We have a web application which contains a bunch of content that the system operator can change (e.g. news and events). Occasionally we publish new versions of the software. The software is being tagged and stored in subversion. However, I'm a bit torn on how to best version control the content that may be changed independently. What are some mechanisms that people use to make sure that content is stored and versioned in a way that the site can be recreated or at the very least version controlled?
Keep everything in the DB, and give every transaction to the DB a timestamp. that way you can keep standard DB backups and load the site content at whatever date you want if the worst happens.
When you identify two set of files which have their own life cycle (software files on one side, "news and events" on the other, you know that:
- you can not versionned them together at the same time
- you should not put the same label
You need to save the "news and event" files separatly (either in the VCS or in a DB like Ian Jacobs suggests, or in a CMS - Content Management system), and find a way to link the tow together (an id, a timestamp, a meta-label, ...)
Do not forget you are not only talking about two different set of files in term of life cycle, but also about different set of files in term of their very natures:
Consider the terminology introduced in this SO question "Is asset management a superset of source control" by S.Lott
- software files: Infrastructure information, that is "representing the processing of the enterprise information asset". Your code is part of that asset and is managed by a VCS (Version Control System), as part of the Configuration management discipline.
- "news and events": Enterprise Information, that is data (not processing); this is often split between Content Managers and Relational Databases.
So not everything should end up in Subversion.
I suppose part of the answer depends on what CMS you're using, and how your web app is designed, but in general, I'd regard data such as news items or events as "content". In other words, it's not part of your application - it's the data which your application processes.
Of course, there will be versioning issues between your CMS code and your application code. You could manage this by defining the interface between the two. Personally, I'd publish the data to the web app as XML, which gives you the possibility of using XML schema to define exactly what the CMS is required to produce, and what the web app should expect to process.
This ought to mean that most changes in the web app can be made without a corresponding alteration in the rendering of the data. When functionality changes require this, you can create a new version of the schema and continue to make progress. In this scenario, I'd check the schema in with the web app code, but YMMV.
It isn't easy, and it gets more complicated again if you need additional data fields in your CMS. Expect to plan for a fairly complex release process (also depending on how complex your Dev-Test-Acceptance-Production scenario is.)
If you aren't using a CMS, then you should consider it. (Of course, if the operation is very small, it may still fall into the category where doing it by hand is acceptable.) Simply putting raw data into a versioning system doesn't solve the problem - you need to be able to control the format in which your data is published to the web app. Almost certainly this format should be something intended for consumption by software, and therefore not usually suitable for hand-editing by the kind of people who write news items or events.