[chef] Re: Capture output from a command or read contents from a file

[Hector Castro < >]

This is an interesting case.  I wrote a step yesterday to write the mdadm 
configuration file and used the following:

        execute "mdadm_detail" do
          command "mdadm --detail --scan >> /etc/mdadm.conf"
          not_if "cat /etc/mdadm.conf | grep ARRAY"
        end

Outside of capturing the `mdadm --detail --scan` output using Ruby and 
passing it to `mdadm.conf` through template variables, do people have 
alternate approaches?

--
Hector

On Jan 17, 2012, at 4:05 PM, Harlan Barnes wrote:

> What's the proper way to read output from a command or contents from a file 
> to use in a variable (to pass to a template for example) in a chef recipe? 
> Or is this bad form in some way?
> 
> I couldn't figure out how to do it with a built in resource so I gave up 
> and went to some ruby ... but weird things happen. It seems to execute the 
> ruby code in the wrong place (too early ... before figlet is installed). 
> I'm probably doesn't something wrong, however.
> 
> Any suggestions?
> 
> # installs the figlet RPM
> include_recipe "figlet"
> 
> banner = ''
> io = IO.popen("/usr/bin/figlet -w 160 #{node.name}")
> io.each do |line|
>   banner += line
> end
> 
> template "/etc/motd" do
>   source "motd.erb"
>   mode 0644
>   variables(
>     :banner => banner
>   )
> end