Category Archives: Fixin’s

Resolving Git via ssh asking for password on Windows (valid key, Gitolite repo)

Posted on by
2

Sigh, I just spent several hours poking myself in the eye with a stick over a Git client issue.

I have a Win7 system (Dell, of course) with TortoiseSVN, PuTTY, and GIT all happily configured.  I’ve been using Github via HTTP without any issues.

We recently spun up Gitolite to maintain a local clone of our public repos.  For this inside-the-firewall repo, we are only allowing SSH connections.   The SSH key bits are well documented; however, I encountered an error that did not surrender to Google.

I was able to verify my key using SSH “ssh -T gitolite@[host]” with a return that included all the available repos.  That showed me that my public key was correctly registered and my private key was correctly stashed.

HOWEVER, When I run “git clone gitolite@[host]:crowbar” I would get prompted for a password for gitolite.

The resolution turned out to be simple: Git could not use the TortoiseSVN Plink!

When I inspected the environment variable GIT_SSH, it gave me the path for plink.exe.

I removed the GIT_SSH setting (using “set GIT_SSH=”) and that immediately resolved the issue.

OpenStack Swift Demo (in a browser)

Posted on by
2

I’m working on mini-demo project for OpenStack Swift.  To keep things very simple and easy to understand, I decided that the whole demo would work in JavaScript in the browser.  I also choose to use RackSpace’s CloudFiles as a Swift target for testing since they have the same API are are universally available (unlike my lab systems).

One advantage of this approach is that FireBug makes it very nice to debug and check the activity of the code.  Unfortunately, FireBug also seems to eat the headers that I need.  *Let me phrase that in a google friend way so that someone else will not loose the 2 hours I just lost*

“XmlHttpRequest setRequestHeader FireFox Not Respected when using FireBug”

It works great in Safari. So onward and upward.  So far, I’ve got step #1 ready – getting the authorization token back from the cloud site.

Here’s the HTML page (you need jQuery too).  Basically, it uses the username and key from the inputs to set “x-auth-user” and “x-auth-key” header attributes.  These attributes will allow Swift to return a token that you can use on future requests when you want to do useful work.

<!DOCTYPE html>

<html>

<head>

<title>Dell Swift Demo [0.0]</title>

<script src=”jquery.js” type=”text/javascript”></script>

<script type=”text/javascript” charset=”utf-8″>

var xmlhttp = null;

function swiftLogin() {

var usr = $(‘input:text[name=usr]’).val();

var key = $(‘input:text[name=key]’).val();

// code for IE7+, Firefox, Chrome, Opera, Safari (UR SOL IE<7)

xmlhttp = new XMLHttpRequest();

xmlhttp.onreadystatechange=function() //callback

{

if (xmlhttp.readyState==2)

{

$(‘#status’).replaceWith(xmlhttp.getResponseHeader(“X-Auth-Token”));

}

}

xmlhttp.open(‘GET’,’https://auth.api.rackspacecloud.com/v1.0&#8242;, true);

xmlhttp.setRequestHeader(‘Host’, ‘auth.api.rackspacecloud.com’);

xmlhttp.setRequestHeader(‘X-Auth-User’, usr);

xmlhttp.setRequestHeader(‘X-Auth-Key’, key);

xmlhttp.send();

}

</script>

</head>

<body>

<div id=”credentials”>

<fieldset id=”credentials” class=””>

<legend>Swift Login</legend>

<label for=”user”>User: </label><input type=”text” name=”usr” value=”user” id=”user”>

<label for=”key”>Key: </label><input type=”text” name=”key” value=”key” id=”key”>

<input type=”button” name=”Login” value=”login” id=”Login” onclick=”swiftLogin();”>

</fieldset>

</div>

<div id=”status”>[pending]</div>

<div id=”footer”>Time?</div>

<script type=”text/javascript”>

$(‘#footer’).replaceWith((new Date).toString());

swiftLogin();

</script>

</body>

</html>

Time vs. Materials: $1,000 printer power button

Posted on by
Reply

Or why I teach my kids to solder

I just spent four hours doing tech support over a $0.01 part on an $80 inkjet printer.  According to my wife, those hours were a drop in the budget in a long line of comrades-in-geekdom who had been trying to get her office printer printing.  All told, at least $1,000 worth of expert’s time was invested.

It really troubles me when the ratio of purchase cost to support cost exceeds 10x for a brand new device.

In this case, a stuck power button cover forced the printer into a cryptic QA test mode.  It was obvious that the button was stuck, but not so obvious that that effectively crippled the printer.   Ultimately, my 14 year old striped the printer down, removed the $0.01 button cover, accidentally stripped a cable, soldered it back together, and finally repaired the printer.

From a cost perspective, my wife’s office would have been exponentially smarter to dump the whole thing in to the trash and get a new one.   Even the effort of returning it to the store was hardly worth the time lost dealing with the return.

