Runnable Example: Standalone Function (No Server)
When the app is a plain Python function or module — no web framework, no server, no infrastructure.
Approach: Import and call the function directly from run(). This is the simplest case.
# pixie_qa/run_app.py
from pydantic import BaseModel
import pixie
class AppArgs(BaseModel):
question: str
class AppRunnable(pixie.Runnable[AppArgs]):
"""Drives a standalone function for tracing and evaluation."""
@classmethod
def create(cls) -> "AppRunnable":
return cls()
async def run(self, args: AppArgs) -> None:
from myapp.agent import answer_question
await answer_question(args.question)If the function is synchronous, wrap it with asyncio.to_thread:
import asyncio
async def run(self, args: AppArgs) -> None:
from myapp.agent import answer_question
await asyncio.to_thread(answer_question, args.question)If the function depends on an external service (e.g., a vector store), the wrap(purpose="input") calls you added in Step 2a handle it automatically — the registry injects test data in eval mode.
When to use setup() / teardown()
Most standalone functions don't need lifecycle methods. Use them only when the function requires a shared resource (e.g., a pre-loaded embedding model, a database connection):
class AppRunnable(pixie.Runnable[AppArgs]):
_model: SomeModel
@classmethod
def create(cls) -> "AppRunnable":
return cls()
async def setup(self) -> None:
from myapp.models import load_model
self._model = load_model()
async def run(self, args: AppArgs) -> None:
from myapp.agent import answer_question
await answer_question(args.question, model=self._model)