Ramblings

Weaving with Light Pt. 1

This is the first in a series of posts regarding a recent project which integrated handweaving, fiber optics, and electronics. It’s a part of a costume for a cosplayer at work, but I’ll be discussing my part of it. TL;DR For those who can’t wait, here’s what the project looks like in the dark: And …

View full post

Abusing HAProxy: Stupid Simple Easy Dashboards

I wanted a simple way to have a dashboard to show if hosts and services are alive & didn’t want to write much code and/or run up a nagios instance (or anything like that). All I care is whether it’s green or red. I’d already been setting up HAProxy for a proxy forwarder, so I …

View full post

Rules for Operations

The following list was compiled in 2012 for a talk on Operations Principles for Developers (Ops4Devs). They are loosely inspired by the list of rules from Zombieland as well as from my experiences and those shared by others. Looking over the list four years later, I believe that they are still (very) applicable for all …

View full post

DevOps Creed (Work in Progress)

This is a work in progress of a DevOps Creed. It will always be a work in progress as I and others learn and grow. Suggestions are welcome! I have drunk deep of the DevOps Kool-Aid. From the visions which ensued, I have come to the following…. I Believe: DevOps methodologies lead to systems which …

View full post

I am not a Mindreader: a mini-saga

I must confess a severe failing on my part. I am not a mindreader. I am not privy to the thoughts in your head. I do not know your needs or desires. And I am certainly not aware of your expectations. This is why requirement documents exist. Please use them.

View full post

Weaving with Light Pt. 1 Abusing HAProxy: Stupid Simple Easy Dashboards Rules for Operations DevOps Creed (Work in Progress)I am not a Mindreader: a mini-saga

Aug 31

Quick thought on programming and distractions

Categories:

life hacking, philosophy

by Matt Williams

“The way is not in the sky. The way is in the heart.”
— Buddha

Too often it’s easy to spend ~~hours~~ ~~days~~ ~~weeks~~ far too long reading blogs and ~~wilfing~~ doing research. Looking for that perfect tool. Looking for a wonderful library. Looking for a new technique. Looking, looking, looking. Almost like Hans Guck-in-die-Luft, not paying attention to everything around and not where you’re going, let alone the task at hand.

A wise man, recognizing that the internet is but an illusion, does not act as if it is real, so he escapes the suffering.

The net is an illusion, created by its participants, and a large part of its illusion lies in creating desire. These desires are, indeed, illusions — when was the last time you could hold that ultimate WoW weapon in your hand? Or the person on the other side of the world with whom you spend hours and hours chatting — are they real? Illusion, all of it. And yet we spend hours and hours — gotta get to the next level… One more gold and I’ll have enough to buy it… Surely that library will allow me to make the perfect code….

The good thing about the net is that we have access to more information, people, places, and things than ever before in human history. The bad thing about the net is that we have access to more information, people, places, and things than ever before in human history. Or at least we think we do.

There are more things in heaven and earth, Horatio, than are dreamt of in your internet….

Sometimes it’s important to get off the net, to leave the illusions behind and spend some time in meatspace. It’s still possible to be distracted in meatspace — in fact, it is very easy, but there isn’t quite the immediate temptation to click one more link, to see what’s behind the next url.

“Illusion is the first of all pleasures.” —Oscar Wilde

Next time I sit down to code, I’m first going to take some time and look inside, finding the thread of the code within. Then with my connection to the net severed, I’m going to write. I’ll spend at least an hour simply writing without any distractions. If I come to something I need to lookup, if I don’t have it at hand, I’ll mark it and move on. I think that I will be surprised at how much I can complete.

This post has no tag

2 comments

Aug 25

Using jnp as a JBoss heartbeat

Categories:

Computers, jboss, jruby

by Matt Williams

jnp is a JBoss protocol which exposes jndi. It is, by default, bound to port 1099. I’d been using that port as a heartbeat, but “cheating” — I would open a socket and then close it immediately. However, this caused problems. jnp is chatty. And it got upset at my not letting it say ‘hi’ before I dropped the connection. So, here’s a code snippet (jruby, the Java should be an exercise for the student) which allows you to actually do an intelligent check.

  def check_port(server)
    @logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port})"
    begin

      env = java.util.Properties.new();
      env.set_property("java.naming.factory.initial",
                       "org.jnp.interfaces.NamingContextFactory");
      env.set_property("java.naming.provider.url",
                       "#{server.host}:#{server.port}");
      ctx = javax.naming.InitialContext.new(env);

      # if the server is not running, we'll get an error here because
      # it will timeout.
      ctx.list("")
      ctx.close
      @logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port}): Succeeded"
    rescue javax.naming.CommunicationException => comm_error
      @logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port}): Not Running"
      begin
        ctx.close
      rescue Exception => ignore_me
      end
      return false

    rescue Exception => e2
      @logger.info "check_port: #{server.fqdn}(#{server.host}:#{server.port}): FAILED: #{e2.to_s}"
      return false
    end
    return true
  end

def check_port(server)

@logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port})"

begin

env = java.util.Properties.new();

env.set_property("java.naming.factory.initial",

"org.jnp.interfaces.NamingContextFactory");

env.set_property("java.naming.provider.url",

"#{server.host}:#{server.port}");

ctx = javax.naming.InitialContext.new(env);

# if the server is not running, we'll get an error here because

# it will timeout.

ctx.list("")

ctx.close

@logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port}): Succeeded"

rescue javax.naming.CommunicationException => comm_error

@logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port}): Not Running"

begin

ctx.close

rescue Exception => ignore_me

end

return false

rescue Exception => e2

@logger.info "check_port: #{server.fqdn}(#{server.host}:#{server.port}): FAILED: #{e2.to_s}"

return false

end

return true

end

Tags: Java, Java Naming and Directory Interface, JBoss application server, jruby

Leave comment

Jul 30

z-index and events

Categories:

Uncategorized

by Matt Williams

Today’s lesson has to do with z-index and events. I’d had a png with transparant portions that I wanted to use as a mask, so that information from underneath would not show. However, buttons, links, and hovers were not working — the top level element was taking the events and eating them. A change of z-index and they started behaving as expected.

Tags: html css z-index gotchas

1 comment

Jul 29

JBoss port confusion

Categories:

gotchas, jboss

by Matt Williams

We ran into a case where JBoss was unable to come up; it gave the following (partial) exception:

java.rmi.server.ExportException: Port already in use: 1098; nested exception is:
java.net.BindException: Cannot assign requested address

After poking around with netstat and lsof, we couldn’t find anything that was binding to the port. I’d made the assumption that it was bound, totally missing the next line. As it turns out, we were attempting to bind to a vip which, although it existed in DNS, was not defined on the host on which the error occurred. The “cannot assign requested address” was the clue.

Tags: dns, gotchas, Java, jboss

Leave comment

May 14

SSL Joys

Categories:

gotchas, howto, tips

by Matt Williams

The nice thing about standards is that there are so many of them to choose from. Andrew S. Tanenbaum

I’ve been working with a Apache proxy to force SSL and https. Well, I haven’t had any control over the certificates. And they can come in so many versions, especially given that Microsoft wants to do things its own way and the Apache web server instance is sitting on a windows virtual instance.

I’ve gotten the private key in two different formats, .pfx and .pvk.

.pfx can be converted to the pem file format which Apache is expecting via the following:

openssl pkcs12 -nodes -in infile.pfx -out out.pem

You then need to edit it, stripping out everything but the private key. Once that’s accomplished you’re good to go.

.pvk, however, isn’t supported in openssl until version 1.0. Joy!

Tags: Apache, private keys, Public key certificate, SSL, Transport Layer Security

Leave comment

Apr 10

After long silence

Categories:

Uncategorized

by Matt Williams

The hiatus has been due to me having been really sick with a weird neurological disorder. I didn’t do any coding at all for over 2 months. I’m starting to feel better, but I still have my good days and bad. So, there will be updates. Hopefully before not too much longer.

This post has no tag

Leave comment

Feb 13

New Ruby Blog

Categories:

administrivia

by Matt Williams

I’ve started a new ruby blog. Whereas this one tends to longer posts (and not just ruby), the other is intended for short, tight pieces which focus on a single idea. In general they will be in the format of “mini sagas“. I’m shooting for daily updates on it.

Ruby Blender

Tags: administrivia, mini sagas, ruby

Leave comment

Feb 11

Javascript with CSS Sprites Animation

Categories:

css, javascript, Uncategorized, web, web design

by Matt Williams

One of the issues with gif animations is being able to stop and start them at will. This post examines a method of using javascript to control CSS Sprites for Animation.

We’re going to show how one can create the following animation using javascript and sprites and what benefits you might receive:

Animated Gif

The gist of this method is to use css background images, which are swapped out via javascript to show and control the animation. In a filesize test using an animation with 9 frames, the sprites actually require less memory than a comparable animated gif:

File	Size	Description
Individual frames as separate PNG’s	95421	Baseline — this is the sum of the sizes of the 9 frame files.
anim.gif	43463	Animated gif version
knot.png	81701	24 bit PNG, sprites. Notice that this is smaller than the sum of the 9 files, but quite larger than the animated gif.
knot-grey.png	49708	Greyscale version of the png sprites. This is much smaller and approaches the size of the gif animation.
knot.gif	40853	Gif version of the sprites. This is smaller than the anmated version.
knot-idx.png	38281	Indexed version of the png sprites. Smallest yet.

