conflog 2.1.2

Python logging setup via environment variables and configuration files

Conflog

Conflog library provides Python logging setup via environment variables and configuration files.

Installation

pip3 install conflog

Usage

Create a configuration file, e.g. conflog.yaml:

---
handlers: "stream,file"
datefmt: "%Y-%m-%d %H:%M:%S"
filename: "conflog.log"
filemode: "w"
format: "[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s"
level: "info"
extras:
    env: "dev"
    id: "123"

And then use it in your Python code:

from conflog import Conflog

cfl = Conflog(conf_files=['conflog.yaml'])
logger = cfl.get_logger('somename')
logger.debug('Some debug message')
logger.info('Some info message')
logger.critical('Some critical message')

It will write the log messages to stdout and file conflog.log:

[SOMEAPP] [dev-123] 2023-06-07 10:49:01 INFO Some info message
[SOMEAPP] [dev-123] 2023-06-07 10:49:52 CRITICAL Some critical message

If you specify environment variables configuration, it will overwrite the configuration files:

import os
from conflog import Conflog

os.environ['CONFLOG_FORMAT'] = '[ENVAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s'
cfl = Conflog(conf_files=['conflog.yaml'])
logger.debug('Some debug message')
logger.info('Some info message')
logger.critical('Some critical message')

It will write the log messages using the format from CONFLOG_FORMAT environment variable:

[ENVAPP] [dev-123] 2023-06-07 10:49:01 INFO Some info message
[ENVAPP] [dev-123] 2023-06-07 10:49:52 CRITICAL Some critical message

And if you specify configuration dictionary, it will overwrite everything else:

import os
from conflog import Conflog

os.environ['CONFLOG_FORMAT'] = '[ENVAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s'
cfl = Conflog(
    conf_files=['conflog.yaml'],
    conf_dict={'format': '[DICTAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s'})
logger.debug('Some debug message')
logger.info('Some info message')
logger.critical('Some critical message')

It will write the log messages using the format from configuration dictionary:

[DICTAPP] [dev-123] 2023-06-07 10:49:01 INFO Some info message
[DICTAPP] [dev-123] 2023-06-07 10:49:52 CRITICAL Some critical message

If you're passing a string extras and need to have either comma or equal in either the key or the value, you can specify custom separators:

---
handlers: "stream,file"
datefmt: "%Y-%m-%d %H:%M:%S"
filename: "conflog.log"
filemode: "w"
format: "[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s"
level: "info"
extras: "dev_123|param1_value1"
extras_separator: "|"
extras_key_value_separator: "_"

Configuration

Configuration properties:

Property	Description	Default	Example
handlers	Comma separated list of handlers, supported values are stream and file	stream	stream,file
datefmt	Date format	%d-%b-%y %H:%M:%S	%Y-%m-%d %H:%M:%S
filename	Log file name	conflog.log	someconflog.log
filemode	Log file mode	w	w
format	Log message format	%(asctime)s --> %(name)s - %(levelname)s - %(message)s	[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s
level	Log level, supported values are debug, info, warning, error, critical	info	critical
extras_separator	Character used to separate extra fields key value pairs.	,	;
extras_key_value_separator	Character used to separate key and value in a pair.	=	_
extras	Extra fields to be added to log message. It can be comma separated key value pairs with equal separator, or a key value pairs map for JSON and YAML configuration files	None	env=dev,id=123 when using default separators, or env_dev;id_123 when using custom ; as extras_separator and _ as extras_key_value_separator

Configuration files can be in YAML, JSON, XML, or INI format. Multiple files can be specified in the conf_files parameter when initialising Conflog, the configuration will be merged in the order of the files, the latter file will overwrites the former file.

Environment variables configuration overwrites configuration files' properties. And finally, configuration dictionary overwrite everything else.

YAML

Example YAML configuration file:

---
handlers: "stream,file"
datefmt: "%Y-%m-%d %H:%M:%S"
filename: "conflog.log"
filemode: "w"
format: "[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s"
level: "info"
extras:
    env: "dev"
    id: "123"

JSON

Example JSON configuration file:

{
    "handlers": "stream,file",
    "datefmt": "%Y-%m-%d %H:%M:%S",
    "filename": "conflog.log",
    "filemode": "w",
    "format": "[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s",
    "level": "info",
    "extras": {
    "env": "dev",
    "id": "123"
    }
}

XML

Example XML configuration file:

<?xml version="1.0" encoding="UTF-8"?>
<conflog>
    <handlers>stream,file</handlers>
    <datefmt>%Y-%m-%d %H:%M:%S</datefmt>
    <filename>conflog.log</filename>
    <filemode>w</filemode>
    <format>[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s</format>
    <level>info</level>
    <extras>env=dev,id=123</extras>
</conflog>

INI

Example INI configuration file:

[conflog]
handlers: stream,file
datefmt: %%Y-%%m-%%d %%H:%%M:%%S
filename: conflog.log
filemode: w
format: [SOMEAPP] [%%(env)s-%%(id)s] %%(asctime)s %%(levelname)s %%(message)s
level: info
extras: env=dev,id=123

Environment Variables

Example configuration environment variables:

CONFLOG_HANDLERS="stream,file"
CONFLOG_DATEFMT="%Y-%m-%d %H:%M:%S"
CONFLOG_FILENAME="conflog.log"
CONFLOG_FILEMODE="w"
CONFLOG_FORMAT="[SOMEAPP] [%(env)s-%(id)s] %(asctime)s %(levelname)s %(message)s"
CONFLOG_LEVEL="info"
CONFLOG_EXTRAS="env=dev,id=123"
CONFLOG_EXTRAS_SEPARATOR=","
CONFLOG_EXTRAS_KEY_VALUE_SEPARATOR="="

FAQ

Q: Why am I getting duplicated log messages?

A: You might be getting the same log message displayed multiple times when there are other libraries adding handlers to the logger. You can clear those handlers prior to getting a logger from Conflog:

from conflog import Conflog

cfl = Conflog(conf_files=['conflog.yaml'])
cfl.close_logger_handlers()
logger = cfl.get_logger('somename')

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