Node.js - logging / Use morgan and winston

Question

we use morgan in order to log our express transformation:

var morgan  = require('morgan');
morgan('combined');
// a format string
morgan(':remote-addr :method :url :uuid');
// a custom function
morgan(function (req, res) {
  return req.method + ' ' + req.url + ' ' + req.uuid;
})

Also, we use winston in order to log our other logging:

var winston = require('winston');
var logger = new (winston.Logger)({
  transports: [
         new (winston.transports.Console)({ level: 'info' }),
          new (winston.transports.File)({ filename: '/var/log/log-file.log' })
  ]
});

Is there any way to combine the two loggers together? the situation now is that morgan is write to my standard output, when winston writes to /var/log/log-file.log.

I wish that the logger file will combine from the express transformation information, and from the other information I want (logger.info())..

Answer 1

This article does an excellent job for what you want to do.

http://tostring.it/2014/06/23/advanced-logging-with-nodejs/

For your specific code you probably need something like this:

var logger = new winston.Logger({
    transports: [
        new winston.transports.File({
            level: 'info',
            filename: './logs/all-logs.log',
            handleExceptions: true,
            json: true,
            maxsize: 5242880, //5MB
            maxFiles: 5,
            colorize: false
        }),
        new winston.transports.Console({
            level: 'debug',
            handleExceptions: true,
            json: false,
            colorize: true
        })
    ],
    exitOnError: false
}),

logger.stream = {
    write: function(message, encoding){
        logger.info(message);
    }
};

app.use(require("morgan")("combined", { "stream": logger.stream }));

This will set up Winston to write a log to the console as well as a file. Then you can use the last expression to pass output from the morgan middleware into winston.

Answer 2

In Typescript:

let logger = new (winston.Logger)({
    exitOnError: false,
    level: 'info',
    transports: [
        new (winston.transports.Console)(),
        new (winston.transports.File)({ filename: 'app.log'})
    ]
})

class MyStream {
    write(text: string) {
        logger.info(text)
    }
}
let myStream = new MyStream()
app.use(morgan('tiny', { stream: myStream }));

Answer 3

Update the last line to remove warning

app.use(require("morgan")("combined", { stream: logger.stream }));

Answer 4

Morgan has the bad habit of ending the message with a \n so to make things orderly you may want to remove that before writing it to winston.

This can be done in many different ways like on the format side in winston, or by updating your stream to not write the \n

class MyStream {
    write(text: string) {
        logger.info(text.replace(/\n$/, '');
    }
}
let myStream = new MyStream()
app.use(morgan('tiny', { stream: myStream }));

Answer 5

for Typescript another way to go about it, without needing to create a class is

let logger = new (winston.Logger)({
    exitOnError: false,
    level: 'info',
    transports: [
        new (winston.transports.Console)(),
        new (winston.transports.File)({ filename: 'app.log'})
    ]
})

const myStream = {
    write: (text: string) => {
        logger.info(text)
    }
}

app.use(morgan('combined', { stream: myStream }));

This solution was hived from this Github page https://github.com/winstonjs/winston/issues/1385. However, it is important to note that there is a slight difference between our codes. Instead of:

app.use(morgan('combined', { myStream }));

I use:

app.use(morgan('combined', { stream: myStream }));

This helped me out as am not too big on creating classes.