fix(proxy_server.py): accept keys with none duration

docs/my-website/docs/proxy/virtual_keys.md

@@ -3,6 +3,13 @@ Track Spend, Set budgets and create virtual keys for the proxy
 
 Grant other's temporary access to your proxy, with keys that expire after a set duration.
 
+
+:::info
+
+Complete API documentation in the Swagger docs on your proxy base url (e.g. `http://0.0.0.0:8000)`
+
+:::
+
 ## Quick Start
 
 Requirements: 
@@ -59,6 +66,17 @@ Expected response:
 }
 ```
 
+## Keys that don't expire
+
+Just set duration to None. 
+
+```bash
+curl --location 'http://0.0.0.0:8000/key/generate' \
+--header 'Authorization: Bearer sk-1234' \
+--header 'Content-Type: application/json' \
+--data '{"models": ["azure-models"], "aliases": {"mistral-7b": "gpt-3.5-turbo"}, "duration": null}'
+```
+
 ## Upgrade/Downgrade Models 
 
 If a user is expected to use a given model (i.e. gpt3-5), and you want to:

litellm/proxy/_types.py

@@ -149,7 +149,7 @@ class UserAPIKeyAuth(LiteLLMBase): # the expected response object for user api k
 
 class GenerateKeyResponse(LiteLLMBase):
     key: str
-    expires: datetime
+    expires: Optional[datetime]
     user_id: str
 
 class _DeleteKeyObject(LiteLLMBase):

litellm/proxy/utils.py

@@ -189,6 +189,7 @@ class PrismaClient:
                         else:
                             # Token exists but is expired.
                             raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="expired user key")
+                    return response
                 else:
                     # Token does not exist.
                     raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="invalid user key")