Ready for log and event management that doesn't suck or drain your budget? It's time to logstash.

After lots of refactoring and improvements to logstash since the first minor release last November, logstash is ready for wider usage now.

Read my announcement here.

The logstash site is also online and has docs, intros, slides, and videos.

http://logstash.net

Happy logstashing!

I've talked for a while about logging problems. Parsing, storing, searching, reacting.

Today is the first release of logstash.

What is logstash? Free and open source log/event management and search. It's designed to scale and help you more easily manage your logs and provides you a great way to search them for debugging, postmortems, and other analysis.

You can read more about it on logstash.googlecode.com.

Ruby has Logger. It is good, but strings suck. In a world where more and more people are using log data for inputs and analysis, structured data is good. I want to log structured data.

This lead to me subclassing Logger and additionally providing my own logger format class. The code for this is in logstash, logging.rb.

What did I add? Two main goals: First, improve context. Second, log structured data (objects). This is achieved by style changes (log objects, not strings), adding awesome_print support, adding code context to each log (line/file/method), etc.

To support the first goal (context), if the loglevel is 'debug' I will inspect the call stack and include the file and line of code that is logging. I also set the 'progname' to the name of the program by default. To support the second goal, log objects and improve how objects are formatted into strings with Object#inspect (or awesome_inspect, if available).

Some examples:

>> logger = LogStash::Logger.new(STDOUT)
I, [2010-11-12T15:19:48.388469 #18782]  INFO -- : ["Failed: require 'ap' (aka awesome_print); some logging features may be disabled", #<LoadError: no such file to load -- ap>]
# This is an example of what javascript folks call 'progressive enhancement'
# - we still function if awesome_print is not available.

>> logger.level = Logger::WARN
>> logger.warn("Hello")
W, [2010-11-12T15:20:05.465705 #18782]  WARN -- irb: Hello

>> logger.warn(["rejecting bad client", { :client => "1.2.3.4" }])
W, [2010-11-12T15:21:04.639404 #18782]  WARN -- irb: ["rejecting bad client", {:client=>"1.2.3.4"}]

>> logger.level = Logger::DEBUG
>> logger.warn("Hello")
W, [2010-11-12T15:21:57.754874 #18782]  WARN -- (irb):12#irb_binding: Hello
# Notice the context (file, line, method)       ^^^^^^^^^^^^^^^^^^^^
# When DEBUG level is set only due to performance and verbosity concerns.

The main benefit personally is logging objects instead of strings, which you can do, today, with the standard Logger. However, standard logger doesn't make nice with awesome_print or add file/line/method context. Anyway, logging objects lets you later hook a smarter error handling tool up to your logging that can inspect the structured data rather than having to regex your way through a single string.

If you have awesome_print available, the object output by my formatter gets even more useful for human viewing:

Why log structured? Easier to parse and query later, like in a logstash query.

Logstash uses EventMachine, which is an event-driven library for Ruby. Part of logstash's requirements is the ability to watch logfiles like 'tail -f' would. Previously, I was using File::Tail, but this was not EventMachine friendly.

Additionally, it's pretty common for applications to write to files with generated names that include timestamps, etc, so it was clear logstash would need a way to watch a pattern of files, like a glob such as /var/log/*.log

Thus was born eventmachine-tail.

You can install it with:

gem install eventmachine-tail

And try the 'rtail' tool that comes with it:

rtail -x "*.gz" "/var/log/**/*"

The project is hosted on github: jordansissel/eventmachine-tail.

This is the first project I've tried to use git with. I'm not really happy with git as it only seems to complicate my workflow, but I'll try to stick with it.