Replace custom_sampling_context with attributes in ASGI

Author: sentrivana

MIGRATION_GUIDE.md

@@ -20,6 +20,7 @@ Looking to upgrade from Sentry SDK 2.x to 3.x? Here's a comprehensive list of wh
 - clickhouse-driver integration: The query is now available under the `db.query.text` span attribute (only if `send_default_pii` is `True`).
 - `sentry_sdk.init` now returns `None` instead of a context manager.
 - The `sampling_context` argument of `traces_sampler` now additionally contains all span attributes known at span start.
+- The `sampling_context` argument of `traces_sampler` doesn't contain the `asgi_scope` object anymore for ASGI frameworks. Instead, the individual properties, if available, are accessible as `asgi_scope.endpoint`, `asgi_scope.path`, `asgi_scope.root_path`, `asgi_scope.route`, `asgi_scope.scheme`, `asgi_scope.server` and `asgi_scope.type`.
 
 ### Removed
 

sentry_sdk/integrations/asgi.py

@@ -209,7 +209,7 @@ async def _run_app(self, scope, receive, send, asgi_version):
                                 name=transaction_name,
                                 source=transaction_source,
                                 origin=self.span_origin,
-                                custom_sampling_context={"asgi_scope": scope},
+                                attributes=_prepopulate_attributes(scope),
                             )
                             if should_trace
                             else nullcontext()
@@ -324,3 +324,16 @@ def _get_transaction_name_and_source(self, transaction_style, asgi_scope):
             return name, source
 
         return name, source
+
+
+def _prepopulate_attributes(scope):
+    # type: (Any) -> dict[str, Any]
+    """Unpack asgi_scope into serializable attributes."""
+    scope = scope or {}
+
+    attributes = {}
+    for attr in ("endpoint", "path", "root_path", "route", "scheme", "server", "type"):
+        if scope.get(attr):
+            attributes[f"asgi_scope.{attr}"] = scope[attr]
+
+    return attributes