【Python】JSON logger formatter

やりたいこと

• Loggerクラスを定義してそれを他のクラスから呼び出して使う
• JSONフォーマット
• message以外に常に紐づけておきたい動的パラメータ、shopIdとitemIdも入れたい

JsonFormatter.py

import logging
import datetime
from pytz import timezone
from pythonjsonlogger import jsonlogger

class JsonFormatter(jsonlogger.JsonFormatter):

    def parse(self):
        return [
            'timestamp',
            'level',
            'name',
            'class',
            'shopId',
            'itemId',
            'message',
        ]
    
    shopId = None
    itemId = None

    def add_fields(self, log_record, record, message_dict):
        super().add_fields(log_record, record, message_dict)

        if not log_record.get('timestamp'):
            now = datetime.datetime.now(timezone('Asia/Tokyo')).strftime('%Y-%m-%dT%H:%M:%S%z')
            log_record['timestamp'] = now

        if log_record.get('level'):
            log_record['level'] = log_record['level'].upper()
        else:
            log_record['level'] = record.levelname

        # logを出力するファイルとその行
        log_record['class'] = record.pathname + ":" + str(record.lineno)

        # taskNameいらない
        del log_record['taskName']

        if self.shopId and self.itemId:
            log_record['shopId'] = self.shopId
            log_record['itemId'] = self.itemId

    def setItemId(self, shopId, itemId):
        print(shopId, itemId)
        self.shopId = shopId
        self.itemId = itemId
    


def getLogger(module_name):
    logger = logging.getLogger(module_name)
    handler = logging.StreamHandler()
    formatter = JsonFormatter()
    handler.setFormatter(formatter)
    logger.addHandler(handler)
    logger.setLevel(logging.DEBUG)
    return logger, formatter

test.py

from JsonFormatter import getLogger
import time

logger, formatter = getLogger(__name__)

error_code = 100
shopId = "11111"
itemId = "22222"

logger.error('Error occured due to xx', extra={'error_code': error_code})

formatter.setItemId(shopId, itemId)
time.sleep(3)
logger.error('Error occured due to xx', extra={'error_code': error_code})

実行します

$ python3 test.py

結果

{"timestamp": "2024-07-22T11:50:05+0900", "level": "ERROR", "name": "__main__", "class": "/Users/shuto.kawabata/Desktop/test.py:10", "shopId": null, "itemId": null, "message": "Error occured due to xx", "error_code": 100}
{"timestamp": "2024-07-22T11:50:08+0900", "level": "ERROR", "name": "__main__", "class": "/Users/shuto.kawabata/Desktop/test.py:14", "shopId": "11111", "itemId": "22222", "message": "Error occured due to xx", "error_code": 100}

となり

formatter.setItemId(shopId, itemId)

したことで期待値通りにshopIdとitemIdに値が代入されました