Saturday, October 28, 2006

Development V's Production Environment

An interesting post on software environmental issues by Mitch Denny caught my attention today, not only because he sent a link around on our internal tech list, but because it's something that I think continually trips up a lot of developers (myself included). Mitch basically argues (and I agree) that development should be done in the same basic environment as the production system, he plays this off against infrastructure people who tend to want to keep a gap between production and development for safety reasons, I mean wo knows what wholes these crazy developers are going to poke in our top-notch security infrastructure.

Most of my experience has been in the shrink wrapped software industry ans as such, there is little point trying to match development and production environments, so in this case I suggest develop on the environment that makes the developers most productive, but then make sure you test, using whatever virtualisation technology you prefer, on ALL platforms in your supported platform matrix.

With enterprise development however, I would say that one should develop in an environment as close as is practicable to the production environment. It never ceases to amaze me the amount of problems that arise because of differences between the development and production environments. Have you ever heard a developer say "gee, it doesn't do that on my machine". The closer you make development environments to the production environment, the less you'll hear this anoying phrase.

The flip side of the coin is that developers need to understand fairly well the differences between their development environment and their production environment. One thing that has bitten me in the past, and a lot of other developers as well is the difference between IIS and the Visual Studio Development Web Server (The web server formerly known as Cassini). There are a number of differneces, and also a number of reasons that developers like to use it over IIS. One major difference which always seems to trip me up is that Cassini passes every requested file through the ASP.Net pipeline, as opposed to IIS which will serve a lot of files normally (ie *.css, *.jpg, *.gif, *.png, *.html, etc...), and only pass the ASP.Net specific files (*.aspx, *.asmx, *.ashx etc...) through to the ASP.Net pipeline. When you first start a project you don't really notice any difference until you think to yourself, "gee, it would be nice to add forms authentication now", and so you put in the standard <deny user="?" /> element and all of a sudden your login page has no graphics and doesn't look anything like how you designed it. This is because Cassini is sending all of you image and css files through the ASP.Net pipeline and they are getting blocked by the Security module because you are not authenticated... yet.

Tags: ASP.Net, IIS

1 comment:

  1. A good balance I have found is for developers to use their own (isolated) environments for development and unit testing and have their code system tested on a separate test environment that will mimic the production environment. In any case, the test environment should be able to be pristine prior to each test. Using the actual production environment for development is fraught with danger (particularly when messing with AD) and allowing each developer to have his/her own environment allows for increased robustness ("hey it works for me... so what's different between our environments??").
    And yes, vmware or similar virtualisation techniques is extremely helpful (essential?) for this type of thing.