When to delete an abandoned project?

One of the projects I worked on was funded by the EU and so the code needed to be open-sourced. We did this by placing the code on SourceForge. And that was mostly all that was done. Eventually the EU stopped funding the project and so now the code sits abandoned. Untended. Crumbling with each new release of a dependent toolkit or tool.

When it was coded it represented some of my best work. Some of it is still good. Some of it I look upon with horror. This posting is not about me and my code but about the code's life. I can say without any doubt that the code will never be used again. Even in part. Anything that was useful has already been subsumed into other projects. So why keep it? Why should SourceForge pay to keep it available? I don't have a good answer yet, but I am leaning towards deleting it.

A less violent killmatching

After reading my previous posting Jonathan Stockdill suggested that the command really needed dry-run and/or confirmation flags. He is right.

A challenge in doing this in bash was in coordinating the input from the ps pipeline and the user's confirmation. I came up with an answer but am not sure it is the right one and so have asked on Stackoverflow.com for help. Until then, here is a less violent killmatching:

#!/bin/bash -e

PS_OPTS=${PS_OPTS:- -A -o pid,command}

INTERACIVE=false
DRY_RUN=false

while [ 0 -ne $(expr $1 : '\-') ]
do
  case "$1" in
    -i) INTERACIVE=true ;;
    -n) DRY_RUN=true ;;
    -h) echo "usage: killmatching [-in] [kill-options] pattern1 pattern2 ... patternN" ; exit ;;
    *) KILL_OPTS="$KILL_OPTS $1" ;;
  esac
  shift 1
done

exec 4<&0

for PATTERN in "$@"
do
  ps $PS_OPTS \
    | grep -v -F grep \
    | grep -v -F "$0" \
    | grep -e "$PATTERN" \
    | while read PID COMMAND
  do
    if $INTERACIVE
    then
      read -u 4 -p "kill $PID $COMMAND? (y/N) " choice
      if [ "$choice" == "Y" -o "$choice" == "y" ]
      then
        kill $KILL_OPTS $PID
      fi
    elif $DRY_RUN
    then
      echo kill $KILL_OPTS $PID
    else
      kill $KILL_OPTS $PID
    fi
  done
done

# END

Killmatching: a violent killall.

I always seem to need a better killall especially when running script or Java processes where the command name is, for example, "java". Scratching the itch, here is killmatching

#!/bin/bash -e

# usage: killmatching [ kill-options] pattern1 pattern2 ... patternN

PS_OPTS=${PS_OPTS:- -A -o pid,command}

while [ 0 -ne $(expr $1 : '\-') ]
do
  KILL_OPTS="$KILL_OPTS $1"
  shift 1
done

for pattern in "$@"
do
  for pid in $(ps $PS_OPTS \
    | grep -v -F grep \
    | grep -v -F "$0" \
    | grep -e "$pattern" \
    | awk '{ print $1 }')
  do
    kill $KILL_OPTS $pid
  done
done

Be very careful using it with one wrong pattern and you can shutdown the computer.

Some ps commands do not support the -A and -o options. Edit these options for your ps.

Establishing a new leader and informing the lead

I have a distributed system design problem. The problem brief is

We have many clients to a service. The service needs to be fault-tolerant and so it will have many replicas. When a client can no longer access the service it will switch to a replica and inform all the other clients will switch to the same replica. (It is not acceptable to load-balance across the replicas as the replicas' data values are not exactly the same but all the clients must return the same data values at all times.)

My current design is to have the client, on failing to reach the service, ask for a new service leader. When a new service leader is established it will then notify all the clients to use it.

As with many distributed coordination designs I need a distributed group manager. I am considering the use of JGroups and/or Apache Zookeeper in a solution.

Is there an existing recipe or recipes that I should be looking at to solve this problem?

Update: We finally decided to have a master make a new copy of the repository, copy it to all service hosts, and notify the service hosts to switch to the new repository. The master tracks who has switched and raises an alarm if there is missing switchers after a fixed interval.

"I like Obamacare."

About a week ago now I was tired of NPR using the term "Obamacare" instead of the laws real name, The Affordable Care Act. And so I sent email and Facebook messages to the local and national NPR offices:

Dear NPR, please call the law by its rightful name, The Affordable Care Act, and not the prejudicial name its opponents want it called.

