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ALT.NET; London; 13 Sept 2008

Intro

Debate over what ALT.NET is; should it have a set of guiding principles like the Agile manifesto?

Continuous integration & deployment

There seemed to be 3 major areas where people encountered difficulties doing continuous integration & deployment.

 

  1. Configuration files
  2. DB schema migrations
  3. Data migrations.
Best practise approaches discussed were:
Config files
  1. Make sure that  your config files are small. and contain only that config data that changes often (DB connection strings, file paths etc).  Put all your “static” config data into separate files (DI injection config etc).
  2. Consider templated config files; where specific values are injected during deploy process.
  3. Keep all config in simple text files in source control.
DB schema migrations
  1. Migration techniques borrowed from Ruby on Rails – generate change scripts by hand or using tools like SQL Compare; and then apply them using a versioning tool like dbdeploy.
DB data migrations
  1. Take backup before data migration.
  2. Ensure app fails quickly if is a problem; cause if data has changed since deployment then cannot rollback.
  3. Consider apps upgrading themselves and running smoke tests upon startup – and refusing to run if there is a problem – this technique is used by established opensource projects – WordPress, Drupal, Joomla.
Mentioned tools: TFS, Subversion, CC.NET, Jetbrains TeamCity, dbdeploy, SQL compare.
Acceptance testing
It seemed to me that the majority of pain experienced in this area results from a lack of a ubiquitous domain specific language:
  • Build a DSL incrementally during short iterations.  Gives you opportunity to refine, fill in gaps, and train whole team to use same language.
  • Without a DSL, acceptance testing via the UI testing becomes brittle, as you end up specifying your tests at too low a level, (click button A, then check for result in cell B); rather than having a translation from acceptance tests in a higher DSL language to specific UI components.
  • Consider prioritised tests – have a set of facesaving tests / smoke tests that always work, and ensure major things are still working (company phone number correct?  Submit order button still work?).  Acceptance tests can be thrown away if they have served their function of evolving the design / team understanding.
  • The acceptance testing trio – Developers test for success – thus automated testing only tests happy flow – still need exploritory testing by someone with testing mindset; what happens if you do weird stuff?  Tester must have domain knowledge.  Business – what are should happen?  Don’t let developers be forced to make up business rules?
  • Ensure all layers of stack (tests, manuals, code, unit tests) use the same DSL language.
  • How do you get workable acceptance tests – see Requirements Workshops book
  • Short iterations – more focus, incremental specs, opportunity to discuss missing test examples.
  • Key is having a ubiquitous language encoded as a DSL (domain specific language) – develops over time, enables automated accpetance tests, 
  • Sign off against acceptance tests (Green Pepper tool – capture & approve acceptance tests)
  • Talk: The Yawning Gap of ?? doom – infoQ, Martin Fowler
  • Avoid describing these activities as “testing” – people avoid because testing has low social status.
Mentioned tools:  White for Windows GUI testing
Domain driven design
  • Discussion around the difference between DDD; where we treat the concepts & actions as central; vs DB centrered design, where we’re thinking about the data as central, and UI centered design, where the screens are considered central.
  • Concensus was that domain shouldn’t be tightly bound to the DB, or the UI.
  • Ideas around passing DTO objects up to view (UI, webservices etc), andchange  messages bad from view, indicating how the domain should be changed (rather than passing the whole DTO, where you don’t know what has changed).
BDD
  • Defined as Dan North’s Given, When, Then
  • Is it any difference from Acceptance testing? Only that it is better branding, because BDD doesn’t have the word “testing” in it; which prevents people being switched off hearing the word test when discussing specifications.
  • BDD is writing failing acceptance testing first; before writing code.  
  • Unit testing is ensuring that the code is built right, but acceptance testing / BDD ensures that the right code is built.
  • Toolset is still immature.  Fitnesse .NET & Java tooling is most mature toolset.  Many BDD tools (other than Ruby’s rSpec) have been started and abandoned (nBehave, nSpec etc)
  • BDD is not about testing, its about communicating and automating the DSL.  Be wary of implementing BDD in developer tools (e.g, nunit), which prevent other team members (business, customer, testers) from accessing them.
  • Refactoring can break fitnesse tests, because it isn’t part of the code base.
  • Executable specs (via acceptance tests) are the only way to ensure documentation / test suites are up to date & trustable
  • Agile is about surfacing problems early (rather than hiding them until its too late to address them).  So when writing acceptance tests up front is difficult; this is good, because you are raising the communication problems early.
  • The real value is in building a shared understanding via acceptance criteria; rather than building automated regression test suite.
  • Requirements workshops can degenerate into long boring meetings.  To mitigate this problem
Tools:  Ruby Rspec, JBehave, Twist, Green Pepper
Feedback
In the post conference feedback; everyone was overwhelmingly positive; and found the open spaces format very energising.  Fantastic sharing of real world experiences; introductions to new approaches, nuggets of information; great corridor conversations.  Format that allows human interaction.
Next ALT.NET beers on 14th Oct.
Next ALT.NET group therapy in Jan 2009, with larger ventue.

