Helper function create_user gets error: DatabaseBackend is not running

[augusto-herrmann]

Hi, thanks for maintaining fastapi_users!

I'm coding a command line tool to create a super user. I've managed to do it successfully when using SQL Alchemy directly, but I'd like to refactor it to use fastapi_users like we're doing in the main application, so that we can benefit from the validation of fields, etc.

However, when trying to use the helpers recommended in the documentation, I get an error: "DatabaseBackend is not running".

The code:

import asyncio

from fastapi_users import FastAPIUsers
from fastapi_users.authentication import JWTAuthentication

# just a few very simple custom User classes with custom fields for the User
# user_db = SQLAlchemyUserDatabase(UserDB, database, users)
from auth import user_db, User, UserCreate, UserUpdate, UserDB, SECRET_KEY

jwt_authentication = JWTAuthentication(
    secret=SECRET_KEY,
    lifetime_seconds=3600,
    tokenUrl="/auth/jwt/login"
)

fastapi_users = FastAPIUsers(
    user_db,
    [jwt_authentication],
    User,
    UserCreate,
    UserUpdate,
    UserDB,
)

async def create_superuser(fastapi_users: FastAPIUsers):
    superuser = await fastapi_users.create_user(
        UserCreate(
            email="email@example.com",
            password="1234",
            cod_unidade=1,
            is_superuser=True
        )
    )
    return superuser

loop = asyncio.get_event_loop()
loop.run_until_complete(
    create_superuser(fastapi_users)
)
loop.close()

Result:

  File "/usr/local/lib/python3.7/site-packages/fastapi_users/user.py", line 48, in create_user
    existing_user = await user_db.get_by_email(user.email)
  File "/usr/local/lib/python3.7/site-packages/fastapi_users/db/sqlalchemy.py", line 127, in get_by_email
    user = await self.database.fetch_one(query)
  File "/usr/local/lib/python3.7/site-packages/databases/core.py", line 145, in fetch_one
    async with self.connection() as connection:
  File "/usr/local/lib/python3.7/site-packages/databases/core.py", line 219, in __aenter__
    await self._connection.acquire()
  File "/usr/local/lib/python3.7/site-packages/databases/backends/postgres.py", line 148, in acquire
    assert self._database._pool is not None, "DatabaseBackend is not running"
AssertionError: DatabaseBackend is not running

What am I doing wrong here?

[frankie567]

When defining the FastAPI app, there are startup/shutdown events that take care of opening the database connection:

@app.on_event("startup")
async def startup():
    await database.connect()


@app.on_event("shutdown")
async def shutdown():
    await database.disconnect()

In your script, you have to take care of this yourself and call it in your function.

[augusto-herrmann]

Thanks!

I don't want the whole FastAPI running while in the CLI tool, so I just did the await database.connect() and .disconnect() bits and it worked just fine.