Files
SkillOpt/skillopt/model/openai_compatible_backend.py
2026-07-14 09:21:11 +08:00

448 lines
15 KiB
Python

"""Generic OpenAI-compatible chat backend for optimizer and target paths.
This backend talks to *any* service that exposes an OpenAI-compatible
``/chat/completions`` endpoint through the official ``openai`` SDK. A single
implementation therefore covers a large family of providers, for example:
* DeepSeek (``https://api.deepseek.com``)
* Groq (``https://api.groq.com/openai/v1``)
* Together AI (``https://api.together.xyz/v1``)
* Mistral / Fireworks / OpenRouter / Perplexity / xAI Grok
* Ollama (``http://localhost:11434/v1``)
* vLLM / SGLang / TGI self-hosted servers
* LiteLLM proxy (``http://localhost:4000``)
* Azure OpenAI and OpenAI itself
Unlike the Azure backend it never assumes Azure-specific auth or the Responses
API — it only needs a ``base_url`` and an ``api_key`` (some local servers accept
any key, so the key is optional and falls back to a harmless placeholder).
The module mirrors the callable surface of the other chat backends
(:mod:`skillopt.model.qwen_backend`, :mod:`skillopt.model.minimax_backend`) so
it can be selected as the optimizer and/or target backend and routed through
:mod:`skillopt.model`.
"""
from __future__ import annotations
import os
import threading
import time
from dataclasses import dataclass
from typing import Any
from openai import OpenAI
from skillopt.model.common import (
TokenTracker,
compat_message_from_chat_message,
default_model_for_backend,
usage_from_openai_usage,
)
BACKEND_NAME = "openai_compatible"
# A neutral, widely-available default. Real deployments should set the model
# explicitly (e.g. "deepseek-chat", "llama-3.3-70b-versatile", "qwen2.5:7b").
_DEFAULT_BASE_URL = "https://api.openai.com/v1"
@dataclass
class OpenAICompatibleConfig:
base_url: str
api_key: str
deployment: str
timeout_seconds: float
max_tokens: int
temperature: float | None
def _parse_optional_float(value: Any) -> float | None:
if value is None:
return None
raw = str(value).strip()
return float(raw) if raw else None
def _parse_int(value: Any, default: int) -> int:
if value is None:
return default
raw = str(value).strip()
return int(raw) if raw else default
def _role_env(role: str, key: str, default: str) -> str:
"""Resolve a config value, preferring role-specific over shared env vars."""
role_key = f"{role.upper()}_OPENAI_COMPATIBLE_{key}"
generic_key = f"OPENAI_COMPATIBLE_{key}"
return os.environ.get(role_key) or os.environ.get(generic_key) or default
def _initial_config(role: str) -> OpenAICompatibleConfig:
role_upper = role.upper()
deployment_env = "OPTIMIZER_DEPLOYMENT" if role == "optimizer" else "TARGET_DEPLOYMENT"
return OpenAICompatibleConfig(
base_url=_role_env(role, "BASE_URL", _DEFAULT_BASE_URL),
api_key=_role_env(role, "API_KEY", ""),
deployment=(
os.environ.get(f"{role_upper}_OPENAI_COMPATIBLE_MODEL")
or os.environ.get("OPENAI_COMPATIBLE_MODEL")
or os.environ.get(deployment_env)
or default_model_for_backend(BACKEND_NAME)
),
timeout_seconds=float(_role_env(role, "TIMEOUT_SECONDS", "300") or 300),
max_tokens=_parse_int(_role_env(role, "MAX_TOKENS", "8000"), 8000),
temperature=_parse_optional_float(_role_env(role, "TEMPERATURE", "")),
)
OPTIMIZER_CONFIG = _initial_config("optimizer")
TARGET_CONFIG = _initial_config("target")
_config_lock = threading.Lock()
_client_lock = threading.Lock()
tracker = TokenTracker()
_optimizer_client: OpenAI | None = None
_target_client: OpenAI | None = None
def _config_for(role: str) -> OpenAICompatibleConfig:
return OPTIMIZER_CONFIG if role == "optimizer" else TARGET_CONFIG
def _build_client(config: OpenAICompatibleConfig) -> OpenAI:
return OpenAI(
base_url=config.base_url.rstrip("/") or _DEFAULT_BASE_URL,
# Some OpenAI-compatible servers (Ollama, vLLM, local proxies) do not
# require an API key. The SDK still expects a non-empty string, so fall
# back to a harmless placeholder when none is configured.
api_key=config.api_key or "dummy",
timeout=config.timeout_seconds,
)
def _get_client(role: str) -> OpenAI:
global _optimizer_client, _target_client
with _client_lock:
if role == "optimizer":
if _optimizer_client is None:
_optimizer_client = _build_client(OPTIMIZER_CONFIG)
return _optimizer_client
if _target_client is None:
_target_client = _build_client(TARGET_CONFIG)
return _target_client
def _reset_clients() -> None:
global _optimizer_client, _target_client
with _client_lock:
_optimizer_client = None
_target_client = None
def count_tokens(text: str, model: str | None = None) -> int:
"""Best-effort token count for a string.
