I just published a gist on Ansible 1.3 Conditional Execution
It is a very complete example with comments. I find the conditional expressions to be ridiculously hard to get right in Ansible. I don’t have a good model of what’s going on under the surface (as I don’t know Python) so I often get it wrong.
What makes it even harder is that there has been at least three different variants over the course from version 0.7 to 1.3. Now ‘when’ seems to be the recommended one, but I used to have better luck with the earlier versions.
One thing that makes it hard is that the type of the variable is very important, and it’s not obvious what that is. It seems it may be interpreted as a string even if defined as False. The framework doesn’t really help you. I think a language like this should be able to ‘do what I mean’.
Here is the official Ansible docs on this.