fix(spend_tracking): carry the request path in collector events that omit bodies

The collector event dropped proxy_server_request whenever spend logs do not store bodies, so the
sidecar could not tell a file or response read from a minted response and re-keyed a second read
into its own row. The event now always carries the request's method and path, and nothing else of
the request: no host, query, headers or body.

litellm/proxy/spend_tracking/spend_event.py

@@ -6,7 +6,7 @@ callback's ``kwargs`` into the projection ``_PROXY_track_cost_callback`` and
 ``DBSpendUpdateWriter.update_database`` actually read: identities and metadata, timings, usage, the
 standard logging payload without its prompt/response bodies, and the tool names. The request
 messages, the raw ``proxy_server_request`` body and the full response travel only when spend logs
-are configured to store prompts and responses. The cache key is the preset key the caching layer
+are configured to store prompts and responses; the request's method and path always travel. The cache key is the preset key the caching layer
 already computed, never a fresh hash over the request body.
 
 ``spend_event_callback_args`` rebuilds the ``(kwargs, response_obj, start_time, end_time)`` tuple
@@ -18,6 +18,7 @@ from dataclasses import dataclass
 from datetime import datetime
 from types import MappingProxyType
 from typing import Final, Literal, TypeAlias
+from urllib.parse import urlsplit
 
 from pydantic import BaseModel, ConfigDict, TypeAdapter, ValidationError
 from typing_extensions import NotRequired, ReadOnly, TypedDict
@@ -247,6 +248,19 @@ def _metadata_for_event(
     return MappingProxyType({**kept, "user_api_key_budget_reservation": budget_reservation})
 
 
+def _request_route_for_event(proxy_server_request: object) -> ObjectMapping | None:
+    """The request's method and path alone: what the spend row needs to tell a read of a stored
+    object (its id in the path) from a response minted for this call, with no host, query,
+    headers or body."""
+    request: Final = _mapping_or_none(proxy_server_request)
+    if request is None:
+        return None
+    url: Final = request.get("url")
+    if not isinstance(url, str):
+        return None
+    return MappingProxyType({"url": urlsplit(url).path, "method": request.get("method")})
+
+
 def _litellm_params_for_event(
     litellm_params: _LitellmParams, cache_key: str | None, store_bodies: bool
 ) -> _LitellmParams:
@@ -267,7 +281,11 @@ def _litellm_params_for_event(
         "user_api_key_end_user_id": litellm_params.get("user_api_key_end_user_id"),
         "metadata": _metadata_for_event(metadata, budget_reservation),
         "litellm_metadata": _metadata_for_event(litellm_metadata, budget_reservation),
-        "proxy_server_request": litellm_params.get("proxy_server_request") if store_bodies else None,
+        "proxy_server_request": (
+            litellm_params.get("proxy_server_request")
+            if store_bodies
+            else _request_route_for_event(litellm_params.get("proxy_server_request"))
+        ),
         "preset_cache_key": cache_key,
     }
     return projected

tests/test_litellm/proxy/spend_tracking/test_spend_event.py

@@ -63,7 +63,12 @@ def _success_kwargs(preset_cache_key: str | None = "preset-key") -> dict:
         "litellm_params": {
             "api_base": "https://api.openai.com",
             "preset_cache_key": preset_cache_key,
-            "proxy_server_request": {"body": {"messages": [{"role": "user", "content": _BIG_PROMPT}]}},
+            "proxy_server_request": {
+                "url": "http://litellm:4000/v1/chat/completions?api-version=2026-01-01",
+                "method": "POST",
+                "headers": {"authorization": "Bearer sk-secret"},
+                "body": {"messages": [{"role": "user", "content": _BIG_PROMPT}]},
+            },
             "metadata": {
                 "user_api_key": "hash-1",
                 "user_api_key_user_id": "user-1",
@@ -110,7 +115,9 @@ def test_event_is_compact_and_omits_bodies_by_default():
     decoded: Final = json.loads(line)
     assert "messages" not in decoded["standard_logging_object"]
     assert "response" not in decoded["standard_logging_object"]
-    assert decoded["litellm_params"]["proxy_server_request"] is None
+    assert decoded["litellm_params"]["proxy_server_request"] == {"url": "/v1/chat/completions", "method": "POST"}
+    assert b"sk-secret" not in line
+    assert b"api-version" not in line
 
 
 def test_event_carries_bodies_when_spend_logs_store_them():