templates/agent-conf.d/riak.yaml.erb

init_config:

instances:
    -   url: <%= @url %>
<% if @tags and ! @tags.empty? -%>
        tags:
  <%- Array(@tags).each do |tag| -%>
    <%- if tag != '' -%>
            - <%= tag %>
    <%- end -%>
  <%- end -%>
<% end -%>