fix: shared health check serialization (#21119)

* Add BaseModel serialization to safe_json_dumps

* Use safe_dumps in shared health check caching

* remove redundant seen.add

litellm/litellm_core_utils/safe_json_dumps.py

@@ -1,6 +1,8 @@
 import json
 from typing import Any, Union
 
+from pydantic import BaseModel
+
 from litellm.constants import DEFAULT_MAX_RECURSE_DEPTH
 
 
@@ -41,6 +43,11 @@ def safe_dumps(data: Any, max_depth: int = DEFAULT_MAX_RECURSE_DEPTH) -> str:
             result = sorted([_serialize(item, seen, depth + 1) for item in obj])
             seen.remove(id(obj))
             return result
+        elif isinstance(obj, BaseModel):
+            dumped = obj.model_dump()
+            result = _serialize(dumped, seen, depth + 1)
+            seen.remove(id(obj))
+            return result
         else:
             # Fall back to string conversion for non-serializable objects.
             try:
@@ -49,4 +56,4 @@ def safe_dumps(data: Any, max_depth: int = DEFAULT_MAX_RECURSE_DEPTH) -> str:
                 return "Unserializable Object"
 
     safe_data = _serialize(data, set(), 0)
-    return json.dumps(safe_data, default=str)
+    return json.dumps(safe_data, default=str)

litellm/proxy/health_check_utils/shared_health_check_manager.py

@@ -4,6 +4,7 @@ import time
 from typing import Any, Dict, List, Optional, Tuple
 
 from litellm._logging import verbose_proxy_logger
+from litellm.litellm_core_utils.safe_json_dumps import safe_dumps
 from litellm.caching.redis_cache import RedisCache
 from litellm.constants import (
     DEFAULT_SHARED_HEALTH_CHECK_TTL,
@@ -177,7 +178,7 @@ class SharedHealthCheckManager:
             cache_key = self.get_health_check_cache_key()
             await self.redis_cache.async_set_cache(
                 cache_key,
-                json.dumps(cache_data),
+                safe_dumps(cache_data),
                 ttl=self.health_check_ttl,
             )
             

tests/test_litellm/litellm_core_utils/test_safe_json_dumps.py

@@ -138,3 +138,35 @@ def test_non_standard_dict_keys_complex():
 
         traceback.print_exc()
         raise e
+
+
+def test_pydantic_base_model():
+    from pydantic import BaseModel
+
+    class InnerModel(BaseModel):
+        value: int
+        label: str
+
+    class OuterModel(BaseModel):
+        name: str
+        inner: InnerModel
+        tags: list
+
+    outer = OuterModel(name="test", inner=InnerModel(value=42, label="hello"), tags=["a", "b"])
+
+    # Test a pydantic model at the top level
+    result = json.loads(safe_dumps(outer))
+    assert result["name"] == "test"
+    assert result["inner"] == {"value": 42, "label": "hello"}
+    assert result["tags"] == ["a", "b"]
+
+    # Test pydantic models nested inside dicts and lists
+    data = {
+        "healthy_endpoints": [outer, InnerModel(value=1, label="one")],
+        "count": 2,
+    }
+    result = json.loads(safe_dumps(data))
+    assert result["count"] == 2
+    assert len(result["healthy_endpoints"]) == 2
+    assert result["healthy_endpoints"][0]["name"] == "test"
+    assert result["healthy_endpoints"][1] == {"value": 1, "label": "one"}