Both offices wrote back. The local office, RIPR, said that they would use the real name during its initial reference in a story and Obomacare afterwards. Further, "[...] because (like it or not) that's what many people know it by." I was peeved by this sloppiness and the lack of an historical grasp of the significance of names and so sent a rather strident response (for which I did apologize later). The message I receive from NPR's ombudsman was remarkable:

Thank you for your inquiry. We asked Ron Elving about the term and here is his reponse:

Initially, the term was coined and used by opponents of the ACA. It had a sneering kind of tone to it, implying that the president was trying to imitate or piggyback on the popularity of Medicare. (As indeed a lot of commercial products have done since 1965.) The White House initially resisted the term for this reason, preferring Patient Protection and Affordable Care Act.

In the headline wars of the cable tv news world, of course, PPACA never had a chance. Obamacare became increasingly common.

So some while ago, the White House did a turnaround and embraced the term. I am attaching a copy of the memo David Axelrod wrote about the term and why it was okay to use it as far as he was concerned. Axelrod was still in the White House as the top political advisor at the time and is now in Chicago co-directing the re-elect campaign.

From: David Axelrod
Date: Fri, 23 Mar 2012 17:34
To: [Supporters]
ReplyTo: info@barackobama.com
Subject: Hell yeah, I like Obamacare

Friend --

I like Obamacare.

I'm proud of it -- and you should be, too.

Here's why: Because it works.

So if you're with me, say it: "I like Obamacare."

Obamacare means never having to worry about getting sick and running up against a lifetime cap on insurance coverage. It gives parents the comfort of knowing their kids can stay on their insurance until they're 26, and that a "pre-existing condition" like an ear infection will never compromise their child's coverage.

It's about ending the practice of letting insurance companies charge women 50 percent more -- just because they're women.

And Obamacare can save seniors hundreds of dollars a year on prescription drugs -- and gives them access to preventive care that is saving their lives.

President Obama never lost sight of the fact that this reform is about people. People like his own mother, who spent the last years of her life fighting cancer -- and fighting with insurance companies, too.

That shouldn't happen. And because of Obamacare, it can't.

So next time you hear someone railing against Obamacare, remember what they're actually saying they want to take away.

And, today, stand with me in saying, "Hell yeah, I'm for Obamacare":

http://www.facebook.com/l/BAQH_H25mAQF6lqCpWphkfIS3anTqRmAQnppKzyZQcTismg/my.barackobama.com/I-Like-Obamacare

Thanks,

David

P.S. -- Side note: Can you imagine if the opposition called Social Security "Roosevelt Security"? Or if Medicare was "LBJ-Care"? Seriously, have these guys ever heard of the long view?

If President Obama wants to call it Obamacare then I am dropping my opposition and joining those who are reclaiming it as a term for a positive accomplishment of his first term.

Open a new terminal window from the command line with helper script on OSX

With the help of a little script called term you can quickly tail the logs of remote machines each in its own window using

for n in 1 2 3 4 ; do \
term -t ds$n ssh ds$n tail -F ~qs/var1/logs/\?s-common.log ; \
done

The four machines I am watching are called ds1, ds2, ds3, and ds4 and the two log files I am interested in tailing -- qs-common.log and ds-common.log -- are in the same location. Term uses the -t option to set the window's title (if it is not given then the first argument is used.) Don't forget to use ssh-id-copy to configured the remote hosts to use a private key so no password is needed

The term script is

#!/bin/bash
if [ "$1" == "-t" ]
then
  TITLE=$2
  shift 2
else
  TITLE=$1
fi
osascript <<EOH
  tell app "Terminal" 
    set currentTab to do script "printf \\"\\\\e]0;$TITLE\\\\a\\""
    do script "$@" in currentTab
  end tell
EOH

A kanban for one

I know that a visual workplace works to improve productivity. What I did not think about was that it can work for the individual just as well as for the team. During the weekend's browsing I came across this posting about Kanban for One. And, better, the inspiring photograph of Nomad8's office with a kanban board at most desks.

