express logging middlewares built on bunyan and rotatelog-stream

$ npm install bunlogger --save

1. app.use(logger.connect()) middleware will populate the req.log, which is actually a child of the bunyan logger, simply req.log.info('...') will share the same cor_id in the access log and error log.

2. req.log.fatal(), req.log.error() will log error into error log file separated from access log.

3. app.use(logger.onError()) middleware will skip error which was logged by req.log.fatal(), req.log.error() or req.log.warn(), so no duplicated error logging. In addition, error with no status or status >= 500, will be logged in error level. Error with status between 400~499, will be logged in warn level.

4. elapsed show the time spent in this req.

5. Integrate with rotatelog-stream for rotating logs to files.

6. See logging on the console in developing stage.

const express = require('express');
const AppLogger = require('bunlogger');
const logDir = require('path').join(__dirname, 'log');

   
var app = express();
app.log = new AppLogger({dev: true, logDir});

populate req.log and log all accesses

app.use(app.log.connect());

Catch express next(err) for logging, but skip if req.log got called above warn level.

app.use(app.log.onError());

log directory created and bunlogger.log, bunlogger-error.log created.

Finally, render req.cor_id in the final error handler, so the customer can contact you with cor_id for help.

logger is using rotatelog-stream for rotating logs.

const Logger = require('..').Logger;
const join = require('path').join;

var log = new Logger({logDir: join(__dirname, 'log')});

log.info('hi info');
log.warn('hi warn');
log.error('hi error');

A handy tool to replace console.error(err).

const printErr = require('bunlogger').printErr;

try {
  new NotExist();
} catch (er) {
  printErr(er)
}

$ DEBUG=* node bin/www

• name: {String},
• logDir: 'path/to/log/directory' - directory to save log files
• keep: {Number} - how many log files keep. See rotatelog-stream
• maxsize: {Number} - max filesize allowed. See rotatelog-stream
• dev: {Boolean} - Pipe logs to process.stdout for development, so we can see how logging file looks like in console.
• streams: {Array} - additional streams for Bunyan