Add base_url option for OpenAI generator

README.md

@@ -46,6 +46,10 @@ df = ds.generate(n=10)
 ```python
 # OpenAI
 gen = chatan.generator("openai", "YOUR_OPENAI_API_KEY")
+# OpenAI-compatible service that does not require a key
+gen_alt = chatan.generator(
+    "openai", base_url="https://api.example.com/v1"
+)
 
 # Anthropic
 gen = chatan.generator("anthropic", "YOUR_ANTHROPIC_API_KEY")

docs/source/datasets_and_generators.rst

@@ -10,6 +10,8 @@ Supported generator providers
 Chatan includes built-in clients for a few common model sources:
 
 * ``openai`` - access GPT models via the OpenAI API
+  (use ``base_url`` for OpenAI-compatible endpoints; API key required
+  only when ``base_url`` is omitted)
 * ``anthropic`` - use Claude models from Anthropic
 * ``transformers``/``huggingface`` - run local HuggingFace models with ``transformers``
 

docs/source/quickstart.rst

@@ -18,8 +18,12 @@ Basic Usage
    .. code-block:: python
 
       import chatan
-
-      gen = chatan.generator("openai", "YOUR_OPENAI_API_KEY")
+
+   gen = chatan.generator("openai", "YOUR_OPENAI_API_KEY")
+   # use an OpenAI-compatible service that doesn't need a key
+   # gen = chatan.generator(
+   #     "openai", base_url="https://api.example.com/v1"
+   # )
       # or for Anthropic
       # gen = chatan.generator("anthropic", "YOUR_ANTHROPIC_API_KEY")
 

src/chatan/generator.py

@@ -29,8 +29,34 @@ def generate(self, prompt: str, **kwargs) -> str:
 class OpenAIGenerator(BaseGenerator):
     """OpenAI GPT generator."""
 
-    def __init__(self, api_key: str, model: str = "gpt-3.5-turbo", **kwargs):
-        self.client = openai.OpenAI(api_key=api_key)
+    def __init__(
+        self,
+        api_key: Optional[str] = None,
+        model: str = "gpt-3.5-turbo",
+        base_url: Optional[str] = None,
+        **kwargs,
+    ) -> None:
+        """Initialize the generator.
+
+        Parameters
+        ----------
+        api_key:
+            API key for authenticating with the OpenAI service. Required if
+            ``base_url`` is not provided.
+        model:
+            Model name to use for generation.
+        base_url:
+            Optional custom API base URL for OpenAI compatible services.
+        **kwargs:
+            Additional default parameters passed to ``chat.completions.create``.
+        """
+
+        client_kwargs = {}
+        if api_key is not None:
+            client_kwargs["api_key"] = api_key
+        if base_url is not None:
+            client_kwargs["base_url"] = base_url
+        self.client = openai.OpenAI(**client_kwargs)
         self.model = model
         self.default_kwargs = kwargs
 
@@ -209,7 +235,7 @@ def __init__(self, provider: str, api_key: Optional[str] = None, **kwargs):
         provider_lower = provider.lower()
         try:
             if provider_lower == "openai":
-                if api_key is None:
+                if api_key is None and kwargs.get("base_url") is None:
                     raise ValueError("API key is required for OpenAI")
                 self._generator = OpenAIGenerator(api_key, **kwargs)
             elif provider_lower == "anthropic":
@@ -256,6 +282,9 @@ def generator(
     provider: str = "openai", api_key: Optional[str] = None, **kwargs
 ) -> GeneratorClient:
     """Create a generator client."""
-    if provider.lower() in {"openai", "anthropic"} and api_key is None:
+    if provider.lower() == "openai":
+        if api_key is None and kwargs.get("base_url") is None:
+            raise ValueError("API key is required")
+    elif provider.lower() == "anthropic" and api_key is None:
         raise ValueError("API key is required")
     return GeneratorClient(provider, api_key, **kwargs)