How to use flask logging to record what changes a user makes (before and after) when calling an interface

Question

This is a business requirement from the manager. The actual project is similar to the management system, but he requires detailed logging.At present, I have recorded the request parameters of the back-end interface that the front-end calls, and prepare to design a log table in the database to store it (so that I can locate the problem according to the parameters passed by the front-end and the records that judge whether the front-end request interface succeeds or not in the table). However, I can't think of how to add the content (before and after modification) modified by the current login user to the maintenance log, and how to realize this requirement.It is difficult to modify a single table in an interface, but how to handle the modification of multiple tables? Flask has been working for more than a year, and I hope to seek the help of various netizens.

Answer 1

You may use the logging library in Flask to achieve this. Setting the config:

logging.basicConfig(filename='record.log', level=logging.DEBUG, format=f'%(asctime)s %(levelname)s %(name)s %(threadName)s : %(message)s')

And then whereever you need to log the event, use:

current_app.logger.info("Your message here")

Answer 2

@elephant111 CDC is "Change Data Capture" feature that you can enable on your DB and it would store all of the histories of data modification on DB. An audit log or Activity log, is some sort of log that you keep what your user has been done in the system. the format could be easy if you are exposing APIs, you can just keep the request body and response body of each request and the detail of authenticated user in somewhere ( Elastic, Log file or even your Database ). And it helps you track everything. for example audit log

Audit Log/Activity Log Format Elastic / MongoDB / LogFile

{
"reqUrl" : "/book/13245/",
"reqMethod": "POST",
"reqBody": { 
    "name":"Writing on the Wall",
    "author":"Sam Smith"
},
"respBody":{
    "retCode": 0,
    "retMsg": "Book updated successfully"

},
"username":"elephant111",
"ip_address":"10.10.10.10",
"datetime":"2021-07-30 11:30:00"
}

Audit Log / Activity Log MySQL Format

| id | reqUrl       | method | reqBody                                             | respBody                                             | username    | ip_address  | date_created        |
|----|--------------|--------|-----------------------------------------------------|------------------------------------------------------|-------------|-------------|---------------------|
| 1  | /book/13245/ | POST   | {"name":"Writing on the Wall","author":"Sam Smith"} | {"retCode": 0,"retMsg": "Book updated successfully"} | elephant111 | 10.10.10.10 | 2021-07-30 11:30:00 |
|    |              |        |                                                     |                                                      |             |             |                     |
|    |              |        |                                                     |                                                      |             |             |                     |

How To Enable Audit Log / Activity Log on Flask

To Enable Audit Log on the Flask you can use the following snippet code:

logger_config.py

import os
from logging.config import dictConfig

# Import Log Base Path From Config File
# The output should be something like this 
# log_base_path = "/var/log/"

log_base_path = your_config.LOG_BASE_PATH

logging_dict = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'JSONPERLINE': {
            'format': '%(message)s'
        },
      
    },
    'handlers': {
        'audit_log': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': os.path.join(log_base_path, 'audit_log.log'),
            'formatter': 'JSONPERLINE'
        }
    },
    'loggers': {
        'audit_log': {
            'handlers': ['audit_log'],
            'level': 'INFO'
        }
    }
}

dictConfig(logging_dict)

init.py ( or wherever you define your blueprints )

@app.after_request
def after_request(response):
    """ Logging all of the requests in JSON Per Line Format. """
    audit_logger = logging.getLogger('inbound_requests')
    
    audit_logger.info({
            "datetime": datetime.datetime.now().isoformat(),
            "user_ip": request.remote_addr,
            "user_name": g.username, // get current authenticated user. you need to customize it based on your code
            "method": request.method,
            "request_url": request.path,
            "response_status": response.status,
            "request_referrer": request.referrer,
            "request_user_agent": request.referrer,
            "request_body": request.json,
            "response_body": response.json
        })
    return response