chore: introduce APM_TRACING RC product

We introduce the APM_TRACING remote configuration product that allows
dispatching remote configuration to the library for remote enablement/
configuration of library components and features.

Author: P403n1x87

ddtrace/debugging/_debugger.py

@@ -274,8 +274,6 @@ def enable(cls) -> None:
 
         di_config.enabled = True
 
-        cls.__watchdog__.install()
-
         if di_config.metrics:
             metrics.enable()
 
@@ -307,7 +305,6 @@ def disable(cls, join: bool = True) -> None:
         cls._instance.stop(join=join)
         cls._instance = None
 
-        cls.__watchdog__.uninstall()
         if di_config.metrics:
             metrics.disable()
 

ddtrace/debugging/_products/dynamic_instrumentation.py

@@ -1,11 +1,17 @@
+from ddtrace.internal.core.event_hub import on
 from ddtrace.settings.dynamic_instrumentation import config
 
 
 requires = ["remote-configuration"]
 
 
 def post_preload():
-    pass
+    from ddtrace.debugging._debugger import Debugger
+
+    # We need to install this on start-up because if DI gets enabled remotely
+    # we won't be able to capture many of the code objects from the modules
+    # that are already loaded.
+    Debugger.__watchdog__.install()
 
 
 def start():
@@ -29,3 +35,15 @@ def stop(join=False):
 
 def at_exit(join=False):
     stop(join=join)
+
+
+def apm_tracing_rc(config):
+    enabled = config.get("dynamic_instrumentation_enabled")
+    if enabled is not None:  # and config.spec.enabled.full_name not in config.source:
+        if (config.spec.enabled.full_name not in config.source or config.enabled) and enabled:
+            start()
+        else:
+            stop()
+
+
+on("apm-tracing.rc", apm_tracing_rc, "dynamic-instrumentation")

ddtrace/internal/remoteconfig/products/__init__.py

@@ -0,0 +1,31 @@
+from ddtrace import config
+
+
+requires = ["remote-configuration"]
+
+
+def post_preload():
+    pass
+
+
+def start():
+    if config._remote_config_enabled:
+        from ddtrace.internal.remoteconfig.worker import remoteconfig_poller
+        from ddtrace.settings.remoteconfig import APMTracingAdapter
+
+        remoteconfig_poller.register("APM_TRACING", APMTracingAdapter())
+
+
+def restart(join=False):
+    pass
+
+
+def stop(join=False):
+    if config._remote_config_enabled:
+        from ddtrace.internal.remoteconfig.worker import remoteconfig_poller
+
+        remoteconfig_poller.unregister("APM_TRACING")
+
+
+def at_exit(join=False):
+    stop(join=join)

ddtrace/internal/remoteconfig/products/apm_tracing.py

@@ -0,0 +1,40 @@
+from ddtrace import config
+from ddtrace.internal.core.event_hub import dispatch
+from ddtrace.internal.logger import get_logger
+from ddtrace.internal.remoteconfig._connectors import PublisherSubscriberConnector
+from ddtrace.internal.remoteconfig._publishers import RemoteConfigPublisher
+from ddtrace.internal.remoteconfig._pubsub import PubSub
+from ddtrace.internal.remoteconfig._subscribers import RemoteConfigSubscriber
+
+
+log = get_logger(__name__)
+
+
+def _rc_callback(data, test_tracer=None):
+    for metadata, data in zip(data["metadata"], data["config"]):
+        if metadata is None or not isinstance(data, dict):
+            continue
+
+        service_target = data.get("service_target")
+        if service_target is not None:
+            service = service_target.get("service")
+            if service is not None and service != config.service:
+                continue
+
+            env = service_target.get("env")
+            if env is not None and env != config.env:
+                continue
+
+        lib_config = data.get("lib_config")
+        if lib_config is not None:
+            dispatch("apm-tracing.rc", (lib_config,))
+
+
+class APMTracingAdapter(PubSub):
+    __publisher_class__ = RemoteConfigPublisher
+    __subscriber_class__ = RemoteConfigSubscriber
+    __shared_data__ = PublisherSubscriberConnector()
+
+    def __init__(self):
+        self._publisher = self.__publisher_class__(self.__shared_data__)
+        self._subscriber = self.__subscriber_class__(self.__shared_data__, _rc_callback, "APM_TRACING")

ddtrace/internal/remoteconfig/product.py renamed to ddtrace/internal/remoteconfig/products/client.py

@@ -60,10 +60,11 @@ ddtrace = "ddtrace.contrib.pytest.plugin"
 "ddtrace.pytest_benchmark" = "ddtrace.contrib.pytest_benchmark.plugin"
 
 [project.entry-points.'ddtrace.products']
+"apm-tracing-rc" = "ddtrace.internal.remoteconfig.products.apm_tracing"
 "code-origin-for-spans" = "ddtrace.debugging._products.code_origin.span"
 "dynamic-instrumentation" = "ddtrace.debugging._products.dynamic_instrumentation"
 "exception-replay" = "ddtrace.debugging._products.exception_replay"
-"remote-configuration" = "ddtrace.internal.remoteconfig.product"
+"remote-configuration" = "ddtrace.internal.remoteconfig.products.client"
 "symbol-database" = "ddtrace.internal.symbol_db.product"
 
 [project.urls]