Aggregate logs and write to files later without directly writing to files

Question

Currently I have implemented and express.js application and I have added log4js logger for logging purposes. Now I wanted to write logs into Redis and then background worker which continuously pulls logs from the Redis List and write those logs into a local log files.

App.js would look like this

import { getLogger, configure } from 'log4js';
import {initServer} from './middleware/Express'
import { initRoutes } from './routes/RouterAggregator';

configure('./src/config/log4js-config.json');
const  logger = getLogger("app");

const init = ()=> {
  logger.info("Initializing Application");
  initServer();
  initRoutes();
};

And log configuration file would look like this.

{
  "appenders": [
    {
      "type": "console",
      "layout": {
        "type": "pattern",
        "pattern": "[%d]  [%[%p%]] %c {%x{ln}} - %m",
        "tokens": {
          "ln" : "loggerFunction()"
        }
      }
    },
    {
      "type": "dateFile",
      "filename": "log/access.log",
      "pattern": "-yyyy-MM-dd",
      "alwaysIncludePattern": false,
      "category": "http",
      "layout": {
        "type"    : "pattern",
        "pattern": "[%d]  [%p] %c {%x{ln}} - %m",
        "tokens": {
          "ln" : "loggerFunction()"
        }
      }
    },
    {
      "type": "dateFile",
      "filename": "log/app.log",
      "maxLogSize": 10485760,
      "numBackups": 3,
      "alwaysIncludePattern": false,
      "layout": {
        "type"    : "pattern",
        "pattern": "[%d]  [%p] %c {%x{ln}} - %m",
        "tokens": {
          "ln" : "loggerFunction()"
        }
      }
    },
    {
      "type": "logLevelFilter",
      "level": "ERROR",
      "appender": {
        "type": "file",
        "filename": "log/errors.log"
      },
      "layout": {
        "type"    : "pattern",
        "pattern": "[%d]  [%p] %c {%x{ln}} - %m",
        "tokens": {
          "ln" : "loggerFunction()"
        }
      }
    }
  ]
}

I want to know how to add redis to support above mentioned functionality.

Answer 1

Not sure the right way to do this but it seems you will have to write a custom appender that write to redis.

Example of built-in appenders for log4js are on github.