I think that between the added control, decreased number of files to download (a single file containing sprites can be used in many places), and the potential for reduced file size, that this is a viable method for producing animations.

The javascript code is library agnostic. Had I tied it to one library or another, I could have made it shorter, but I think that the benefits of being agnostic outweigh the potential byte savings.

// Except as otherwise noted, the following code is copyright 2008, 2009
// by Matthew Williams
//
// Usage and description of the script may be found at:
// http://matthewkwilliams.com/
//
// In order to use it, you need the following:
// + A sprite file
// + CSS entries for the locations of the sprites.
//   These are named FOO-frame-n where foo is the name of the animation,
//   and n is the frame.
// + A block entity in which the animation will be placed.
//   This entity needs the following css rules since we're using the css
//   background trick:
//   + width
//   + height
//
// + A sample use would be as follows:
//   <script src="sprite-animator.js" type="text/javascript"><!--mce:0--></script>
//

//   <script type="text/javascript"><!--mce:1--></script>
//   <button onclick="gearanim.start(); return false;">Start</button>

//   <button onclick="gearanim.stop(); return false;">Stop</button>

// This object does the updating of the sprite animation
function SpriteUpdater(instance)
{
   var obj = instance;
   this.updateSprite = function()
   {
      var elem = document.getElementById(obj.id + '-sprite-container');
      var a = elem.className.split('-');
      var num = parseInt(a[a.length - 1]);
      var newNum = num;
      if (num >= obj.numFrames) {
         newNum = obj.loop ? 1 : obj.numFrames;
      } else {
         newNum = newNum + 1;
      }
      if(newNum != num)
         elem.className = obj.id + '-frame-' + newNum;
      else
         clearInterval(obj.intervalID);
   };

}

// This object handles the animation
// + id = the id of the block
// + file = the file which contains the sprites
// + loop = true/false whether it loops or not
// + delay = what is the delay between frames?
function SpriteAnimator(id, file, loop, delay) {

   // this function and the next are from css-toolbox.js
   // created by Patrick Hunlock :: http://www.hunlock.com
   // and originally found at the JavaScript Source:
   // http://javascript.internet.com
   function getCSSRule(ruleName, deleteFlag) {
      if (document.styleSheets) {
         for (var i=0; i

';
      element.innerHTML = insertion + element.innerHTML;
   };

   // add css rules for the sprite container
   this.updateCSS = function()
   {
      var rule = addCSSRule('#' + this.id + '-sprite-container');
      rule.style.backgroundImage = 'url("' + file + '")';
      rule.style.backgroundRepeat = 'none';
      rule.style.padding = '0';
      rule.style.margin = '0';
      rule.style.width = '100%';
      rule.style.height = '100%';
   };

   // stop the animation
   this.stop = function() {
      if (this.intervalID != false)
      {
         clearInterval(this.intervalID);
      }
   };

   // start the animation
   this.start = function(){
      updater = new SpriteUpdater(this);
      this.intervalID = setInterval(updater.updateSprite,this.delay);
   };

   this.id = id;
   this.file = file;
   this.loop = loop;
   this.delay = delay;
   this.updateHTML();
   this.updateCSS();
   this.numFrames = this.countFrames();
   this.intervalID = false;
}

100

101

102

103

// by Matthew Williams

// Usage and description of the script may be found at:

// http://matthewkwilliams.com/

// In order to use it, you need the following:

// + A sprite file

// + CSS entries for the locations of the sprites.

// These are named FOO-frame-n where foo is the name of the animation,

// and n is the frame.

// + A block entity in which the animation will be placed.

// This entity needs the following css rules since we're using the css

// background trick:

// + width

// + height

// + A sample use would be as follows:

// <script src="sprite-animator.js" type="text/javascript"></script>

// <script type="text/javascript"></script>

// <button onclick="gearanim.start(); return false;">Start</button>

// <button onclick="gearanim.stop(); return false;">Stop</button>

// This object does the updating of the sprite animation

function SpriteUpdater(instance)

{

var obj = instance;

this.updateSprite = function()

{

var elem = document.getElementById(obj.id + '-sprite-container');

var a = elem.className.split('-');

var num = parseInt(a[a.length - 1]);

var newNum = num;

if (num >= obj.numFrames) {

newNum = obj.loop ? 1 : obj.numFrames;

} else {

newNum = newNum + 1;

}

if(newNum != num)

elem.className = obj.id + '-frame-' + newNum;

else

clearInterval(obj.intervalID);

};

}

// This object handles the animation

// + id = the id of the block

// + file = the file which contains the sprites

// + loop = true/false whether it loops or not

// + delay = what is the delay between frames?

function SpriteAnimator(id, file, loop, delay) {

// this function and the next are from css-toolbox.js

// created by Patrick Hunlock :: http://www.hunlock.com

// and originally found at the JavaScript Source:

