If you like the tiling window manager like i3wm and you want to switch from Gnome there are somethings missing like the network manager applet, the volume control, add/connect bluetooth devices and in some cases the gnome-keyring to handle passwords, private keys and certificates.

To fix that, there are some config tweaks and programs that would make the switch to i3 better. For this i going to use Fedora 34

For the fastapi project we are going to use Sqlalchemy and postgresql taking some reference from the fastapi documentation.

# create a virtualenv, with any tool: poetry, pipenv, virtualenv module, etc 
pip install fastapi uvicorn aiofiles SQLAlchemy psycopg2-binary

project structure

.
├── Dockerfile
├── LICENSE
├── main.py
├── README.md
├── requirements.txt
└── timezone_utils
    ├── database.py
    ├── __init__.py
    ├── models.py
    ├── schemas.py
    └── utils.py

1 directory, 10 files

we define the models, schemas and engine for sqlalchemy and the api in the package timezone_utils

First timezones are evil, but sometimes you need to work with them. Sometimes is easy to consume some third party api to get timezone information based on a given location using geocoding but there also exists some alternatives.

Then inspired on this blog post and the project Timezone boundary builder decided to create a test project using fastapi and postgis to do the timezone lookup using the latitude and longitude.

Setup a python logging configuration with dictConfig

Logging configuration can be defined on different ways like a dict, ini file, yaml or json somethimes is more flexible to do it on code with python, all depends on the use case.

This small example show how to setup the logging configuration using dictConfig method and how to add an user defined object to the logging filter.

import os
import logging
import socket
from flask import Flask
from logging.config import dictConfig

class ContextFilter(logging.Filter):
    hostname = socket.gethostname()

    def filter(self, record):
        record.hostname = ContextFilter.hostname
        return True

logging_configuration = dict(
    version=1,
    disable_existing_loggers=False,
    formatters={
        "default": {"format": "[%(hostname)s %(asctime)s] %(levelname)s in %(module)s: %(message)s"},
    },
    filters={"hostname_filter": {"()": ContextFilter}},
    handlers={
        "console": {
            "class": "logging.StreamHandler",
            "formatter": "default",
            "filters": ["hostname_filter"],
        }
    },
    root={"handlers": ["console"], "level": os.getenv("LOG_LEVEL", "INFO")},
)

dictConfig(logging_configuration)
app = Flask(__name__)
logger = logging.getLogger(__name__)


@app.route("/")
def home():
    logger.debug("debug message")
    logger.info("info message")
    logger.warning("warning message")
    logger.error("error message")
    logger.critical("critical error message")
    return "Hello World"


if __name__ == "__main__":
    app.run()

The filter hostname_filter use the special key "()" which means that user-defined instantiation is wanted. ContextFilter subclass logging.Filter and overrides the filter method so when key hostname is found it will get his value from the ContextFilter class using socket.gethostname() and the application output will show:

Some git notes

For this blog, i’ve setup a linux KVM vps, using as distro Fedora 27. Fedora 27 comes with Selinux enforced security policy by default this is OK for system or apps where you required a high security level, but for my case to serve a static blog and run a couple of services like OpenSSH and Nginx is ok to set the security policy on permissive mode.

changing the policy can be done via command or setup in permanent way on the selinux config in /etc/selinux/config