Thus inspired, I created my own Kanban board and used it right from the start of the day. And it worked! It was much easier to manage the set of activities over the day. It was delightful seeing the steady accumulation of "done" tasks. It was also surprising how quickly tasks got stuck. (And it is the stuck tasks that tend to get forgotten.) I plan to keep using the system and see how it goes.

The board is a 1'×2' piece of foam core board from a discarded marketing sign, the markings are with white pencil, and the tasks are written on 2"×1.5" Post It notes. It really couldn't be simpler to construct.

Note that I am using the kanban board in conjunction with an existing bug tracking system. The backlog is managed by the bug tracker. The queue needs to be on the kanban board, however.

Less opportunity to see how much hard work is necessary

Comment on Ian Schreiber's blog post Dreamers:

There seems to be less and less opportunity to see how much hard work is necessary to achieve proficiency and (sometimes) success. The actions of a craftsman in wood, for example, can be seen by sitting at the side of a bench and being attentive. What works and what does not is equally visible. And if the craftsman has a the habit of talking to the work some of his interior worries and choices are available.

My children have no visibility into my work. I am a software programmer. I have been at this trade for 30 years but what can be seen of my efforts and the growth? There is nothing.

From my children's perspective there is no history there is only now and the future. No wonder they and the kids you write of think they can be famous. It requires so little effort.

Sending Growls from a remote host

There are times when I want a notification about the status of a long running process I have running on a remote system. I could have it send an email. I could have it send an instant message. I decided that, since I have a Mac, I would have it send a Growl notification. Growl's GNTP makes this easy and the language bindings available make it easier still.

The one obstacle I had was getting the IP address of the connecting host (i.e., my Mac). Commands like finger and who often show this data but I did not want to scrape the command output as it is different between operating systems. Digging into the code for who at koders.com I discovered that it used the user accounting database utmpx API for getting this data. And so, with all the parts needed, I coded up growler

#!/usr/bin/perl -w

use strict;
use Getopt::Long;
use Growl::GNTP;
use User::Utmp qw(:constants :utmpx);

sub getRemoteHost() {
  my @utmp = 
    sort { $b->{ut_time} <=> $a->{ut_time} } # reverse sort by time
    grep { $_->{ut_user} eq getlogin() } # filter by current user
    getutx(); # get user accounting data
  ( my $host = $utmp[0]->{ut_host} ) =~ s/:.*$//;
  return $host;
}

my $title = "";
my $host = getRemoteHost();
my $port = 23053;

GetOptions( 
  'title|t=s' => \$title, 
  'host|h=s' => \$host,
  'port|p=i' => \$port ) 
  or do {
    print STDERR "usage: $0 ",
      " [ --title text ]",
      " [ --host name/ip ]",
      " [ --port number ]",
      " message\n";
    exit(1);
  };
  
my $growl = Growl::GNTP->new(
  AppName => "growler", 
  PeerHost => $host, 
  PeerPort => $port 
);

$growl->register([ { Name => "growler" } ]);

$growl->notify(
  Event => "growler",
  Title => $title,
  Message => join( ' ', @ARGV )
);

# END

My original installation of Growl was broken. This caused all manner of errors during testing. To finally get growler to work I had to uninstall Growl and then install Growl 1.4.

Refactoring Java classes with explicit serialVersionUIDs

I had a small problem today where I needed to refactor a Java class and maintain its serialization identity. I guessed that if I maintained the class's instance variable order and explicitly defined the serialVersionUID class variable with the class's previous implicit value I would be safe. So, before refactoring, I used Java's serialver to get the class's serialVersionUID. I then refactored the class and added the serialVersionUID class variable. But it didn't work. What was wrong? I needed to look into the object's serialization.

An object's serialized form is defined in Java Object Serialization Specification. I really didn't want to read the specification: All that I really wanted was to see the differences between the class's pre-refactor stream and the post-refactor stream. So I used jdeserialize to dump the protocol encoding of the streams.

What was quickly apparent in the dump was that the order of the instance variables within the stream have no relation to their order in the class definition. I was not expecting this. During the refactoring I had renamed some instance variables to better reflect their purpose. Once I reverted the instance variable's names to their previous values the serialization was the same. Success.