// http://javascript.internet.com

function getCSSRule(ruleName, deleteFlag) {

if (document.styleSheets) {

for (var i=0; i

element.innerHTML = insertion + element.innerHTML;

};

// add css rules for the sprite container

this.updateCSS = function()

{

var rule = addCSSRule('#' + this.id + '-sprite-container');

rule.style.backgroundImage = 'url("' + file + '")';

rule.style.backgroundRepeat = 'none';

rule.style.padding = '0';

rule.style.margin = '0';

rule.style.width = '100%';

rule.style.height = '100%';

};

// stop the animation

this.stop = function() {

if (this.intervalID != false)

{

clearInterval(this.intervalID);

}

};

// start the animation

this.start = function(){

updater = new SpriteUpdater(this);

this.intervalID = setInterval(updater.updateSprite,this.delay);

};

this.id = id;

this.file = file;

this.loop = loop;

this.delay = delay;

this.updateHTML();

this.updateCSS();

this.numFrames = this.countFrames();

this.intervalID = false;

}

Sample CSS looks like this:

.knot-frame-1{background-position: 0px 0px;}
.knot-frame-2{background-position: -138px 0px;}
.knot-frame-3{background-position: -276px 0px;}
.knot-frame-4{background-position: -414px 0px;}
.knot-frame-5{background-position: -552px 0px;}
.knot-frame-6{background-position: -690px 0px;}
.knot-frame-7{background-position: -828px 0px;}
.knot-frame-8{background-position: -966px 0px;}
.knot-frame-9{background-position: -1104px 0px;}

.knot-frame-1{background-position: 0px 0px;}

.knot-frame-2{background-position: -138px 0px;}

.knot-frame-3{background-position: -276px 0px;}

.knot-frame-4{background-position: -414px 0px;}

.knot-frame-5{background-position: -552px 0px;}

.knot-frame-6{background-position: -690px 0px;}

.knot-frame-7{background-position: -828px 0px;}

.knot-frame-8{background-position: -966px 0px;}

.knot-frame-9{background-position: -1104px 0px;}

Here’s the javascript source file:
sprite-animator

Tags: css, javascript, sprites

3 comments

Feb 06

Chibi gets an upgrade

Categories:

Uncategorized

by Matt Williams

I’m going to have to send my “big” laptop off for servicing, so I upgraded chibi, or as my daughter calls it, “Baby yaptop”. I upgraded the ram to 2gb — it was only $27 with tax. I had held off on this because I didn’t want to “void the warranty”. I found out today that increasing the ram wouldn’t do so, which was good because I was going to do it anyway. I also replaced the 2gb sd card with an 8gb one. I’d recently put eeebuntu on it — I’ve really been enjoying it.

However, since I added the extra ram, it’s running a *lot* faster. I’m thinking that Linux is doing a lot less behind the scenes in terms of juggling memory & is able to cache a lot better than it had. Things that might take a second or more previously take almost no time at all.

I should have done this a long time ago.

The end result is that I’ve got a very usable system now, even if it’s “only” got a 900mhz processor.

This post has no tag

Leave comment

Feb 05

Web Based Portable mysql tool suite

Categories:

glassfish, jruby, mysql, php, tools, utilities, web

by Matt Williams

Are you limited in what software you can use at work? This article details how to have a web based tool suite for mysql. It currently has the following tools:

AjaxMyTop — a php implementation of mytop (think top for mysql) which runs in a browser.
rbdb — a phpmyadmin work-alike in progress. It’s the result of the 2008 Rails Rumble contest.

So you’ve noticed that both a php and a ruby application are included. Pretty spiffy, eh?

The magick partly lies in the container — I’m using GlassFish v3 prelude. Another piece is Quercus, a Java implementation of PHP 5. JRuby is used for ruby.
Read the rest of this entry »

Tags: glassfish, jruby, mysql, php, ruby, utilities, web

Leave comment

Ramblings

Musings of Matt Williams

Weaving with Light Pt. 1

Abusing HAProxy: Stupid Simple Easy Dashboards

Rules for Operations

DevOps Creed (Work in Progress)

I am not a Mindreader: a mini-saga

Quick thought on programming and distractions

A wise man, recognizing that the internet is but an illusion, does not act as if it is real, so he escapes the suffering.

There are more things in heaven and earth, Horatio, than are dreamt of in your internet….

Using jnp as a JBoss heartbeat

z-index and events

JBoss port confusion

SSL Joys

After long silence

New Ruby Blog

Javascript with CSS Sprites Animation

Chibi gets an upgrade

Web Based Portable mysql tool suite

Subscribe to Blog via Email

Recent Posts

Top Posts & Pages

Archives

Categories

Copyright