Python - Category - JMS Blog/categories/python/Python - Category - JMS BlogHugo -- gohugo.ioenWed, 12 Aug 2020 00:00:00 +0000Timezone lookup using latitude and longitud (part 2)/posts/2020-08-12-timezone-finder-2/Wed, 12 Aug 2020 00:00:00 +0000jms/posts/2020-08-12-timezone-finder-2/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

]]>Timezone lookup using latitude and longitude (part 1)/posts/2020-08-11-timezone-finder-1/Tue, 11 Aug 2020 00:00:00 +0000jms/posts/2020-08-11-timezone-finder-1/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.

]]>Flask logging setup/posts/2019-05-27-flask-logging/Mon, 27 May 2019 00:00:00 +0000jms/posts/2019-05-27-flask-logging/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:

]]>Checking and validating phone numbers/posts/2015-06-09-checking-and-validating-phone-numbers/Tue, 09 Jun 2015 00:00:00 +0000jms/posts/2015-06-09-checking-and-validating-phone-numbers/In applications sometimes is needed check and verify if a phone number is valid or possible if the number have all required digits to be valid for this purpose there are several options to tackle the problem like regular expressions for example to validate E.164 format, library like the [Google libphonenumber](http://Google libphonenumber) and API like the Twillio Lookup for something more complete.

for this post i created a small app for test a demo purpose using the [python port of the Google library](https://github.com/daviddrysdale/python- phonenumbers)

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