A distressing aspect of this exploration was that two objects with the same serialVersionUID will be considered the same by the serialization implementation and so it will misinterpret the bytes in the stream for the bytes needed by the class. The end result is that you get an object that is initialized wrong. I would have expected an exception that indicated the mismatch between data in the stream and data expected by the class. Perhaps there is a command line switch or system property I can use to enforce a stricter pairing. Be very careful when refactoring a class with an explicit serialVersionUID to either remove or update its value before committing the changes.

The trifecta of low-ceremony document management

My comment on How I name files on my Mac:
I too add dates to file names even though I know the creation date is part of the file's meta-data. When files are moved between systems the meta-data is not always preserved. This chance of loss is also what thwart me from using a tagging tool as I can not be assured that the tags will be preserved between systems. And so, the trifecta of low-ceremony document management are

• a good title,
• a date in the title, and
• a good full-text search.

I want more "geek lights"

Geek-lights are the indicator lights embedded on the surface of your electrical equipment. The green "On" light. The blinking light on your ethernet port or USB thumb-drive telling you data is being transferred. Most of them tell you redundant or otherwise obvious facts. I don't need an "on" light for the monitor I am using. It is useful information when in power saving mode, however. Apple seems to have learned this.


However, geek-lights are incredibly useful for other kinds of information. Information that is different for you and me. For example, one to indicate if traffic is too heavy to venture out now. Another to tell me that I have email. Another to tell others that I am in a conference call and not just talking to myself again.

I would like to have a box of these geek-lights that I can use each for a specific purpose. The geek-light would be nothing more than a shallow and wide cylinder with the light on the top, temporary adhesive on the bottom, and the electronics sandwiched in between. Let's call them eyelets as they let you see something ordinarily invisible. Each eyelet is individually addressable by a short range wireless signal. An eyelet receives a signal that indicates whether it is illuminated or not. Eyelets don't send signals back. I can imagine the hardware being something akin to Logitech's Unifying receiver -- that is, unobtrusive.

The question now is, should eyelets have a battery charge indicator light?

"Acting like a startup" is overrated

"Anyone who isn't acting like a startup in publishing [replace with your industry] has a serious problem." I hate this aphorisms. It is not useful and mostly wrong. The only difference between a new product at a startup and one at an established company is where the seed money comes from. Everything else is the same.

A rose by any other name is incorrect: a rant on character sets and encodings

I have been working with XML since SGML. I have been working with character-sets since before cuneiform was contemporary. That is, a long time. I have seen and continue to see characters very poorly handled. Even the use of the term "characters" is wrong. Unicode calls them "code points" as a single character (graphic impression) can be made from one or more code points. Unicode supports both a single code point that represents an e with an acute, U+00E9, and a multiple code point representation, U+0065 with a U+0301. The single code point is 'é' while the multiple code points are 'é'. For most users and most web browsers there is no difference in how this character is presented.
Now é is presented differently in different character-sets and in different character-encodings. For UTF-8 it is represented as two bytes, 0xC3 and 0xA9. For XML it is presented as the numbered entity "é" or "é". For HTML both the XML encodings can be used and the named entity "é" can be used. For percentage encoding within a URL's path and query it is represented as "%C3%A9". Within a domain name that uses punycode it is "xn--9ca". While these differences are not inherently problematic it has been my experience that their combined use very much is.

For example, if I have a URL that contains an é and I want to use this in an HTML A tag's href how do I encode it? All of the following are useable but only the first is correct:

• http://foo.com/bar?%C3%A9
• http://foo.com/bar?é
• http://foo.com/bar?é
• http://foo.com/bar?é

And being correct matters more and more because this stuff is being handled by code. Code is written by programmers and programmers don't universally understand character-encodings and character-sets. Moreover, you have programmers at both ends of the supply chain: The writer writes it wrong and the reader reads it wrong. How many times have you seen the following?

• An HTML named entity being used in XML.
• A entity double encoded, eg é is incorrectly encoded as &é.
• A french text, for instance, with question marks oddly scattered throughout.

