Add local model provider boundary

SovereignAI-Starter/app/model_provider.py

@@ -0,0 +1,139 @@
+"""Provider boundary for local and future model backends."""
+
+from __future__ import annotations
+
+import json
+import os
+from collections.abc import AsyncIterator
+from typing import Any, Protocol
+
+import httpx
+from fastapi import HTTPException
+
+
+class ModelProvider(Protocol):
+    name: str
+    default_model: str
+    base_url: str
+
+    def prepare_payload(self, payload: dict[str, Any]) -> dict[str, Any]: ...
+
+    async def complete(
+        self, payload: dict[str, Any], *, timeout_seconds: float = 180.0
+    ) -> dict[str, Any]: ...
+
+    async def stream(
+        self, payload: dict[str, Any]
+    ) -> AsyncIterator[dict[str, Any]]: ...
+
+    async def list_models(self) -> list[str]: ...
+
+
+class OllamaProvider:
+    name = "ollama"
+
+    def __init__(self, base_url: str, default_model: str) -> None:
+        self.base_url = base_url.rstrip("/")
+        self.default_model = default_model
+
+    def prepare_payload(self, payload: dict[str, Any]) -> dict[str, Any]:
+        prepared = dict(payload)
+        model = str(prepared.get("model", self.default_model))
+        prepared.setdefault("model", model)
+        # Gemma 4 via Ollama otherwise returns its reasoning in a separate field.
+        if model.lower().startswith("gemma4"):
+            prepared.setdefault("reasoning_effort", "none")
+        return prepared
+
+    async def complete(
+        self, payload: dict[str, Any], *, timeout_seconds: float = 180.0
+    ) -> dict[str, Any]:
+        try:
+            async with httpx.AsyncClient(timeout=timeout_seconds) as client:
+                response = await client.post(
+                    f"{self.base_url}/chat/completions",
+                    json=self.prepare_payload(payload),
+                )
+                response.raise_for_status()
+                return response.json()
+        except httpx.HTTPStatusError as exc:
+            detail = exc.response.text[:400] or "رفض خادم النموذج الطلب."
+            raise HTTPException(
+                status_code=502,
+                detail=f"خطأ من خادم النموذج المحلي: {detail}",
+            ) from exc
+        except httpx.RequestError as exc:
+            raise HTTPException(
+                status_code=503,
+                detail="تعذر الاتصال بـ Ollama المحلي على العنوان المضبوط.",
+            ) from exc
+        except ValueError as exc:
+            raise HTTPException(
+                status_code=502, detail="أعاد Ollama استجابة JSON غير صالحة."
+            ) from exc
+
+    async def stream(
+        self, payload: dict[str, Any]
+    ) -> AsyncIterator[dict[str, Any]]:
+        try:
+            timeout = httpx.Timeout(connect=15.0, read=None, write=30.0, pool=30.0)
+            async with httpx.AsyncClient(timeout=timeout) as client:
+                async with client.stream(
+                    "POST",
+                    f"{self.base_url}/chat/completions",
+                    json=self.prepare_payload(payload),
+                ) as response:
+                    if response.status_code >= 400:
+                        detail = (await response.aread()).decode("utf-8", "replace")[:400]
+                        yield {"error": f"Ollama {response.status_code}: {detail}"}
+                        return
+                    async for line in response.aiter_lines():
+                        if not line.startswith("data:"):
+                            continue
+                        raw = line[5:].strip()
+                        if raw == "[DONE]":
+                            yield {"done": True}
+                            return
+                        try:
+                            event = json.loads(raw)
+                            delta = event["choices"][0].get("delta", {}).get("content")
+                        except (ValueError, KeyError, IndexError, TypeError):
+                            continue
+                        if delta:
+                            yield {"delta": delta}
+                    yield {"done": True}
+        except httpx.RequestError:
+            yield {"error": "تعذر الاتصال بـ Ollama المحلي."}
+
+    async def list_models(self) -> list[str]:
+        ollama_base = (
+            self.base_url[:-3] if self.base_url.endswith("/v1") else self.base_url
+        )
+        try:
+            async with httpx.AsyncClient(timeout=10.0) as client:
+                response = await client.get(f"{ollama_base}/api/tags")
+                response.raise_for_status()
+                payload = response.json()
+        except (httpx.HTTPError, ValueError) as exc:
+            raise HTTPException(
+                status_code=503,
+                detail="تعذر جلب قائمة النماذج من Ollama المحلي.",
+            ) from exc
+        return [
+            item["name"]
+            for item in payload.get("models", [])
+            if isinstance(item, dict) and item.get("name")
+        ]
+
+
+def get_model_provider() -> ModelProvider:
+    provider_name = os.getenv("MODEL_PROVIDER", "ollama").strip().lower()
+    if provider_name != "ollama":
+        raise HTTPException(
+            status_code=503,
+            detail=f"مزوّد النموذج '{provider_name}' غير مدعوم حاليًا.",
+        )
+    return OllamaProvider(
+        base_url=os.getenv("LOCAL_LLM_BASE_URL", "http://127.0.0.1:11434/v1"),
+        default_model=os.getenv("LOCAL_MODEL", "gemma4:e2b"),
+    )