CODEWITHSUNDEEP
node.jswinston
user2741831
user2741831

Reputation: 2398

Winston never writing to log file if script crashes

I have a project that I need log files for, which is why I want to use winston. But over its runtime it may crash at some point, so I was doing some testing:

const winston = require('winston');

const logger = winston.createLogger({
    transports: [
        new winston.transports.Console(),
        new winston.transports.File({ filename: 'combined.log' })
    ]
});

let i=100000;
while(i-->0){
    logger.info('Hello world');
}

throw new Error('Error');

This basically just prints hello world 100000 times and than errors out. The problem I have is that combined.log is only written to if the program doesn't crash (presumably at the very end). So why is winston only writing to the actual log once its done running. And how can I make it write to the file even if there may be an exception?

EDIT:

interestingly, it works if you add a 1 second delay between the error

const winston = require('winston');
const fsp = require('fs').promises;

let a=async ()=>{

    try{
        await fsp.unlink('combined.log');
    }catch(e){

    }

const logger = winston.createLogger({
    transports: [
        new winston.transports.Console(),
        new winston.transports.File({ filename: 'combined.log' })
    ]
});

    let i=100000;
    while(i-->0){
        logger.info('Hello world');
    }

    //wait 1 seconds
    await new Promise((resolve)=>setTimeout(resolve,1000));
//  await new Promise((resolve,reject)=>{resolve()});

    throw new Error('Error');
}

a()

Upvotes: 0

Views: 650

Answers (1)

dangarfield
dangarfield

Reputation: 2330

Use handleExceptions: true

const winston = require('winston');

const logger = winston.createLogger({
    transports: [
        new winston.transports.Console({handleExceptions: true}),
        new winston.transports.File({ filename: 'combined.log',handleExceptions: true})
    ]
});

let i=100000;
while(i-->0){
    logger.info('Hello world');
}

throw new Error('Error');

Although, really, you should always catch any exceptions etc

Upvotes: 3

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