Uses ``tiktoken`` when available (per-model encoding, falling back to the
``cl100k_base`` encoding). If ``tiktoken`` is not installed or fails — which
is common for non-OpenAI models served through compatible APIs — it falls
back to a character-based estimate of roughly four characters per token.
"""
if not text:
return 0
try:
import tiktoken
try:
encoding = tiktoken.encoding_for_model(model or "gpt-4o")
except Exception: # noqa: BLE001 - unknown/non-OpenAI model name
encoding = tiktoken.get_encoding("cl100k_base")
return len(encoding.encode(text))
except Exception: # noqa: BLE001 - tiktoken missing or encoding failure
# Rough heuristic: ~4 characters per token for English-like text.
return max(1, (len(text) + 3) // 4)
def _chat_messages_impl(
messages: list[dict[str, Any]],
max_completion_tokens: int,
retries: int,
stage: str,
*,
role: str,
tools: list[dict[str, Any]] | None = None,
tool_choice: str | dict[str, Any] | None = None,
return_message: bool = False,
deployment: str | None = None,
timeout: float | None = None,
) -> tuple[Any, dict[str, int]]:
config = _config_for(role)
client = _get_client(role)
kwargs: dict[str, Any] = {
"model": deployment or config.deployment,
"messages": messages,
# ``max_tokens`` (rather than ``max_completion_tokens``) is the field
# understood by the broadest set of OpenAI-compatible providers.
"max_tokens": min(max_completion_tokens, config.max_tokens),
}
if config.temperature is not None:
kwargs["temperature"] = config.temperature
if tools:
kwargs["tools"] = tools
if tool_choice is not None:
kwargs["tool_choice"] = tool_choice
if timeout is not None:
kwargs["timeout"] = timeout
last_err: Exception | None = None
for attempt in range(retries):
try:
resp = client.chat.completions.create(**kwargs)
choices = getattr(resp, "choices", None) or []
if not choices:
raise RuntimeError(
f"OpenAI-compatible API returned no choices: {resp!r}"
)
message = choices[0].message
text = message.content or ""
usage_info = usage_from_openai_usage(getattr(resp, "usage", None))
tracker.record(
stage,
usage_info["prompt_tokens"],
usage_info["completion_tokens"],
)
if return_message:
return compat_message_from_chat_message(message), usage_info
return text, usage_info
except Exception as e: # noqa: BLE001
last_err = e
time.sleep(min(2 ** attempt, 30))
raise RuntimeError(
f"OpenAI-compatible chat call failed after {retries} retries: {last_err}"
)
# ── Public API (mirrors the other chat backends) ─────────────────────────────
def chat_optimizer(
system: str,
user: str,
max_completion_tokens: int = 16384,
retries: int = 5,
stage: str = "optimizer",
reasoning_effort: str | None = None,
timeout: float | None = None,
) -> tuple[str, dict[str, int]]:
del reasoning_effort # not forwarded — kept for a uniform signature
messages = [
{"role": "system", "content": system},
{"role": "user", "content": user},
]
return _chat_messages_impl(
messages,
max_completion_tokens,
retries,
stage,
role="optimizer",
timeout=timeout,
)
def chat_target(
system: str,
user: str,
max_completion_tokens: int = 16384,
retries: int = 5,
stage: str = "target",
reasoning_effort: str | None = None,
timeout: float | None = None,
) -> tuple[str, dict[str, int]]:
del reasoning_effort
messages = [
{"role": "system", "content": system},
{"role": "user", "content": user},
]
return _chat_messages_impl(
messages,
max_completion_tokens,
retries,
stage,
role="target",
timeout=timeout,
)
def chat_optimizer_messages(
messages: list[dict[str, Any]],
max_completion_tokens: int = 16384,
retries: int = 5,
stage: str = "optimizer",
reasoning_effort: str | None = None,
*,
tools: list[dict[str, Any]] | None = None,
tool_choice: str | dict[str, Any] | None = None,
return_message: bool = False,
timeout: float | None = None,
) -> tuple[Any, dict[str, int]]:
del reasoning_effort
return _chat_messages_impl(
messages,
max_completion_tokens,
retries,
stage,
role="optimizer",
tools=tools,
tool_choice=tool_choice,
return_message=return_message,
timeout=timeout,
)
def chat_target_messages(
messages: list[dict[str, Any]],
max_completion_tokens: int = 16384,
retries: int = 5,
stage: str = "target",
reasoning_effort: str | None = None,
*,
tools: list[dict[str, Any]] | None = None,
tool_choice: str | dict[str, Any] | None = None,
return_message: bool = False,
timeout: float | None = None,
