[chef] Re: Comparing the checksum of a cookbook_file in an non cookbook_file resource

[Daniel DeLeo < >]

On Monday, July 23, 2012 at 8:15 AM, 

 
 wrote:

> Hi All,
>  
> We have a deployment scenario where we are deploying a war to a Tomcat 
> server, and if a developer or ops person is in the exploded war directory 
> at the time, tomcat fails to redeploy the war file. We are not using the 
> application cookbook.
>  
> What I would like to do is add a file and directory resource to delete the 
> war file and exploded war directory if the war file's checksum has changed 
> prior to the cookbook_file line. I am assuming that the cookbook_file 
> resource always uses the checksum by default. Recipe snippet below:
>  
> #Caching
> file "#{node[:tomcat][:webapp_dir]}/perc-caching.war" do
> action :delete
> only_if [checksum of new cookbook file doesn't match installed cookbook 
> file]
> end
>  
> directory "#{node[:tomcat][:webapp_dir]}/perc-caching" do
> action :delete
> recursive true
> only_if [checksum of new cookbook file doesn't match installed cookbook 
> file]
> end
>  
> cookbook_file "#{node[:tomcat][:webapp_dir]}/perc-caching.war" do
> source "perc-caching.war"
> backup false
> owner "#{node[:tomcat][:user]}"
> group "#{node[:tomcat][:group]}"
> only_if [is this implied by the cookbook_file resource?]
> end
>  
> Is there a way to get the checksum of the cookbook_file that is currently 
> installed and comparing it to the checksum of the new cookbook file so that 
> the delete actions on the file and directory resources only run when the 
> file has changed?
>  
>  
> Any help,tips, comments, appreciated.
>  
> Thanks!
>  
> Nate Chadwick • Percussion Software
> (O) 781-835-1356 | 
> 
 
>  
> (mailto:
 )

You want to chain the resources together with notifications:  

http://wiki.opscode.com/display/chef/Resources#Resources-Notifications

Then you probably also want to use `action :nothing` on the other resources.

--  
Dan DeLeo