This thinking really, really troubles me.

I have to wonder what it would cost our industry to create products that were field maintainable, easier to troubleshoot, and less likely to fail.  The automotive industry seems to be ahead of us in some respects.  They create products that a reliable, field maintainable, and conform to standards (given Toyota’s recent woes, do I need to reconsider this statement?).  Unfortunately, they are slow to innovate and have become highly constrained by legislative oversight.  Remember the old “If Microsoft made cars” joke?

For the high tech industry, I see systemic challenges driven by a number of market pressures:

  1. Pace of innovation: our use of silicon is just graduating from crawling to baby steps.  Products from the 90s look like stone tablets compared to 10’s offerings.   This is not just lipstick, these innovations disrupt design processes making it expensive to maintain legacy systems.
  2. Time to market: global competitive pressures to penetrate new markets give new customer acquisition design precedence.
  3. Lack of standards: standards can’t keep up with innovation and market pressures.  We’re growing to accept the consensus model for ad hoc standardization.  Personally, I like this approach, but we’re still learning how to keep it fair.
  4. System complexity: To make systems feature rich and cost effective, we make them tightly coupled.  This is great at design time, but eliminates maintainability because it’s impossible to isolate and replace individual components.
  5. Unequal wealth and labor rates:  Our good fortune and high standard of living make it impractical for us to spend time repairing or upgrading.  We save this labor by buying new products made in places where labor is cheap.  These cheap goods often lack quality and the cycle repeats.
  6. Inventory costs: Carrying low-demand, non-standard goods in inventory is expensive.   I can a printer with thousands of resistors soldered onto a board for $89 while buying the same resistors alone would cost more than the whole printer.  Can anyone afford to keep the parts needed for maintenance in stock?
  7. Disposable resources: We deplete limited resources as if they were unlimited.  Not even going to start on this rant…

Looking at these pressures makes the challenge appear overwhelming, but we need to find a way out of this trap.

That sounds like the subject for a future post!

WhatTheBus fun with Cucumber and MemCacheD

Posted on by
Reply

Sometimes a problem has to kick you upside the head so you can learn an important lesson.  Tonight’s head slapper was an interaction between Cucumber and MemCacheD.

If you are using CUCUMBER AND MEMCACHE read this post carefully so you don’t get burned.  If you’re using MemCache and not writing tests then return to Jail, do not collect $200.

It’s important to note that Cucumber has the handy side effect of running each scenario in a transaction.  The impact is that the data from each scenario does not impact the next scenario.  (note: you can pre-load data into cucumber using fixtures).

However, Cucumber does not do any rollback for Cache keys added into MemCache.  In fact, your MemCache entries will happily persist between your development and test systems.

WhatTheBus has a simple check to reduce database writes – it only writes to the database if there is no cache hit for the bus.  My thinking is that we only need to add a new bus if there is no key as shown in this partial snippet:

  cache = Rails.cache.read params[:id]
  if cache.nil?
     bus = Bus.find_or_create_by_xref :name => params[:name], :xref => params[:id]
  end

This works great for live testing, but fails in technicolor for Cucumber because tests with the same ID will not make it to the find_or_create.

To solve the problem, I had to add a pre-condition (‘given’ in Cucumber speak) to each scenario to make sure the cache was cleared.  It looks like this in the scenario feature:

  Given no cache for "1234"

And that’s translated as code in the steps like so:

  Given /^no cache for "([^\"]*)"$/ do |id|
   Rails.cache.delete id
  end

Recovering Outlook Autocomplete, just in the NK2 of time

Posted on by
Reply

I manged to head off a reverse upgrade today by renaming a file.  A couple of days ago, Microsoft Outlook 2007 ate my wife’s email configuration.  The error message was a “Unable to open the Outlook Window” and Microsoft’s support article led me to remove the registry key that linked her email configuration to her email data!

I bet you still can hear echos of her molars grinding.

I had to start from a blank configuration.  Luckily, I was able to find and put back her email and archive PST files.  Birds were singing and dust motes scintillated in the morning sun.

Unfortunately, my work was not done.  The file (user.nk2) that Outlook uses to cache email addresses for its autocomplete feature had been set to an empty file!  Major travesty, like most Outlook users, this file was my wife’s primary contact list.   She would rather abandon her frilly “artist” laptop for her ancient desktop just to recover use of that file!

Luckily, Outook did not stomp on the earlier version of the NK2 file.  I closed Outlook, found the two NK2 files in C:\Users\Wife\AppData\Local\Microsoft\Outlook, and swapped the old file for the new file.  Of course, I also made a BACKUP of the beloved NK2 file.  When I re-opened Outlook, the cache recovered.

Moral: go backup your NK2 file right away.  Apparently, Outlook 2007 is known to corrupt its configuration regularly!

Useful link about autocomplete on TimeAtlas.