feat: initial commit for starlane-router (FastAPI + Gradient)

app/main.py

@@ -0,0 +1,69 @@
+from fastapi import FastAPI, HTTPException
+from pydantic import BaseModel, Field
+from typing import Optional, Dict, Any
+import asyncio
+
+from .config import (
+    get_gradient_endpoint_url,
+    get_gradient_api_key,
+    get_gradient_auth_scheme,
+)
+from .gradient_client import call_gradient_inference
+from .router import decide_route
+
+
+app = FastAPI(title="a2a-router", version="0.1.0")
+
+
+class RouteRequest(BaseModel):
+    message: str = Field(..., description="User message to route")
+    route_hint: Optional[str] = Field(None, description="Optional explicit route: 'gradient' or 'local'")
+    metadata: Optional[Dict[str, Any]] = Field(default=None, description="Optional JSON metadata")
+
+
+class RouteResponse(BaseModel):
+    route: str
+    output: Dict[str, Any]
+
+
+@app.get("/healthz")
+async def healthz() -> Dict[str, str]:
+    return {"status": "ok"}
+
+
+@app.post("/route", response_model=RouteResponse)
+async def route_message(req: RouteRequest) -> RouteResponse:
+    route = decide_route(message=req.message, explicit_hint=req.route_hint)
+
+    if route == "local":
+        return RouteResponse(route=route, output={"echo": req.message, "metadata": req.metadata or {}})
+
+    if route == "gradient":
+        endpoint_url = get_gradient_endpoint_url()
+        api_key = get_gradient_api_key()
+        auth_scheme = get_gradient_auth_scheme()
+
+        if not endpoint_url:
+            raise HTTPException(status_code=500, detail="Missing GRADIENT_ENDPOINT_URL")
+        if not api_key:
+            raise HTTPException(status_code=500, detail="Missing GRADIENT_API_KEY")
+
+        try:
+            result = await call_gradient_inference(
+                endpoint_url=endpoint_url,
+                api_key=api_key,
+                message=req.message,
+                auth_scheme=auth_scheme,
+                extra_payload={"metadata": req.metadata} if req.metadata else None,
+            )
+            return RouteResponse(route=route, output=result)
+        except Exception as exc:
+            raise HTTPException(status_code=502, detail=f"Gradient call failed: {exc}")
+
+    raise HTTPException(status_code=400, detail=f"Unknown route: {route}")
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run("app.main:app", host="0.0.0.0", port=8080, reload=False)