Domain mapping with WordPress MU, Plesk, Apache2 & Ubuntu

Given a WordPress MU install on Plesk running on Ubuntu with Apache2, we want to configure domain mapping so that

user1 can have myblog1.com mapping to their wordpress blog (myblog1.masterwpmu.com) and
user2 can have myblog2.com mapping to their wordpress blog (myblog2.masterwpmu.com)

We need to configure quite a few moving parts:

  1. DNS for masterwpmu.com – this should be an A record, pointing to the IP of your server
  2. DNS for myblog1.com & myblog2.com – these should be CNAME records, pointing to the A record in (1) – eg. masterwpmu.com
  3. Apache2 – we need to alter the apache vhost conf created by Plesk to setup a wildcard alias
  4. WordPressMU – we need to configure it to serve the right content when receiving a request for myblog2.com or myblog2.com

When someone makes a browser request for myblog2.com, the following sequence happens:

  1. myblog2.com is resolved to masterwpmu.com, which is resolved to the IP of your server.
  2. the browser makes a request to the IP, port 80, passing the host header of myblog2.com
  3. Apache intercepts the request to point 80, checks through all its known vhost server aliases, and not finding a match redirects to the wildcard alias pointing to our WPMU install
  4. WPMU gets the request, matches the host header to the correct blog content, and returns the relevant page.

So, how do we configure this?

  1. Create a new Plesk site, with its own domain name (eg. masterwpmu.com) & install WPMU.  Ensure this works.
  2. Create a new CNAME record myblog2.com which resolves to masterwpmu.com (Its also possible to setup an A record pointing to the same IP as masterwpmu.com; although this will break if the IP of masterwpmu.com ever changes).  Google has a nice set of instructions for doing this on most major DNS providers (obviously you’ll want to point to masterwpmu.com rather than ghs.google.com ;) )
  3. Edit the Apache2 vhost conf created by Plesk at: /var/www/vhosts/masterwpmu.com/conf/httpd.include, changing:
    ServerAlias *
    <Directory>
    AllowOverride FileInfo Options
  4. restart Apache2 ( /etc/init.d/apache2 restart)
  5. Log in to the WPMU install as admin, and create a new blog.  Edit the new blog, and change the Domain & FileUpload Url to myblog2.com and http://myblog2.com/files (all the other Urls are automatically updated when you save)
  6. Browse to http://myblog2.com !

Gotchas:

  • You can only have 1 wildcard Apache ServerAlias per IP

Hope that helps!


When to make technical stories?

During initial sprint planning, stories correspond to user features, and typically follow a

As a [user type]
I can [some action]
So that [some benefit]

structure.

Its important to keep the stories focused on features, rather than on tasks; because we need the users / product owner to be able to decide which stories to add or remove.  (A user cannot decide which tasks to add or remove, because the dependancies aren’t obvious).

However, during development of a particular story, you will often come across an area of the code that needs to be refactored.  A classic example is the case of removal of duplication; where as the design has evolved we discover additional areas of common functionality.

It can be tempting to attempt to work this refactoring into the current story, and if the refactoring is relatively small, this is a good idea.

However, in many cases the refactoring is too large to do without increasing the complexity of the story so much that it might not get finished in the current sprint.