I don't have a solution to the misunderstandings and misuses. My only advice is that you have some simple rules and adhere to them:

1. Be clear that you and your supplier know the difference between a character-set and a character-encoding.
2. Don't ever accept bad data. Being generous and accepting (and "correcting") bad data never turns out well for either you or your supplier.
3. Only accept percent character-encoding for URLs.
4. Only accept numbered entities character-encoding for XML & HTML (except for <, >, &, and ").
5. Only accept content for which there is a specified character-set. (For XML it is UTF-8 by default.) So, for HTML form elements make sure to use the accept-charset attribute. For HTTP requests make sure to require the charset attribute of the content-type header. If you can, only accept UTF-8 -- mostly because the supplier's tools will almost aways to the right thing with UTF-8.
6. Never use a character-set in your byte-oriented repositories as anything other than UTF-8. (So, when you get a percent-encoded URL make sure to store it not as supplied but as its decoding.)

I hope this helps.

Need to paint my soldiers.

I have returned to earth after some months of all-things-wargames-all-the-time. I have learned much about Roman, feudal, and 18C and 19C warfare. Perhaps not enough to author a Buffer's Guide but enough to ask respectable initial and followup questions. But what I have not yet done is actually play a game! My Bacuss Saxons and a Vikings are still unpainted. I do not have a game table. I haven't tracked down local DBA wargamers. So over the coming weeks I intended to paint my toy soldier: that is, after helping with kids projects, house projects, garden projects, etc. Wish me luck.

Library catalog, data: URIs, & bookmarklets

My public library, and, I expect, so does your's, uses Innovative Interfaces catalog tools. This web application is the poster child for poor user interface and user experience. It is not my objective to enumerate the problems. Instead, I discovered a useful mechanism of getting around the problem I have with remembering my library card's barcode. (Why on earth do the designers of this software expect me to remember my barcode is unfathomable.)

My original solution was to embed the barcode in a URL that mimicked the web application's form-based login. This URL was then bookmarked to allow for immediate access. This worked for a good number of years until the catalog software was updated. At which point the URL broke and I was unable to reproduce this solution using the updated software. (The obstacle seemed to be the need for a session identification that I could not contrive.) And so I needed a different approach.

The approach I took was to be able to show the barcode when I used the catalog. Having an absolute DIV positioned at the bottom the browser's window is easy to do with CSS. The problem was that to do this I needed to dynamically alter the catalog's HTML. I really did not want to install GreaseMonkey to accomplish this. The next best solution was to have a standalone page with an embedded IFRAME. This give me full control over what was on the page. The HTML is

<html>
    <head>
        <title>South Kingstown Library Catalog</title>
        <style>
            * {
                margin: 0;
                padding: 0;
                border: 0;
            }
            #tab {
                font-family: Verdana;
                position: fixed;
                bottom: 0px;
                right: 4ex;
                padding: 2ex;
                border-top-left-radius: 1ex;
                border-top-right-radius: 1ex;
                color: white;
                background: gray;
            }
        </style>
    </head>
    <body>
        <div id="tab">
        barcode: 123456789
        </div>
        <iframe
            src="https://catalog.oslri.net/search/"
            width="100%"
            height="100%"
            scroll="auto"
            marginheight="0"
            marginwidth="0"></iframe>
    </body>
</html>

I didn't like having to store this page as a file on my local machine and storing it on a HTTP server seemed overkill. Clearly, I was over thinking, but this is what I do for my day job. It then occurred to me that I could encode the page as a data URI and, I hoped, that when I used this URI the browser would render the encoded page. I used David Wilkinson's data: URI creation tool to create the URI. And, to my wonderment, Safari, FireFox, and Chrome (all on OS X) did exactly as hoped for.
What this means is that my future bookmarklets can more sophisticated then I ever considered practical before. Perhaps you can use this discovery too.

Moving forward

One of my favorite lines from M.A.S.H was Frank Bruns insisting that "we must have a plan even if it is wrong." While this was a line intended to ridicule Frank, it has been my experience that creating a plan, even if it turns out wrong, is a positive step forward.

