Attributes - Learning Chef - page 169

$ touch attributes\default.rb

By default, the Chef Development Kit does not create an attributes directory until you tell it
to generate an attribute file. Chef Client, on the other hand, always creates the directory, but
leaves it up to you to create the default.rb attribute file by hand.

Now, let's set an attribute in our attributes file following the form outlined in Figure 8-1 . Be-
fore you edit attributes/default.rb the file will have no content, as shown in Example 8-4 .

Example 8-4. chefdk/motd-attributes/attributes/default.rb
default [ 'motd-attributes' ][ 'company' ] = 'Chef'

By convention, when attributes are set in a cookbook's attribute file, the values are expected
to be namespaced under a top-level key matching the cookbook name. Then all the key/value
pairs are contained within the top-level key; for example, the default['motd-attrib-
utes']['company'] value is the string 'Chef' in this example, as the cookbook name in the
metadata.rb file is motd-attributes . Also, following the form outlined in Figure 8-1 , the
attribute uses the default precedence level.

Let's also set an attribute value in our recipe, as seen in Example 8-5 , following the form in
Figure 8-2 .

Example 8-5. chefdk/motd-attributes/recipes/default.rb
node . default [ 'motd-attributes' ][ 'message' ] = "It's a wonderful day today!"

template '/etc/motd' ddo
source 'motd.erb'
mode '0644'
end

end

Update the motd.erb template as shown in Example 8-6 . You can access attributes from any
source under the node object: attribute file values, values set in recipes, or values set auto-
matically by ohai . They're all just the corresponding node values.

Example 8-6. chefdk/motd-attributes/templates/default/motd.erb
Welcome to < %= node['motd-attributes']['company'] %>
<%= node [ 'motd-attributes' ][ 'message' ] %>
The hostname of this node is <%= node['hostname'] %>
The IP address of this node is <%= node [ 'ipaddress' ] %>