getsentry · lobsterkatie · Aug 25, 2021 · Aug 24, 2021 · Aug 24, 2021 · Aug 24, 2021
diff --git a/sentry_sdk/client.py b/sentry_sdk/client.py
@@ -332,7 +332,7 @@ def capture_event(
 
         # this is outside of the `if` immediately below because even if we don't
         # use the value, we want to make sure we remove it before the event is
-        # sent (which the `.pop()` does)
+        # sent
         raw_tracestate = (
             event_opt.get("contexts", {}).get("trace", {}).pop("tracestate", "")
         )

diff --git a/sentry_sdk/integrations/httpx.py b/sentry_sdk/integrations/httpx.py
@@ -1,5 +1,6 @@
 from sentry_sdk import Hub
 from sentry_sdk.integrations import Integration, DidNotEnable
+from sentry_sdk.utils import logger
 
 from sentry_sdk._types import MYPY
 
@@ -45,6 +46,11 @@ def send(self, request, **kwargs):
             span.set_data("method", request.method)
             span.set_data("url", str(request.url))
             for key, value in hub.iter_trace_propagation_headers():
+                logger.debug(
+                    "[Tracing] Adding `{key}` header {value} to outgoing request to {url}.".format(
+                        key=key, value=value, url=request.url
+                    )
+                )
                 request.headers[key] = value
             rv = real_send(self, request, **kwargs)
 
@@ -72,6 +78,11 @@ async def send(self, request, **kwargs):
             span.set_data("method", request.method)
             span.set_data("url", str(request.url))
             for key, value in hub.iter_trace_propagation_headers():
+                logger.debug(
+                    "[Tracing] Adding `{key}` header {value} to outgoing request to {url}.".format(
+                        key=key, value=value, url=request.url
+                    )
+                )
                 request.headers[key] = value
             rv = await real_send(self, request, **kwargs)
 

diff --git a/sentry_sdk/integrations/stdlib.py b/sentry_sdk/integrations/stdlib.py
@@ -7,7 +7,7 @@
 from sentry_sdk.integrations import Integration
 from sentry_sdk.scope import add_global_event_processor
 from sentry_sdk.tracing_utils import EnvironHeaders
-from sentry_sdk.utils import capture_internal_exceptions, safe_repr
+from sentry_sdk.utils import capture_internal_exceptions, logger, safe_repr
 
 from sentry_sdk._types import MYPY
 
@@ -86,6 +86,11 @@ def putrequest(self, method, url, *args, **kwargs):
         rv = real_putrequest(self, method, url, *args, **kwargs)
 
         for key, value in hub.iter_trace_propagation_headers(span):
+            logger.debug(
+                "[Tracing] Adding `{key}` header {value} to outgoing request to {real_url}.".format(
+                    key=key, value=value, real_url=real_url
+                )
+            )
             self.putheader(key, value)
 
         self._sentrysdk_span = span

diff --git a/sentry_sdk/scope.py b/sentry_sdk/scope.py
@@ -174,7 +174,7 @@ def transaction(self, value):
         # anything set in the scope.
         # XXX: note that with the introduction of the Scope.transaction getter,
         # there is a semantic and type mismatch between getter and setter. The
-        # getter returns a transaction, the setter sets a transaction name.
+        # getter returns a Transaction, the setter sets a transaction name.
         # Without breaking version compatibility, we could make the setter set a
         # transaction name or transaction (self._span) depending on the type of
         # the value argument.

diff --git a/sentry_sdk/tracing.py b/sentry_sdk/tracing.py
@@ -22,12 +22,12 @@
 if MYPY:
     import typing
 
-    from typing import Generator
     from typing import Optional
     from typing import Any
     from typing import Dict
     from typing import List
     from typing import Tuple
+    from typing import Iterator
 
     from sentry_sdk._types import SamplingContext
 
@@ -183,19 +183,19 @@ def start_child(self, **kwargs):
         """
         kwargs.setdefault("sampled", self.sampled)
 
-        rv = Span(
+        child = Span(
             trace_id=self.trace_id, span_id=None, parent_span_id=self.span_id, **kwargs
         )
 
         if isinstance(self, Transaction):
-            rv._containing_transaction = self
+            child._containing_transaction = self
         else:
-            rv._containing_transaction = self._containing_transaction
+            child._containing_transaction = self._containing_transaction
 
-        rv._span_recorder = recorder = self._span_recorder
+        child._span_recorder = recorder = self._span_recorder
         if recorder:
-            recorder.add(rv)
-        return rv
+            recorder.add(child)
+        return child
 
     def new_span(self, **kwargs):
         # type: (**Any) -> Span
@@ -253,9 +253,15 @@ def continue_from_headers(
         return transaction
 
     def iter_headers(self):
-        # type: () -> Generator[Tuple[str, str], None, None]
+        # type: () -> Iterator[Tuple[str, str]]
+        """
+        Creates a generator which returns the span's `sentry-trace` and
+        `tracestate` headers.
+        """
         yield "sentry-trace", self.to_traceparent()
+
         tracestate = self.to_tracestate()
+        # `tracestate` will only be `None` if there's no client or no DSN
         if tracestate:
             yield "tracestate", tracestate
 
@@ -295,9 +301,11 @@ def to_traceparent(self):
     def to_tracestate(self):
         # type: () -> Optional[str]
         """
-        Generates the `tracestate` header value to attach to outgoing requests.
+        Computes the `tracestate` header value using data from the containing
+        transaction.
+
+        Returns None if there's no client and/or no DSN.
         """
        header_value = None
 
         if isinstance(self, Transaction):
             transaction = self  # type: Optional[Transaction]

diff --git a/sentry_sdk/tracing_utils.py b/sentry_sdk/tracing_utils.py
@@ -285,6 +285,9 @@ def compute_tracestate_value(data):
     # type: (typing.Mapping[str, str]) -> str
     """
     Computes a new tracestate value using the given data.
+
+    Note: Returns just the base64-encoded data, NOT the full `sentry=...`
+    tracestate entry.
     """
 
     tracestate_json = json.dumps(data)
@@ -300,7 +303,9 @@ def compute_tracestate_value(data):
 def compute_tracestate_entry(span):
     # type: (Span) -> str
     """
-    Computes a new tracestate value for the span.
+    Computes a new sentry tracestate for the span. Includes the `sentry=`.
+
+    Will return `None` if there's no client and/or no DSN.
     """
     data = {}