fix(opentracer): don't override default ddtrace settings (#2720) (#2724)

* Add regression test

* fix(opentracer): don't override default ddtrace settings

As outlined in #2267, some of the ddtrace default settings were being
overridden as the default opentracer config specified its own overrides.

This patch makes it so that the opentracer doesn't override the ddtrace
defaults.

* Use is

* Fix tests

`_enabled` property was removed as it was unused.

(cherry picked from commit 066a092)

Co-authored-by: Kyle Verhoog <[email protected]>

Author: mergify[bot]

ddtrace/opentracer/tracer.py

@@ -21,11 +21,11 @@
 log = get_logger(__name__)
 
 DEFAULT_CONFIG = {
-    keys.AGENT_HOSTNAME: "localhost",
-    keys.AGENT_HTTPS: False,
-    keys.AGENT_PORT: 8126,
+    keys.AGENT_HOSTNAME: None,
+    keys.AGENT_HTTPS: None,
+    keys.AGENT_PORT: None,
     keys.DEBUG: False,
-    keys.ENABLED: True,
+    keys.ENABLED: None,
     keys.GLOBAL_TAGS: {},
     keys.SAMPLER: None,
     keys.PRIORITY_SAMPLING: None,
@@ -63,7 +63,6 @@ def __init__(self, service_name=None, config=None, scope_manager=None, dd_tracer
             self._config.update(config)
         # Pull out commonly used properties for performance
         self._service_name = service_name or get_application_name()
-        self._enabled = self._config.get(keys.ENABLED)
         self._debug = self._config.get(keys.DEBUG)
 
         if self._debug:
@@ -87,7 +86,7 @@ def __init__(self, service_name=None, config=None, scope_manager=None, dd_tracer
         self._dd_tracer = dd_tracer or ddtrace.tracer or DatadogTracer()
         self._dd_tracer.set_tags(self._config.get(keys.GLOBAL_TAGS))
         self._dd_tracer.configure(
-            enabled=self._enabled,
+            enabled=self._config.get(keys.ENABLED),
             hostname=self._config.get(keys.AGENT_HOSTNAME),
             https=self._config.get(keys.AGENT_HTTPS),
             port=self._config.get(keys.AGENT_PORT),

releasenotes/notes/opentracer-config-4b0422f49f325584.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    opentracer: don't override default tracing config for the `ENABLED`,
+      `AGENT_HOSTNAME`, `AGENT_HTTPS` or `AGENT_PORT` settings.

tests/opentracer/core/test_tracer.py

@@ -10,6 +10,7 @@
 import pytest
 
 import ddtrace
+from ddtrace import Tracer as DDTracer
 from ddtrace.ext.priority import AUTO_KEEP
 from ddtrace.opentracer import Tracer
 from ddtrace.opentracer import set_global_tracer
@@ -25,7 +26,7 @@ def test_config(self):
         tracer = Tracer(service_name="myservice", config=config)
 
         assert tracer._service_name == "myservice"
-        assert tracer._enabled is True
+        assert tracer._dd_tracer.enabled is True
 
     def test_no_service_name(self):
         """A service_name should be generated if one is not provided."""
@@ -44,10 +45,7 @@ def test_multiple_tracer_configs(self):
 
         # Ensure tracer1's config was not mutated
         assert tracer1._service_name == "serv1"
-        assert tracer1._enabled is True
-
         assert tracer2._service_name == "serv2"
-        assert tracer2._enabled is False
 
     def test_invalid_config_key(self):
         """A config with an invalid key should raise a ConfigException."""
@@ -71,6 +69,12 @@ def test_invalid_config_key(self):
             assert ["enabeld", "setttings"] in str(ce_info)
             assert tracer is not None
 
+    def test_ddtrace_fallback_config(self, monkeypatch):
+        """Ensure datadog configuration is used by default."""
+        monkeypatch.setenv("DD_TRACE_ENABLED", "false")
+        tracer = Tracer(dd_tracer=DDTracer())
+        assert tracer._dd_tracer.enabled is False
+
     def test_global_tags(self):
         """Global tags should be passed from the opentracer to the tracer."""
         config = {