chore(writer): move forksafe hooks to writer

Author: VianneyRuhlmann

ddtrace/_trace/tracer.py

@@ -203,8 +203,6 @@ def sample(self, span):
         self._sampler.sample(span)
 
     def _sample_before_fork(self) -> None:
-        if isinstance(self._span_aggregator.writer, AgentWriterInterface):
-            self._span_aggregator.writer.before_fork()
         span = self.current_root_span()
         if span is not None and span.context.sampling_priority is None:
             self.sample(span)

ddtrace/internal/writer/writer.py

@@ -14,6 +14,7 @@
 from typing import TextIO
 
 from ddtrace import config
+from ddtrace.internal import forksafe
 from ddtrace.internal.dist_computing.utils import in_ray_job
 from ddtrace.internal.hostname import get_hostname
 import ddtrace.internal.native as native
@@ -777,6 +778,8 @@ def __init__(
         self._max_payload_size = max_payload_size
         self._test_session_token = test_session_token
 
+        forksafe.register_before_fork(self.before_fork)
+
         self._clients = [client]
         self.dogstatsd = dogstatsd
         self._metrics: Dict[str, int] = defaultdict(int)
@@ -1064,6 +1067,7 @@ def _stop_service(
     ) -> None:
         # FIXME: don't join() on stop(), let the caller handle this
         super(NativeWriter, self)._stop_service()
+        forksafe.unregister_before_fork(self.before_fork)
         self.join(timeout=timeout)
 
     def before_fork(self) -> None: