wuetender-junger-mann.de

I recently had the pleasure of supporting a new system throughout its first month of production. This was a good opportunity to refresh my command line skills. As it happened I spent a lot of time looking at log files trying to figure out what happened to the productions system. I figured, that a graphical representation of the events would be nice and started using gnuplot.

First I started out with a bunch of bash scripts, using what your usual unix installation provides, but then I actually came up with some groovy scripts to provide better abstractions. A log file generally looks somewhat like this:

04/01/1970 07:55:13 garbage
04/01/1970 09:27:48 Event 2
04/01/1970 10:01:28 garbage
04/01/1970 10:38:30 garbage
04/01/1970 10:48:36 garbage
04/01/1970 10:51:58 Event 2
04/01/1970 11:03:45 garbage
04/01/1970 11:34:03 Event 1
04/01/1970 12:24:33 garbage
05/01/1970 04:35:50 ERROR

There is a lot of garbage plus some events we might be interested in. It allows to specify events, e.g. by providing a regexp:

Event EVENT1 = new RegExEvent("Event 1", ~/Event 1/)
Event EVENT2 = new RegExEvent("Event 2", ~/Event 2/)
Event ERROR = new RegExEvent("Error", ~/ERROR/)

The next step is newing up a TimeLineVisualizer on these events and passing in a stream with the actual log:

def logFile = new File("test.log");
 
logFile.withInputStream {InputStream stream ->
  def visualizer = new TimeLineVisualizer([
          EVENT1,
          EVENT2,
          ERROR
  ]);
  visualizer.visualize(stream)
}

If you have the gnuplot binary on your path this will yield something like this:

Also in some cases you would like to know which time of day events are most likely to happen. For producing histograms I created another visualizer (which currently takes only one event).

logFile.withInputStream {InputStream stream ->
  def visualizer = new HistogramVisualizer(EVENT2, HistogramVisualizer.HOUR_OF_DAY_BINS)
  visualizer.visualize(stream)
}

For the example log file, which unfortunately has an even distribution of events, we get this:

The cool thing about gnuplot is, that you can actually run these things in a cron job to produce daily reports (and mail them to the appropriate people) or on a continuous integration server to visualise how the system is being exercised by the test suite.

Curt Cobain war definitiv jemand, der immer ein trauriges Lied zu singen wusste…

Waren Samstag im Sticky Fingers, wo noch die gute Musik gespielt wird.

I just discovered Anna Ternheim, a nice Swedish Singersongwriter. I am listening to here Album Separation Road and try to call an external process from groovy which after all uses the Java API to perform such tasks.

Given the slightly depressing nature of the music and the slight drizzle outside, I can’t go on ranting I’m just sitting here sobbing about the sorry state of the world and the hardship of having to deal with java.lang.Runtime and java.lang.Process.

Wir waren heute bei Art Brut in Frankfurt. Ganz großes Tennis. Die Jungs gehn ab. Dank sei nochmal dem Jogi, der sie entdeckt hat.

… ist nicht nur der hamburger Direktkandidat der Partei für den Deutschen Bundestag, sondern hat
Angie auch eine Hymne mit Aussage entgegengesetzt.

Jogi hat mich auf Art Brut aufmerksam gemacht. Originelle Texte (Auf der Homepage verfügbar) und veritable Gitarrenmusik. Habe es gleich mit in den Urlaub genommen und meine Mitreisenden beglückt. Die Reaktionen waren gemischt, also *nicht* durchweg negativ!

I know I can, I know I can.
I’m fine when I am with my own hand.

In diesem Zusammenhang ist auch der Anzeigencartoon auf der aktuellen Titanic (9/2005) lobend zu erwähnen, der leider nicht online verfügbar.