node-bunyan-lite/examples/long-running.js

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2013-01-19 00:27:53 +00:00
/*
* A long-running process that does some periodic logging. Use bunyan with
* it some of these ways:
*
* 1. Direct piping:
* node long-running.js | bunyan
* 2. Logging to file (e.g. if run via a service system like upstart or
* illumos' SMF that sends std output to a log file), then tail -f that
* log file.
* node long-running.js > long-running.log 2>&1
* tail -f long-running.log | bunyan
* 3. Dtrace to watch the logging. This has the bonus of being able to watch
* all log levels... even if not normally emitted.
* node long-running.js > long-running.log 2>&1
* bunyan -p $(head -1 long-running.log | json pid)
*
*/
var fs = require('fs');
var bunyan = require('../lib/bunyan');
function randint(n) {
return Math.floor(Math.random() * n);
}
function randchoice(array) {
return array[randint(array.length)];
}
//---- mainline
var words = fs.readFileSync(__dirname + '/long-running.js', 'utf8').split(/\s+/);
var levels = ['trace', 'debug', 'info', 'warn', 'error', 'fatal'];
var timeout;
var log = bunyan.createLogger({name: 'lr', level: 'debug'});
// We're logging to stdout. Let's exit gracefully on EPIPE. E.g. if piped
// to `head` which will close after N lines.
process.stdout.on('error', function (err) {
if (err.code === 'EPIPE') {
process.exit(0);
}
})
function logOne() {
var level = randchoice(levels);
var msg = [randchoice(words), randchoice(words)].join(' ');
var delay = randint(300);
//console.warn('long-running about to log.%s(..., "%s")', level, msg)
log[level]({"word": randchoice(words), "delay": delay}, msg);
timeout = setTimeout(logOne, delay);
}
log.info('hi, this is the start');
timeout = setTimeout(logOne, 1000);