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14. File Formats

14.2.configparser - Configuration file parser

This module provides the ConfigParser class which implements a basic configuration language which provides a structure similar to what's found in Microsoft Windows INI files. You can use this to write Python programs which can be customized by end users easily.

config.ini​

[mysqlDB] host = '0.0.0.0' db = 'test' user = 'root' pass = 'pswd'

test.py​

import configparser
import MySQLdb.cursors
config = configparser.ConfigParser()
config.read('config.ini')
def connect():
  return MySQLdb.connect(host = config['mysqlDB']['host'],
                          user = config['mysqlDB']['user'],
                          passwd = config['mysqlDB']['pass'],
                           db = config['mysqlDB']['db'])

Using Python files​

config.py​

username = "xy" password = "abcd"

main.py​

import config
login(config.username, config.password)

Using built-in data structure​

# config.py
DATABASE_CONFIG = {
    'host': 'localhost',
    'dbname': 'company',
    'user': 'user',
    'password': 'password',
    'port': 3306
}

# main.py
import pymysql
import config

def connect_db(dbname):
    if dbname != config.DATABASE_CONFIG['dbname']:
        raise ValueError("Couldn't not find DB with given name")
    conn = pymysql.connect(host=config.DATABASE_CONFIG['host'],
                            user=config.DATABASE_CONFIG['user'],
                            password=config.DATABASE_CONFIG['password'],
                            db=config.DATABASE_CONFIG['dbname'])
    return conn

connect_db('company')

Using json​

// credentials.json
{
  "DEFAULT": {
    "SECRET_KEY": "secret-key-of-myapp",
    "ADMIN_NAME": "administrator",
    "AWS_DEFAULT_REGION": "ap-northeast-2",
    "MAX_IMAGE_SIZE": 5242880
  },
  "TEST": {
    "TEST_TMP_DIR": "tests",
    "TEST_TIMEOUT": 20
  },
  "CI": {
    "SERVICE": "travis-ci",
    "HOOK_URL": "web-hooking-url-from-ci-service"
  }
}
# main_with_json.py
import json

with open('credentials.json', 'r') as f:
    credentials= json.load(f)

secret_key = credentials['DEFAULT']['SECRET_KEY'] # 'secret-key-of-myapp'
ci_hook_url = credentials['CI']['HOOK_URL'] # 'web-hooking-url-from-ci-service'

Using dynamicloading​

# /opt/settings/config.py
DATABASE_CONFIG = {
    'host': 'localhost',
    'dbname': 'company',
    'user': 'user',
    'password': 'password',
    'port': 3306
}

# main.py
import sys
import pymysql

sys.path.append('/opt/settings')
import config

def connect_db(dbname):
    if dbname != config.DATABASE_CONFIG['dbname']:
        raise ValueError("Couldn't not find DB with given name")
    conn = pymysql.connect(host=config.DATABASE_CONFIG['host'],
                            user=config.DATABASE_CONFIG['user'],
                            password=config.DATABASE_CONFIG['password'],
                            db=config.DATABASE_CONFIG['dbname'])
    return conn

connect_db('company')

https://hackernoon.com/4-ways-to-manage-the-configuration-in-python-4623049e841b

https://docs.python.org/3/library/configparser.html

https://hackersandslackers.com/simplify-your-python-projects-configuration