This is the time to create a new “technical story”, which encompasses the refactoring (and perhaps any related work).

Its important that this block of work becomes a story to increase its visibility to the team, and to the product owner.  I’ve found that other team members always have useful input (hey, area Y of the team needs that too), and the product owner gets to prioritise the refactoring along with other stories.

This also makes plain to all the stakeholders why technical debt is increasing – if too many of these technical stories have been neglected in favour of new features.


Adding a prompt option to Html.Select in ASP.NET MVC

Digging around the source code to the ASP.NET MVC Source Refresh, I discovered a useful extension to the Html.Select helper method.

Say you want a select dropdown with a NULL case, which instructs the user to make a selection.

Eg: You want your first option to be:  ==Select==

To do so, call Html.Select with a htmlAttribute of prompt=”==Select==”

Like:

<%=Html.Select((“Quote.ClientId”), ViewData.Clients, “Name”,”Id”, ViewData.Quote.ClientId,0,false,new {prompt=”==Select==”})%>


alt.vs.team.system

Some thoughts on alternatives to the Visual Studio Team System for building webapps:

  • Requirement gathering
    • I like Axure (axure.com) for HTML prototyping ideas, and Visio is okay for architecture diagrams
  • Code editing
    • VS Pro + Resharper is pretty good. One of the best “step though debuggers” I’ve used
  • Source control
    • Subversion + TortoiseSVN. Any played with Git? Is there a good Git GUI tool?
  • Continuous Integration
  • Jetbrains TeamCity
  • Issue tracking / project website
    • I quite like Trac – wiki, milestones, good SVN integration. Have to maintain Python app though.
  • O/R mapper
    • NHibernate? DataSets? LINQtoSQL? What do you use?
  • TDD / BDD
    • ASP.NET MVC looks like its going in the right direction; but still early days
    • nUnit / mbUnit / VS built-in? Is there anything that comes close to rSpec in the Rails world for elegance?
    • Mocking frameworks? Moq has a nice syntax – most of the others seem overly complex (record/replay?!)
    • TestRunner? www.gallio.org looks like a good start, but still early days
    • Functional testing? Selenium? WatiN?
    • Continuous Integration server? Is there anything prettier than CruiseControl?
    • Load testing?
  • Logging
    • Log4Net>
  • Monitoring
    • Current favourite is Webperform
  • Support email handing
    • SupportSuite from QualityUnit has a nice Gmail style interface + KB

HOWTO: Ubuntu Server 7.0.4 on VMWare Server 1.0.4 on Windows XP

My local PHP/Symfony DEV environment is an Ubuntu Feisty Fawn server, running under VMWare on my Windows XP laptop. All the server side stuff runs on the Ubuntu VM, which mirrors the setup of my production host.

Install VMWare Server (free) from http://www.vmware.com/download/server/

This is a pretty straight forward Windows install, once you have registered and received the (free) license key via email

Your machine needs to have plenty of RAM, and a couple of gigs of free HDD space. (It works fine on my Dell Inspiron 510m, 1.6GHz, 1.25GB RAM laptop)

Install Ubuntu Feisty Fawn 7.04 VM

Download the installation CD ISO from http://www.ubuntu.com/getubuntu/download

Fire up the VMWare Server console, create a new VM. Use a NAT ethernet adapter. Make sure the VM’s CDROM points to the ISO you just downloaded.

Run through the installation proceedure, doing just the bare bones standard install. At the end, reboot, and don’t be alarmed at the crash:

Int 14: CR2 c1000000 err 00000002 EIP c03f3c3e CS 00000060 flags 00000006
Stack: 373c0046 00000000 ffffffff c0490000 00001400 00000080 00400000 ffffff80

The default server kernel won’t work with a VPC (http://www.virtualbox.org/ticket/289), so we need to install the desktop one.

* Re-Boot the server CD (NOT the server install), select recovery mode.
* Go through all the (recovery) steps ….
* Once you get to the command line :

# apt-get install linux-386
# apt-get remove linux-serverReboot, and login. Viola!

Finally, run ifconfig from the Ubuntu command line – to find the (current) IP address of the VM.


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