) -> tuple[Any, dict[str, int]]:
del reasoning_effort
return _chat_messages_impl(
messages,
max_completion_tokens,
retries,
stage,
role="target",
tools=tools,
tool_choice=tool_choice,
return_message=return_message,
timeout=timeout,
)
# ── Configuration / lifecycle ────────────────────────────────────────────────
def _update_config(
config: OpenAICompatibleConfig,
role: str,
*,
base_url: str | None = None,
api_key: str | None = None,
deployment: str | None = None,
temperature: float | str | None = None,
timeout_seconds: float | str | None = None,
max_tokens: int | str | None = None,
) -> None:
env_prefix = role.upper()
if base_url is not None:
config.base_url = str(base_url).strip() or config.base_url
os.environ[f"{env_prefix}_OPENAI_COMPATIBLE_BASE_URL"] = config.base_url
if api_key is not None:
config.api_key = str(api_key).strip()
os.environ[f"{env_prefix}_OPENAI_COMPATIBLE_API_KEY"] = config.api_key
if deployment is not None:
config.deployment = str(deployment).strip() or config.deployment
os.environ[f"{env_prefix}_OPENAI_COMPATIBLE_MODEL"] = config.deployment
if temperature is not None:
raw = str(temperature).strip()
config.temperature = float(raw) if raw else None
os.environ[f"{env_prefix}_OPENAI_COMPATIBLE_TEMPERATURE"] = raw
if timeout_seconds is not None:
config.timeout_seconds = float(timeout_seconds)
os.environ[f"{env_prefix}_OPENAI_COMPATIBLE_TIMEOUT_SECONDS"] = str(timeout_seconds)
if max_tokens is not None:
config.max_tokens = int(max_tokens)
os.environ[f"{env_prefix}_OPENAI_COMPATIBLE_MAX_TOKENS"] = str(max_tokens)
def configure_openai_compatible(
*,
base_url: str | None = None,
api_key: str | None = None,
model: str | None = None,
temperature: float | str | None = None,
timeout_seconds: float | str | None = None,
max_tokens: int | str | None = None,
optimizer_base_url: str | None = None,
optimizer_api_key: str | None = None,
optimizer_model: str | None = None,
target_base_url: str | None = None,
target_api_key: str | None = None,
target_model: str | None = None,
) -> None:
"""Configure the generic OpenAI-compatible backend at runtime.
Shared values apply to both the optimizer and target roles; the
``optimizer_*`` / ``target_*`` variants override them per role.
"""
with _config_lock:
if base_url is not None:
os.environ["OPENAI_COMPATIBLE_BASE_URL"] = str(base_url).strip()
if api_key is not None:
os.environ["OPENAI_COMPATIBLE_API_KEY"] = str(api_key).strip()
if model is not None:
os.environ["OPENAI_COMPATIBLE_MODEL"] = str(model).strip()
if temperature is not None:
os.environ["OPENAI_COMPATIBLE_TEMPERATURE"] = str(temperature).strip()
if timeout_seconds is not None:
os.environ["OPENAI_COMPATIBLE_TIMEOUT_SECONDS"] = str(timeout_seconds)
if max_tokens is not None:
os.environ["OPENAI_COMPATIBLE_MAX_TOKENS"] = str(max_tokens)
_update_config(
OPTIMIZER_CONFIG,
"optimizer",
base_url=optimizer_base_url if optimizer_base_url is not None else base_url,
api_key=optimizer_api_key if optimizer_api_key is not None else api_key,
deployment=optimizer_model if optimizer_model is not None else model,
temperature=temperature,
timeout_seconds=timeout_seconds,
max_tokens=max_tokens,
)
_update_config(
TARGET_CONFIG,
"target",
base_url=target_base_url if target_base_url is not None else base_url,
api_key=target_api_key if target_api_key is not None else api_key,
deployment=target_model if target_model is not None else model,
temperature=temperature,
timeout_seconds=timeout_seconds,
max_tokens=max_tokens,
)
_reset_clients()
def get_max_tokens() -> int:
return TARGET_CONFIG.max_tokens
def get_token_summary() -> dict[str, dict[str, int]]:
return tracker.summary()
def reset_token_tracker() -> None:
tracker.reset()
def set_reasoning_effort(effort: str | None) -> None:
# Reasoning effort is provider-specific and not universally supported by
# OpenAI-compatible endpoints, so it is intentionally a no-op here.
del effort
def set_target_deployment(deployment: str) -> None:
TARGET_CONFIG.deployment = deployment or default_model_for_backend(BACKEND_NAME)
os.environ["TARGET_DEPLOYMENT"] = TARGET_CONFIG.deployment
_reset_clients()
def set_optimizer_deployment(deployment: str) -> None:
OPTIMIZER_CONFIG.deployment = deployment or default_model_for_backend(BACKEND_NAME)
os.environ["OPTIMIZER_DEPLOYMENT"] = OPTIMIZER_CONFIG.deployment
_reset_clients()