antigravity-skills-reference/web-app/public/skills/dbos-python/references/lifecycle-fastapi.md

title, impact, impactDescription, tags

title	impact	impactDescription	tags
Integrate DBOS with FastAPI	CRITICAL	Proper integration ensures workflows survive server restarts	fastapi, http, server, integration

Integrate DBOS with FastAPI

When using DBOS with FastAPI, configure and launch DBOS inside the main function before starting uvicorn.

Incorrect (configuration at module level):

from fastapi import FastAPI
from dbos import DBOS, DBOSConfig

app = FastAPI()

# Don't configure at module level!
config: DBOSConfig = {"name": "my-app"}
DBOS(config=config)

@app.get("/")
@DBOS.workflow()
def endpoint():
    return {"status": "ok"}

if __name__ == "__main__":
    DBOS.launch()
    uvicorn.run(app)

Correct (configuration in main):

import os
from fastapi import FastAPI
from dbos import DBOS, DBOSConfig
import uvicorn

app = FastAPI()

@DBOS.step()
def process_data():
    return "processed"

@app.get("/")
@DBOS.workflow()
def endpoint():
    result = process_data()
    return {"result": result}

if __name__ == "__main__":
    config: DBOSConfig = {
        "name": "my-app",
        "system_database_url": os.environ.get("DBOS_SYSTEM_DATABASE_URL"),
    }
    DBOS(config=config)
    DBOS.launch()
    uvicorn.run(app, host="0.0.0.0", port=8000)

The workflow decorator can be combined with FastAPI route decorators. The FastAPI decorator should come first (outermost).

Reference: DBOS with FastAPI