Fastapi: How to reach the template directory from a router.py in a sub diretory?

[waterchinap]

I tried to follow the tutoria to form a bigger application
https://fastapi.tiangolo.com/tutorial/bigger-applications/
the project structure is like :

.
├── app
│   ├── __init__.py
│   ├── main.py
│   ├── model.py
│   ├── countries.gz
│   └── routers
│         ├── __init__.py
│         ├── items.py
│         └── users.py
│   └── templates
│         ├── layout.html
│         ├── home.html
│         └── world.html

main.py:

from fastapi import FastAPI, Request, APIRouter
from .routers import us_router, world_router

app = FastAPI()
# should I add some config here?

app.include_router(us_router.router)
app.include_router(world_router.wrouter)

in the /routers/items.py

from fastapi.templating import Jinja2Templates

wrouter = APIRouter()

templates = Jinja2Templates(directory='templates')
# if the router.py is in the same level of templates directory, this will work.
# should I change something here? I tried '../templates', not work.

@wrouter.get("/world", response_class=HTMLResponse)
async def world(request: Request):
    flist = fig.fig_world('total_cases')
    return templates.TemplateResponse('world.html', {'request': request,
                                                     'line_latest': flist[0],
                                                     }
                                      )

The problem:
cannot find the world.html, which is in templates directory.
If I use a absolute directory 'home/eric/fastapi/app/templates', it will work.

model.py:

import pandas as pd

df = pd.read_pickle('countries.gz')
# this is very confusing, I tried './countries.gz', not work

......

Problem:
cannot find the 'countries.gz' in the same directory. use absolute directory will work.

expected answer:
As a beginner, I am confused on the logic. I would like to know what is the best practice to handle the directories in the fastapi project?

Thanks a lot.

[includeamin]

can you put here your executes command?
do you run the command inside app directory or outside of that?

[waterchinap]

I execute just outside the app directory: uvicorn app.main:app --reload

OH!
change like this will work:

templates = Jinja2Templates(directory='./app/templates')

Thank you so much, the project root dir is the excute directory, NOT the main.py.directory.

My follow up question is:
Will it be more reasonable if I set the main.py directory as root? where should I config, If I want to do this,

[Mause]

You probably want to do something like this:

from os.path import dirname, join

current_dir = dirname(__file__)  # this will be the location of the current .py file
templates = join(current_dir, 'templates')

[waterchinap]

Thanks!
wonderful!