fix(mavvrik): lazy import Service in mavvrik_endpoints to avoid polars at startup

Importing 'from litellm.integrations.mavvrik import Service' at module level
caused the entire mavvrik package to load at proxy startup, which could
transitively import polars (optional [proxy] dep) for SDK-only users.

Fix: lazy import via _get_service() helper — Service (and the polars dep chain)
is only loaded when a Mavvrik endpoint is actually called, not at import time.

Note: cloudzero_endpoints.py and vantage_endpoints.py use the same
unconditional pattern; we've proactively fixed ours to be stricter.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

litellm/proxy/spend_tracking/mavvrik_endpoints.py

@@ -17,7 +17,6 @@ from typing import AsyncIterator
 
 from fastapi import APIRouter, Depends, HTTPException
 
-from litellm.integrations.mavvrik import Service
 from litellm.proxy._types import CommonProxyErrors, LitellmUserRoles, UserAPIKeyAuth
 from litellm.proxy.auth.user_api_key_auth import user_api_key_auth
 from litellm.types.proxy.mavvrik_endpoints import (
@@ -33,6 +32,14 @@ from litellm.types.proxy.mavvrik_endpoints import (
 
 router = APIRouter()
 
+
+def _get_service():
+    """Lazy import of Service — keeps polars (optional [proxy] dep) out of startup."""
+    from litellm.integrations.mavvrik import Service  # noqa: PLC0415
+
+    return Service()
+
+
 # ---------------------------------------------------------------------------
 # Shared helpers
 # ---------------------------------------------------------------------------
@@ -88,7 +95,7 @@ async def init_mavvrik_settings(
     """Initialize Mavvrik settings and register the background export job."""
     _require_admin(user_api_key_dict)
     async with _mavvrik_errors():
-        result = await Service().initialize(
+        result = await _get_service().initialize(
             api_key=request.api_key,
             api_endpoint=request.api_endpoint,
             connection_id=request.connection_id,
@@ -113,7 +120,7 @@ async def get_mavvrik_settings(
     """View current Mavvrik settings. The API key is masked in the response."""
     _require_admin(user_api_key_dict)
     async with _mavvrik_errors():
-        result = await Service().get_settings()
+        result = await _get_service().get_settings()
         return MavvrikSettingsView(**result)
 
 
@@ -145,7 +152,7 @@ async def update_mavvrik_settings(
         )
 
     async with _mavvrik_errors():
-        result = await Service().update_settings(
+        result = await _get_service().update_settings(
             api_key=request.api_key,
             api_endpoint=request.api_endpoint,
             connection_id=request.connection_id,
@@ -170,7 +177,7 @@ async def delete_mavvrik_settings(
     """Remove all Mavvrik settings and deregister the background job."""
     _require_admin(user_api_key_dict)
     async with _mavvrik_errors():
-        result = await Service().delete()
+        result = await _get_service().delete()
         return MavvrikDeleteResponse(**result)
 
 
@@ -192,7 +199,7 @@ async def dry_run_mavvrik_export(
     """Preview the CSV records that would be uploaded for a given date without sending data."""
     _require_admin(user_api_key_dict)
     async with _mavvrik_errors():
-        result = await Service().dry_run(
+        result = await _get_service().dry_run(
             date_str=request.date_str,
             limit=request.limit,
         )
@@ -217,7 +224,7 @@ async def export_mavvrik_data(
     """Manually trigger a Mavvrik export for a specific date."""
     _require_admin(user_api_key_dict)
     async with _mavvrik_errors():
-        result = await Service().export(
+        result = await _get_service().export(
             date_str=request.date_str,
             limit=request.limit,
         )