245,8 +268,13 @@ class TestDatadogSpanExporter(unittest.TestCase):
                 start=start_times[2],
                 duration=durations[2],
                 error=0,
-                service="test-service",
-                meta={"env": "test", "team": "testers", "version": "0.0.1"},
+                service="resource_service_name",
+                meta={
+                    "env": "test",
+                    "team": "testers",
+                    "version": "0.0.1",
+                    "key_resource": "some_resource",
+                },
             ),
         ]