WinstonJS custom level to file - node.js

Question

I changed the default levels in Winston.JS, to remove 2 levels and add 1 custom level. I want to log that new level in an separated file. So that file will only contains logs from that level.
const appRoot = require('app-root-path');
const winston = require('winston');
require('winston-daily-rotate-file');
const levels = {
levels: {
product: 0,
error: 1,
warn: 2,
info: 3,
debug: 4,
product: 5,
},
colors: {
product: 'magenta',
error: 'red',
warning: 'yellow',
info: 'green',
debug: 'blue',
}
}
const logger = winston.createLogger({
levels: levels.levels,
format: winston.format.combine(
winston.format.colorize(),
winston.format.timestamp({
format: 'DD-MM-YYYY HH:mm:ss'
}),
winston.format.printf(info => `[${info.timestamp}] [${info.level}]: ${info.message}`)
),
transports: [
new winston.transports.DailyRotateFile({
filename: `${appRoot}/logs/error-%DATE%.log`,
level: 'error',
datePattern: 'YYYY-MM-DD',
maxSize: '20m',
maxFiles: '14d'
}),
new winston.transports.DailyRotateFile({
filename: `${appRoot}/logs/product-%DATE%.log`,
level: 'product',
datePattern: 'YYYY-MM-DD',
maxSize: '20m',
maxFiles: '14d'
})
]
})
winston.addColors(levels.colors);
logger.stream = {
write: (message, encoding) => {
logger.info(message);
}
}
In this case, I want to place all the console.product() logs in the product-%DATE%.log file.
Currently the file is filled, but only with the information which is also showed in the log about from express (app.use(morgan("combined", {stream: winston.stream}));)
In development I also adding an extra transport for debug on the console:
let env = process.env.NODE_ENV;
if (env !== 'production'){
logger.add(new winston.transports.Console({
level: 'debug',
prettyPrint: function ( object ){
return JSON.stringify(object);
}
}))
}
How can I get only the console.product() logs into the product.log file?

Answer 1

I have fixed this with the help of this code snippet: https://github.com/winstonjs/winston/issues/614#issuecomment-405015322
So my whole config now looks like this:
const appRoot = require('app-root-path');
const winston = require('winston');
const path = require('path')
require('winston-daily-rotate-file');
const levels = {
levels: {
product: 1,
error: 1,
warn: 3,
info: 4,
debug: 5
},
colors: {
product: 'magenta',
error: 'red',
warning: 'yellow',
info: 'green',
debug: 'blue',
}
}
let getLabel = function(callingModule){
//To support files which don't have an module
if(typeof callingModule == 'string'){
return callingModule;
}
let parts = callingModule.filename.split(path.sep);
return path.join(parts[parts.length -2], parts.pop());
}
const errorFilter = winston.format( (info, opts) => {
return info.level == 'error' ? info : false;
})
const productFilter = winston.format( (info, opts) => {
return info.level == 'product' ? info : false
})
module.exports = function(callingModule){
const logger = winston.createLogger({
levels: levels.levels,
format: winston.format.combine(
winston.format.colorize(),
winston.format.timestamp({
format: 'DD-MM-YYYY HH:mm:ss'
}),
winston.format.label({label: getLabel(callingModule)}),
winston.format.printf(info => `[${info.timestamp}] [${info.level}] [${info.label}]: ${info.message}`)
),
transports: [
new winston.transports.DailyRotateFile({
name: "Error logs",
filename: `${appRoot}/logs/error-%DATE%.log`,
level: 'error',
label: getLabel(callingModule),
datePattern: 'YYYY-MM-DD',
maxSize: '20m',
maxFiles: '14d',
format: winston.format.combine(
errorFilter(),
winston.format.colorize(),
winston.format.timestamp({
format: 'DD-MM-YYYY HH:mm:ss'
}),
winston.format.label({label: getLabel(callingModule)}),
winston.format.printf(info => `[${info.timestamp}] [${info.level}] [${info.label}]: ${info.message}`)
),
}),
new winston.transports.DailyRotateFile({
name: "Product logs",
filename: `${appRoot}/logs/product-%DATE%.log`,
level: 'product',
label: getLabel(callingModule),
datePattern: 'YYYY-MM-DD',
maxSize: '20m',
maxFiles: '14d',
format: winston.format.combine(
productFilter(),
winston.format.colorize(),
winston.format.timestamp({
format: 'DD-MM-YYYY HH:mm:ss'
}),
winston.format.label({label: getLabel(callingModule)}),
winston.format.printf(info => `[${info.timestamp}] [${info.level}] [${info.label}]: ${info.message}`)
),
})
]
})
winston.addColors(levels.colors);
let env = process.env.NODE_ENV;
if (env !== 'production'){
logger.add(new winston.transports.Console({
name: "Debug logs",
level: 'debug',
label: getLabel(callingModule),
prettyPrint: function ( object ){
return JSON.stringify(object);
}
}))
}
else if (env !== 'development') {
logger.add(winston.transports.DailyRotateFile({
name: "Combined logs",
filename: `${appRoot}/logs/combined-%DATE%.log`,
level: 'error',
datePattern: 'YYYY-MM-DD-HH',
maxSize: '20m',
maxFiles: '14d'
}))
}
logger.stream = {
write: (message, encoding) => {
logger.info(message);
}
}
return logger;
}
I also noticed that I was declaring the product level twice with priority 1 and 5.
On the different transports, I added an filter which is based on the code which I found on Github. It will filter the printed logs to only the set level.
To show the filename of the calling file in the log I added the callingModule.
Now I can require the console with
const console = require(path.join(__dirname, 'winston.config'))(module);
The call
console.info('NODE_ENV is undefined or its value was not understood. Default to development mode. ');
Will look as [28-08-2019 11:39:51] [info] [config\env.config.js]: NODE_ENV is undefined or its value was not understood. Default to development mode. in the log.