Monday, June 21, 2010

Uberconf Impressions, Day 1

Last week a group of us from eCollege attended the Uberconf presentation here in the Denver area.  I figured I'd post a few impressions:

First off - the venue - the Westin in Westminster, CO.  Nice place.  Really awesome food whether you are a vegetarian or a carnivore.  Free drinks all day.  Decent coffee, although the cups were oddly small.  One note to the Westin - people operate better at temperatures higher than 58 degrees.  It was FREAKING COLD in there.

Now on the conference organization.  This was one of the best flows of any conference I've attended.  There weren't too many people working the conference, and it still went well.  Easy registration process, good marketing materials (4GB USB stick - not bad), and two t-shirts I would be super embarrassed about wearing.  Easy to figure out what sessions were coming up and where they were going to be.  One minor nit - it's a developer conference, which means laptops - next time, get more power strips in the rooms, at least for the workshops.

And, finally the important stuff - the sessions (day 1):

Patterns of Modular Architecture - This was not quite what I had hoped.  I was looking for patterns, and instead got a fairly basic explanation of how to make your dependencies fairly one-way and isolated.  Neat I guess?  A decent refresher, but definitely nothing earth-shattering, and the most interesting part was OSGI, which the presenter covered for literally two minutes at the end of the presentation.  It did look promising, though.

Common Antipatterns and how to Avoid Them - This was well presented, but it was still a little light.  Good reminders on some common sense things NOT to do, and some reasonably interesting stuff out there - that this presentation was really hitting home with some of the attendees scared me - some of these were things that just shouldn't be happening now, and they obviously still are!

Architect for Scale - This was a good session - lots of 'things you should be doing when you get to this size/load'.  There were a fair amount of good notes about what was not enough, what was too much, and how to move up without huge disruptions

Automated Deployment with Maven - This was a huge win.  It was a discussion about how to use Maven plugins to streamline and automate the numerous steps that go into releasing a module of code.  With maven, it involves updating poms, branching, integrating, labeling, etc, and many manual steps.  With some of the tips in the presentation, I was able to make a releasable unit this morning in about 10 minutes with the help of some maven doc.  Why were we not doing this!?!?  Oh well - awesome.  Worth the price of the registration itself.

Architecture - Non-functional Requirements - This was more of a 'what goes into architecture' talk, than something specifically about non-functionals, but very interesting nonetheless.  As someone who is headed down that path, it validated much of what I think architecture is about.  There was some great back and forth in this presentation from the presenter of this session and the presenter of the earlier Antipattern session.

Tuesday, June 1, 2010

Grails Wizardry: Mocking all your web services with Grails


At work, we are using EC2 to run capacity tests on our environment, which would normally be pretty trivial, but we are a big SAAS shop with tons and tons of endpoints internally.  Without setting up EVERYTHING in the cloud, we can't really run our tests...or can we?  We would love to use Amazon VPC for EC2, but it requires a fair amount of intervention from your network team.  That will be a great alternative down the road - being able to point back into the internal network to access machines rather than deploying them in the cloud.  So, plan b - Using grails, I was able to mock every single .NET service that our application talks to in about three hours.  Here are the details:

We use SOAP services that return some XML, I simply used Fiddler to see what responses are sent back over the wire for each service, and I was ready to rock.  There are two main pieces to the puzzle:


Generating XML is almost too easy in Groovy.  Using the instructions here, I was able to write some code that spits out some xml based on info passed in.  For instance this sample Grails controller will take a login and company and return an XML document with a user id and company id:

import groovy.xml.MarkupBuilder

class UserController {

  * /MyService/users/getuser?login=myuser&company=mycompany
  def returnUser = {

        def user = params.login
        def comp =

        def writer = new StringWriter()
        def xml = getXMLBuilder( writer )

        xml.'user'('xmlns:xsi': getNsXsi(), 'xmlns:xsd': getXsd(), 'xmlns': getXmlNs() ) {
          userId( "${comp }@${user}" )
          compId( "${comp}@compId" )

        render( text: writer.toString(), contentType:"text/xml", encoding:"UTF-8" )

  def getXMLBuilder( StringWriter writer ) {

        writer.append(  "" )

        return new MarkupBuilder( writer )

  def getNsXsi() {
        return ""

  def getXsd() {
        return ""

  def getXmlNs() {
        return ""

Now that you have defined your controller, you need to make it so your application can make its normal request to the url it has configured but still get to your controller.  That's where the URLMappings.groovy class comes in:


The UrlMappings file already exists by default when creating a project.  This file is built to map external urls to your controllers - you can use it to create nice shiny RESTful URLs, or just to do some utilitarian mappings for backwards compatibility, etc.  Obviously not every project's requirements map to the grails conventions on how urls map to controllers.  To add access to your controller from a different url, you just need to add the following snippet - this will allow Grails to map your request from something like




    "/MyService/users/getuser" {
          controller = "user"
          action = "returnUser"

More information can be found at this link.

At this point, you have a service running that will return the valid XML for your service, and will respond to a call at a URL that doesn't actually match.  Now you can rinse and repeat for each service that you need to mock out.  Happy Grailing!