[chef] Re: Re: How to extend node[:apache][:listen_ports] from within another recipe?

[Torben Knerr < >]

On Mon, Oct 29, 2012 at 5:04 PM, Daniel DeLeo < " target="_blank"> > wrote:

On Thursday, October 25, 2012 at 1:58 PM, Torben Knerr wrote:

Hi Chefs,

I'm trying to add another port to `node[:apache][:listen_ports]` from within my own recipe, e.g. like this:

```

if not node[:apache][:listen_ports].include? "8080"

  node.override[:apache][:listen_ports] = node[:apache][:listen_ports] << "8080"

end

```

This does not work really well as it requires another chef run to take effect. I assume this is because it runs _after_ the /etc/apache2/ports.conf template resource (from the apache2 recipe) has been created with the orginal `node[:apache][:listen_ports]` which did not contain port 8080 at that time yet.

I have also tried to notify the /etc/apache2/ports.conf template resource after adding port 8080 to the apache listen ports, but this didn't work as well:

```

ruby_block "update apache listen port" do

  block do

    node.override[:apache][:listen_ports] = node[:apache][:listen_ports] << "8080"

  end

  notifies :create, resources(:template => "#{node[:apache][:dir]}/ports.conf")

  not_if { node[:apache][:listen_ports].include? "8080" } 

end

```

I suspect the resource gets in fact notified, but still has the "outdated" state as it does not re-evaluate `node[:apache][:listen_ports]` now that port 8080 has been added.

Is there a way to do this in a single Chef run?

Thanks,

Torben

You have a few options. One is to use attributes in roles, which will be merged in after the attributes files have been read, but before the recipes are read. Arrays will be combined via set union, so you can add more values to the array that way.

Another option is to modify the attribute in a recipe that runs before the apache2 recipe. For example, you can have a local-apache2 cookbook with a recipe that modifies the attributes and then calls include_recipe to run the apache2 recipe.

The final (and probably least good) option is to grab the template resource after it's been defined and modify it:

    template_res = resources(:template => "/etc/apache2/ports.conf")

    template_res.variables[:listen_ports] << 8080

or something along those lines.

-- 

Daniel DeLeo

Thanks! I wasn't aware of the last method you mentioned, it's actually pretty close to what I wanted. 

Not sure though if I should make my recipe that much implict so that it adds its own port under the hood, or if I should rather require explicit configuration via role attributes. Not sure yet, but let's see...

Torben