feat(services/bsl): add llm_router — cf-text via cf-orch on cloud, LLMRouter (ollama/vllm) local fallback

refs kiwi#68

app/services/meal_plan/llm_router.py

@@ -0,0 +1,96 @@
+# app/services/meal_plan/llm_router.py
+# BSL 1.1 — LLM feature
+"""Provide a router-compatible LLM client for meal plan generation tasks.
+
+Cloud (CF_ORCH_URL set):
+  Allocates a cf-text service via cf-orch (3B-7B GGUF, ~2GB VRAM).
+  Returns an _OrchTextRouter that wraps the cf-text HTTP endpoint
+  with a .complete(system, user, **kwargs) interface.
+
+Local / self-hosted (no CF_ORCH_URL):
+  Returns an LLMRouter instance which tries ollama, vllm, or any
+  backend configured in ~/.config/circuitforge/llm.yaml.
+
+Both paths expose the same interface so llm_timing.py and llm_planner.py
+need no knowledge of the backend.
+"""
+from __future__ import annotations
+
+import logging
+import os
+from contextlib import nullcontext
+
+logger = logging.getLogger(__name__)
+
+# cf-orch service name and VRAM budget for meal plan LLM tasks.
+# These are lighter than recipe_llm (4.0 GB) — cf-text handles them.
+_SERVICE_TYPE = "cf-text"
+_TTL_S = 120.0
+_CALLER = "kiwi-meal-plan"
+
+
+class _OrchTextRouter:
+    """Thin adapter that makes a cf-text HTTP endpoint look like LLMRouter."""
+
+    def __init__(self, base_url: str) -> None:
+        self._base_url = base_url.rstrip("/")
+
+    def complete(
+        self,
+        system: str = "",
+        user: str = "",
+        max_tokens: int = 512,
+        temperature: float = 0.7,
+        **_kwargs,
+    ) -> str:
+        from openai import OpenAI
+        client = OpenAI(base_url=self._base_url + "/v1", api_key="any")
+        messages = []
+        if system:
+            messages.append({"role": "system", "content": system})
+        messages.append({"role": "user", "content": user})
+        try:
+            model = client.models.list().data[0].id
+        except Exception:
+            model = "local"
+        resp = client.chat.completions.create(
+            model=model,
+            messages=messages,
+            max_tokens=max_tokens,
+            temperature=temperature,
+        )
+        return resp.choices[0].message.content or ""
+
+
+def get_meal_plan_router():
+    """Return an LLM client for meal plan tasks.
+
+    Tries cf-orch cf-text allocation first (cloud); falls back to LLMRouter
+    (local ollama/vllm). Returns None if no backend is available.
+    """
+    cf_orch_url = os.environ.get("CF_ORCH_URL")
+    if cf_orch_url:
+        try:
+            from circuitforge_orch.client import CFOrchClient
+            client = CFOrchClient(cf_orch_url)
+            ctx = client.allocate(
+                service=_SERVICE_TYPE,
+                ttl_s=_TTL_S,
+                caller=_CALLER,
+            )
+            alloc = ctx.__enter__()
+            if alloc is not None:
+                return _OrchTextRouter(alloc.url), ctx
+        except Exception as exc:
+            logger.debug("cf-orch cf-text allocation failed, falling back to LLMRouter: %s", exc)
+
+    # Local fallback: LLMRouter (ollama / vllm / openai-compat)
+    try:
+        from circuitforge_core.llm.router import LLMRouter
+        return LLMRouter(), nullcontext(None)
+    except FileNotFoundError:
+        logger.debug("LLMRouter: no llm.yaml and no LLM env vars — meal plan LLM disabled")
+        return None, nullcontext(None)
+    except Exception as exc:
+        logger.debug("LLMRouter init failed: %s", exc)
+        return None, nullcontext(None)