[chef] Re: What can be used in not_if / how to build something that can be used?

[Vladimir Girnet < >]

not_if / only_if are based on exit code of check line.
You can have a simple script that will check if code should be uploaded
or not, and the script should return ether 0 / 1

For example, using execute resource:

execute "code_upload" do
  command "my_code_upload_script"  # this is the script that will upload
code
  action :run
  not_if "my_code_exists_check_script" # this is the script that will
check if code is already uploaded or not
end

Another good way may be to move everything to ruby, and use more ruby in
your recipes


On 9/21/11 3:11 PM, Norbert Hartl wrote:
> Hi,
>
> this is my first post and I'm learning chef at the moment. I'm using 
> veewee, vagrant and chef to bootstrap an appliance for me. The basic 
> machine is bootstrapped and running. Nice tool you did :)
>
> Now I try to integrate the stuff a little bit more and make it more 
> reliable. One of the things I do is to check condition that decide if a 
> action needs to take place or not. In the tutorials/examples this almost 
> all the time done using something like "unless File.exists....". I need to 
> do something similar but for another running component. The task is to load 
> some code into server. In order not to load the code every single 
> provisioning time I like to check if it has been loaded already. I know how 
> to do it with execute/script/bash... but then I have to write the specific 
> action it has to do (that follows the condition) within the action. But I 
> need the capabiltiy of checking things in the server quite often. So I'm 
> looking for slightly more generic way of achieving it.
> I don't know if it is possible to create a definition function, an action 
> or anything that returns a value and therefor can be used in not_if, 
> only_if, etc. I had the impression LWRP could help but know I don't know 
> how. My last ressort seems to be writing a library that I include in a 
> recipe. But I wanted to ask if there is a better possibility to achieve the 
> same. 
>
> I hope I could explain my problem in a proper way. I'm not used to chef 
> terminology, yet. Sorry for that.
>
> thanks in advance,
>
> Norbert
>

-- 
Vladimir Girnet
Infrastructure Engineer
Tacit Knowledge
http://www.tacitknowledge.com