logrotate-stream
================

A Writable Stream that supports linux logrotate style options


example
=======
On the command line:
`` sh
node app.js 2>&1 | logrotate-stream app.log --keep 3 --size '50m' --compress
`

As a module:
` js
var stream = require('logrotate-stream')
, toLogFile = stream({ file: './test.log', size: '100k', keep: 3 });

someStream.pipe(toLogFile);
`

the problem
===========
Rotating logs that are being written to with stdio redirection sucks. Using a
utility like logrotate doesn't automagically update your processes log file
descriptor and you end up with several empty logs and one mega rotated log.

There's a couple ways to try and deal with this, but they all fall short:
#### 1. Use winston's log rotation feature for nodejs apps

This requires adding a new dependency and possibly code changes around logging
logic.

#### 2. Restart your app on a process signal

Often times, production apps can't be restarted willy-nilly

#### 3. Use the copytruncate feature of logrotate

This only works if you don't need to guarantee that all of your log lines are
persisted. copytruncate performs a non-atomic copy before truncating the
original log, which means you can lose data in the process if the copy is slow.

logrotate-stream tries to remedy this situation by acting as an intermediary
between the application and the file system, piping stdin to log files and
rotating those logfiles when necessary.

upstart woes
============
If you find yourself using logrotate-stream with upstart, there's a few things
to consider. Piping to logrotate-stream in your exec line will cause upstart
to track the pid of the logrotate process rather than your app. While stopping
will still work (most likely emitting an EPIPE error on your app before
exiting), it would be better if you used a named pipe to redirect your apps output:
`
chdir /path/to/app

pre-start script
# create a named pipe
mkfifo logpipe
# create a backgrounded logrotate-stream process and
# redirect the named pipe data to it
logrotate-stream app.log --keep 3 --size 50m < logpipe &
end script

start the app, redirecting stdout & stderr to the named pipe


exec /usr/local/bin/node index.js > logpipe 2>&1
`

This setup will register the correct pid with upstart, make sure your stdio
is forwarded to logrotate-stream, and will properly kill the logrotate-stream
process when your app is stopped.

options
=======

$3

The file log file to write data to.

$3

The max file size of a log before rotation occurs. Supports 1024, 1k, 1m, 1g

$3

The number of rotated log files to keep (including the primary log file).
Additional logs are deleted no rotation.

$3

Optionally compress rotated files with gzip.

install
=======

With npm do:

`
npm install logrotate-stream
``