A miniature wargamer begins

I am enamored with all things miniature wargame. Last year I dove into the world of boardgames (and card games) as my sons were now of an age where we could plays games that were enjoyable to each of us. Boardgaming is not, however, a hobby. A hobby requires hands-on creativity. (Aka, dirty hands.) A hobby is what you do between events. While I am up to the challenge of developing boardgames and card games it is too much of an intellectual challenge only and I have enough of that in my day-job. And further, I don't really want to do it.

As a young teenager I had a detailed model Great Western Railway in N gauge. I loved this hobby. It allowed for the creation of a whole world and one run with British timeliness. (Timeliness, is something that has vanished from the modern UK rail system, I am told.) Modeling railways and railroads are still something I look forward to doing again in my dotage, but not now.

What sparked my interest in miniature wargaming come from an unexpected encounter at the Hobby Bunker. This game store is near to my employer's office and so I went to it too look at their stock of boardgames. What I encountered was not, principally, a boardgame store but instead a miniatures wargaming store. As, as it turns out, the Hobby Bunker is one of the best such stores in the US. And so for two hours I wondered the aisles of shelves stocked with unpainted miniatures in plastic and metal of all historical periods; the selection of paints in acrylic and enamel; the shelves of books with the historical accounts of nations, armies, commanders, and battles; wargamer magazines; and wargame rules. (Hobby Bunker does also have a good collection of boardgames.)

That day I only bought an issue of Wargames Illustrated but the next time I bought some plastic saxons and the paint for them. And, like every good wargamer, they remain unpainted in the box still. But that is not because of waning interest but instead I have dove in the deep-end of the pool and am currently surrounded with magazines, military history books, wargaming books (mostly the foundational one), rule books, wargaming podcasts, and, soon to arrive, armies of vikings and saxons in 6mm.

As one of my sons noted, "you are serious about this dad!" I am.

HAVOC

I had a great time Saturday attending the Boston Battle Groups's Havoc Game Convention (HAVOC). My goal in attending was to see different historical periods and different rule sets in play. In the morning I watched Day of Battle rules payed out by Christopher Parker (the rule set's author), his brother, Jen, and Richard Brian. The game is driven by a unique combination of dice (d6) and a standard deck of cards. I need to see the rules played out in a tournament to make a judgement about them. I want to thank Chris and Dick for sharing their time and knowledge with me.

In the afternoon I watched a Punic wars battle played with the the De Bellis Antiquitatis (DBA) rules ((say what). This rule set seems most approachable. It had the feel of a boardgame but played with miniatures on an open table. Since returning from HAVOC I have spent the most time with this rule set. I want to thank Maureen, Spencer, Mike, and Harrison for a wonderful afternoon.

All in all, I met a wonderful group of people at HAVOC. All most willing to ofter advice and help. And Vic Gregoire invited me to join his "The Usual Gang of Idiots" for some wargames later in the year.

Why is Spring taking a perfectly good Set value and passing along a null?

Why is Spring taking a perfectly good Set value and passing along a null to the property's setter? That is, I had a simple bean declared like the following

<bean name="set" class="java.util.HashSet">
  ...
</bean>

<bean name="x" class="...">
   <property name="y">
      <map>
         <entry key="z" value-ref="set"/>
         ...
      </map>
   </property>
</bean>

Where the property's setter is declared

void setY( Map<String,Object> y )

But every time setY() was called the key z's value was null. The problem's answer was very hard to track down. It comes from how Spring automatically converts objects to type specific property values. Spring has two ways of converting a value for use in a property's setter method. The first is based on converting a textual representation to an object via the java.beans.PropertyEditorSupport API. The second is based on Spring's own org.springframework.core.convert.converter.Converter API. I has used a Converter in an unrelated part of my application's Spring context. This was my application's first use of the Converter API. Turning the Converter API on, however, brought with it other conversions I was not expecting. The most detrimental was the Collection to Object converter. When Spring sees that the property expects an Object it tries to convert any value to an Object. (Even though every value is an object.) The Collection to Object converter converts an empty collection to null. Let me say that again .. with emphasis. The Collection to Object converter converts an empty collection to null. My set was empty. And so, a perfectly good empty set value was converted to a null. The correction is the change the setter for property y to

void setY( Map<String,?> y )

And all works now. p.s. I would never have been able to debug this without Spring having open source. Thanks VWware, Spring Source, and all the contributors.