Separate info and error logs bunyan

Question

As I have seen many logs in blogs and I find bunyan suitable for logging but there is problem with it that it can't log to file according to their level.

Below is code structure I am following

const RotatingFileStream = require('bunyan-rotating-file-stream');
const bunyan = require('bunyan');

    var log = bunyan.createLogger({
          name: 'ShotPitch',


          streams: [{
            name: 'info',
            level: 'info',
            stream: new RotatingFileStream({
              path: 'info.%d-%b-%y.log',
              period: '1d', // daily rotation
              totalFiles: 10, // keep 10 back copies
              rotateExisting: true, // Give ourselves a clean file when we start up, based on period
              threshold: '10m', // Rotate log files larger than 10 megabytes
              totalSize: '20m', // Don't keep more than 20mb of archived log files
              gzip: true // Compress the archive log files to save space
            })
          }, {
            name: 'error',
            level: 'error',
            stream: new RotatingFileStream({
              path: 'error.%d-%b-%y.log',
              period: '1d', // daily rotation
              totalFiles: 10, // keep 10 back copies
              rotateExisting: true, // Give ourselves a clean file when we start up, based on period
              threshold: '10m', // Rotate log files larger than 10 megabytes
              totalSize: '20m', // Don't keep more than 20mb of archived log files
              gzip: true // Compress the archive log files to save space
            })
          }] 
        });

 log.info('Hello World');
 log.error('Hello World error log');

o/p: info.log :

{"name":"ShotPitch", "pid":7621,"level":30,"msg":"Hello World","time":"2017-09-03T18:29:04.181Z","v":0}

{"name":"ShotPitch", "pid":7621,"level":50,"msg":"Hello World","time":"2017-09-03T18:29:04.181Z","v":0}

o/p: error.log :

{"name":"ShotPitch", "pid":7621,"level":50,"msg":"Hello World","time":"2017-09-03T18:29:04.181Z","v":0}

Conclusion:

info.log shows both info and error logs

error.log shows only error logs

I want info logs only in info.log but unable to do. Is there anyone that can help ?. Also if tell me how to change to level: "info" rather than level:30

Answer 1

A log level for a rotating file stream needs to be specified when configuring bunyan.

By default, log output is to stdout and at the "info" level.

Setting a logger instance (or one of its streams) to a particular level implies that all log records at that level and above are logged. E.g. a logger set to level "info" will log records at level info and above (warn, error, fatal).

Error logs are thus also collected to the info log.

Answer 2

I met the same problem, finally I created 2 variables like:

var debugLog = bunyan.createLogger({
  name: 'general',
  streams: [
    {
      level: 'debug',
      path: './debug.log'
    }]
});

var errLog = bunyan.createLogger({
  name: 'general',
  streams: [
    {
      level: 'error',
      path: './error.log'
    }]
});

debugLog.info('hello world');
errLog.error('error');

Then logs will be in different log files.