node-bunyan-lite/examples/handle-fs-error.js

// Example handling an fs error for a Bunyan-created
// stream: we create a logger to a file that is read-only.

var fs = require('fs');
var path = require('path');
var bunyan = require('../lib/bunyan');

var FILENAME = 'handle-fs-error.log';
var S_IWUSR = 00200; // mask for owner write permission in stat mode

console.warn('- Log file is "%s".', FILENAME);
if (!path.existsSync(FILENAME)) {
        console.warn('- Touch log file.');
        fs.writeFileSync(FILENAME, 'touch\n');
}
if (fs.statSync(FILENAME).mode & S_IWUSR) {
        console.warn('- Make log file read-only.');
        fs.chmodSync(FILENAME, 0444);
}

console.warn('- Create logger.');
var log = bunyan.createLogger({
        name: 'handle-fs-error',
        streams: [
                  {path: FILENAME}
        ]
});

log.on('error', function (err) {
        console.warn('- The logger emitted an error:', err);
});

console.warn('- Call log.info(...).');
log.info('info log message');
console.warn('- Called log.info(...).');

setTimeout(function () {
        console.warn('- Call log.warn(...).');
        log.warn('warn log message');
        console.warn('- Called log.warn(...).');
}, 1000);