Source code for oumi.inference.openai_inference_engine

# Copyright 2025 - Oumi
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import copy
from typing import Any

from typing_extensions import override

from oumi.core.configs import GenerationParams, ModelParams, RemoteParams
from oumi.core.types.conversation import Conversation
from oumi.inference.remote_inference_engine import RemoteInferenceEngine

# OpenAI reasoning models that only support temperature=1.0 and don't support
# logit_bias.
# This includes o-series models and GPT-5 family.
# Reference: https://platform.openai.com/docs/guides/reasoning
_REASONING_MODEL_PREFIXES = ("o1", "o3", "o4", "gpt-5")


def _is_reasoning_model(model_name: str) -> bool:
    """Check if a model is an OpenAI reasoning model.

    Reasoning models only support temperature=1.0 and don't support logit_bias.

    Args:
        model_name: The name of the model to check.

    Returns:
        True if the model is a reasoning model, False otherwise.
    """
    return model_name.startswith(_REASONING_MODEL_PREFIXES)




class OpenAIInferenceEngine(RemoteInferenceEngine):
    """Engine for running inference against the OpenAI API."""

    @property
    @override
    def base_url(self) -> str | None:
        """Return the default base URL for the OpenAI API."""
        return "https://api.openai.com/v1/chat/completions"

    @property
    @override
    def api_key_env_varname(self) -> str | None:
        """Return the default environment variable name for the OpenAI API key."""
        return "OPENAI_API_KEY"

    @override
    def _convert_conversation_to_api_input(
        self,
        conversation: Conversation,
        generation_params: GenerationParams,
        model_params: ModelParams,
    ) -> dict[str, Any]:
        """Converts a conversation to an OpenAI input.

        Documentation: https://platform.openai.com/docs/api-reference/chat/create

        Args:
            conversation: The conversation to convert.
            generation_params: Parameters for generation during inference.
            model_params: Model parameters to use during inference.

        Returns:
            Dict[str, Any]: A dictionary representing the OpenAI input.
        """
        if _is_reasoning_model(model_params.model_name):
            generation_params = copy.deepcopy(generation_params)

            # Reasoning models do NOT support logit_bias.
            generation_params.logit_bias = {}

            # Reasoning models only support temperature = 1.0.
            generation_params.temperature = 1.0

        return super()._convert_conversation_to_api_input(
            conversation=conversation,
            generation_params=generation_params,
            model_params=model_params,
        )

    @override
    def _default_remote_params(self) -> RemoteParams:
        """Returns the default remote parameters."""
        return RemoteParams(num_workers=50, politeness_policy=60.0)