fix(debugging): ensure dynamic instrumentation enabled

With the introduction of exception debugging, the new enablement
logic caused the dynamic instrumentation to not register with the
remoteconfig client when the programmatic API was used, unless
DD_DYNAMIC_INSTRUMENTATION_ENABLED is also set. Since this is not
the documented behaviour, we make this fix to align with the
expected behaviour of the programmatic API.

ddtrace/debugging/_debugger.py

@@ -186,6 +186,8 @@ def enable(cls, run_module=False):
 
         log.debug("Enabling %s", cls.__name__)
 
+        di_config.enabled = True
+
         cls.__watchdog__.install()
 
         if di_config.metrics:
@@ -215,6 +217,8 @@ def disable(cls, join=True):
 
         log.debug("Disabling %s", cls.__name__)
 
+        remoteconfig_poller.unregister("LIVE_DEBUGGING")
+
         forksafe.unregister(cls._restart)
         atexit.unregister(cls.disable)
         unregister_post_run_module_hook(cls._on_run_module)
@@ -229,6 +233,8 @@ def disable(cls, join=True):
         if di_config.metrics:
             metrics.disable()
 
+        di_config.enabled = False
+
         log.debug("%s disabled", cls.__name__)
 
     def __init__(self, tracer=None):

releasenotes/notes/fix-di-enable-programmatic-api-2dd583ac87af5451.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    dynamic instrumentation: Fixed the programmatic API to ensure that the
+    dynamic instrumentation service is fully enabled when
+    ``Dynamic Instrumentation.enable()`` is called.

tests/debugging/test_api.py

@@ -1,7 +1,5 @@
 import pytest
 
-from ddtrace.debugging import DynamicInstrumentation
-
 
 @pytest.mark.subprocess(ddtrace_run=True, env=dict(DD_DYNAMIC_INSTRUMENTATION_ENABLED="true"), err=None)
 def test_debugger_enabled_ddtrace_run():
@@ -17,12 +15,20 @@ def test_debugger_disabled_ddtrace_run():
     assert DynamicInstrumentation._instance is None
 
 
+@pytest.mark.subprocess
 def test_debugger_enabled_programmatically():
+    from ddtrace.internal.remoteconfig.worker import remoteconfig_poller
+
+    assert "LIVE_DEBUGGING" not in remoteconfig_poller._client._products
+    from ddtrace.debugging import DynamicInstrumentation
+
     DynamicInstrumentation.enable()
     assert DynamicInstrumentation._instance is not None
+    assert "LIVE_DEBUGGING" in remoteconfig_poller._client._products
 
     DynamicInstrumentation.disable()
     assert DynamicInstrumentation._instance is None
+    assert "LIVE_DEBUGGING" not in remoteconfig_poller._client._products
 
 
 @pytest.mark.subprocess(err=None)