OpenAI /v1/realtime api support (#6047)

* feat(azure/realtime): initial working commit for proxy azure openai realtime endpoint support

Adds support for passing /v1/realtime calls via litellm proxy

* feat(realtime_api/main.py): abstraction for handling openai realtime api calls

* feat(router.py): add `arealtime()` endpoint in router for realtime api calls

Allows using `model_list` in proxy for realtime as well

* fix: make realtime api a private function

Structure might change based on feedback. Make that clear to users.

* build(requirements.txt): add websockets to the requirements.txt

* feat(openai/realtime): add openai /v1/realtime api support

litellm/realtime_api/main.py

@@ -0,0 +1,91 @@
+"""Abstraction function for OpenAI's realtime API"""
+
+import os
+from typing import Any, Optional
+
+import litellm
+from litellm import get_llm_provider
+from litellm.secret_managers.main import get_secret_str
+from litellm.types.router import GenericLiteLLMParams
+
+from ..llms.AzureOpenAI.realtime.handler import AzureOpenAIRealtime
+from ..llms.OpenAI.realtime.handler import OpenAIRealtime
+
+azure_realtime = AzureOpenAIRealtime()
+openai_realtime = OpenAIRealtime()
+
+
+async def _arealtime(
+    model: str,
+    websocket: Any,  # fastapi websocket
+    api_base: Optional[str] = None,
+    api_key: Optional[str] = None,
+    api_version: Optional[str] = None,
+    azure_ad_token: Optional[str] = None,
+    client: Optional[Any] = None,
+    timeout: Optional[float] = None,
+    **kwargs,
+):
+    """
+    Private function to handle the realtime API call.
+
+    For PROXY use only.
+    """
+    litellm_params = GenericLiteLLMParams(**kwargs)
+
+    model, _custom_llm_provider, dynamic_api_key, dynamic_api_base = get_llm_provider(
+        model=model,
+        api_base=api_base,
+        api_key=api_key,
+    )
+
+    if _custom_llm_provider == "azure":
+        api_base = (
+            dynamic_api_base
+            or litellm_params.api_base
+            or litellm.api_base
+            or get_secret_str("AZURE_API_BASE")
+        )
+        # set API KEY
+        api_key = (
+            dynamic_api_key
+            or litellm.api_key
+            or litellm.openai_key
+            or get_secret_str("AZURE_API_KEY")
+        )
+
+        await azure_realtime.async_realtime(
+            model=model,
+            websocket=websocket,
+            api_base=api_base,
+            api_key=api_key,
+            api_version="2024-10-01-preview",
+            azure_ad_token=None,
+            client=None,
+            timeout=timeout,
+        )
+    elif _custom_llm_provider == "openai":
+        api_base = (
+            dynamic_api_base
+            or litellm_params.api_base
+            or litellm.api_base
+            or "https://api.openai.com/"
+        )
+        # set API KEY
+        api_key = (
+            dynamic_api_key
+            or litellm.api_key
+            or litellm.openai_key
+            or get_secret_str("OPENAI_API_KEY")
+        )
+
+        await openai_realtime.async_realtime(
+            model=model,
+            websocket=websocket,
+            api_base=api_base,
+            api_key=api_key,
+            client=None,
+            timeout=timeout,
+        )
+    else:
+        raise ValueError(f"Unsupported model: {model}")