Files
DECNET/decnet/realism/llm/factory.py

61 lines
2.4 KiB
Python

"""Backend dispatch.
Reads ``DECNET_REALISM_LLM`` to pick a concrete :class:`LLMBackend`.
Defaults to ``ollama`` because that's what the prototype proved out and
what most dev boxes have on hand.
Supported keys:
* ``ollama`` — :class:`decnet.realism.llm.impl.ollama.OllamaBackend`
* ``fake`` — :class:`decnet.realism.llm.impl.fake.FakeBackend`
(canned output, used by tests so they don't shell out)
Anthropic / vLLM / llama.cpp slots in here as a third branch when the
need shows up. Per the provider-subpackages convention, do NOT collapse
factory dispatch into the impl modules — keeps the ``__init__`` import
graph cycle-free and the env contract auditable in one place.
"""
from __future__ import annotations
import os
from typing import Any
from decnet.realism.llm.base import LLMBackend
def get_llm(*, model: str | None = None, **kwargs: Any) -> LLMBackend:
"""Instantiate the LLM backend selected by DB config or environment.
Resolution order:
1. Process-level cached backend (populated by the DB config row via
:func:`decnet.realism.llm.config.apply`). Returned as-is when
*model* and *kwargs* are both absent — the common case.
2. Env-var path (``DECNET_REALISM_LLM`` / ``DECNET_REALISM_MODEL`` /
``DECNET_REALISM_TIMEOUT``) — legacy / default-install fallback.
*model* (when provided) overrides whatever the backend's own default
is — e.g. for :class:`OllamaBackend` that's ``llama3.1`` unless
``DECNET_REALISM_MODEL`` says otherwise. Lets the worker honour
``decnet orchestrate --model gpt-oss`` without each backend having
to know about CLI flags.
"""
# Fast path: DB-configured cached backend.
if model is None and not kwargs:
from decnet.realism.llm.config import get_cached_backend
cached = get_cached_backend()
if cached is not None:
return cached
backend_key = os.environ.get("DECNET_REALISM_LLM", "ollama").lower()
if backend_key == "ollama":
from decnet.realism.llm.impl.ollama import OllamaBackend
return OllamaBackend(model=model, **kwargs)
if backend_key == "fake":
from decnet.realism.llm.impl.fake import FakeBackend
return FakeBackend(model=model or "fake-model", **kwargs)
raise ValueError(
f"Unsupported DECNET_REALISM_LLM={backend_key!r}; "
"expected one of: ollama, fake"
)