fix(fb_apache): render arrays inside of hash configs (facebook#218)

Summary:
## Description

This PR fixes a bug where the `template_hash_handler` in `fb_apache` silently skips over `Array` values. Now these values are rendered as if they were in the top-level `VirtualHost` directive.

For example:

```ruby
{
  ...
  'Location /foo' => {
    'Header' => [
      'unset Bar',
      'unset Baz',
    ],
    ...
```

...will now properly include multiple `Header ...` lines in the `Location /foo` directive.

## Impact

These values were ignored previously, so it is possible that it would cause changes in hosts where this was happening.

Pull Request resolved: facebook#218

Differential Revision: D45869664

fbshipit-source-id: 947ec76843416d411d4288c23bba4125de163185

Author: ericnorris

cookbooks/fb_apache/libraries/default.rb

@@ -28,37 +28,55 @@ def self.indentstr(indent)
       '  ' * indent
     end
 
-    # Map a hash to a apache-style syntax
-    def self.template_hash_handler(buf, indent, kw, data)
-      if HANDLERS.keys.include?(kw)
-        self.send(HANDLERS[kw], buf, indent, kw, data)
-        return
-      end
-      buf << indentstr(indent)
-      buf << "<#{kw}>\n"
-      data.each do |key, val|
+    def self.render_apache_conf(buf, depth, config)
+      config.each do |kw, val|
+        if HANDLERS.keys.include?(kw)
+          self.send(HANDLERS[kw], buf, depth, val)
+          next
+        end
+
+        indent = indentstr(depth)
+
         case val
-        when String
-          buf << indentstr(indent + 1)
-          buf << "#{key} #{val}\n"
+        when String, Integer
+          buf << indent
+          buf << "#{kw} #{val}\n"
+
+        when Array
+          val.each do |entry|
+            buf << indent
+            buf << "#{kw} #{entry}\n"
+          end
+
         when Hash
-          template_hash_handler(buf, indent + 1, key, val)
+          buf << indent
+          buf << "<#{kw}>\n"
+
+          render_apache_conf(buf, depth + 1, val)
+
+          buf << indent
+          buf << "</#{kw.split[0]}>\n"
+
+        else
+          fail "fb_apache: bad type for value of #{kw}: #{val.class}"
         end
       end
-      buf << indentstr(indent)
-      buf << "</#{kw.split[0]}>\n"
     end
 
     # Helper for rewrite syntax
-    def self.template_rewrite_helper(buf, _indent, _key, rules)
+    def self.template_rewrite_helper(buf, depth, rules)
+      indent = indentstr(depth)
+
       rules.each do |name, ruleset|
-        buf << indentstr(1)
+        buf << indent
         buf << "# #{name}\n"
+
         ruleset['conditions']&.each do |cond|
-          buf << indentstr(1)
+          buf << indent
           buf << "RewriteCond #{cond}\n"
         end
-        buf << indentstr(1)
+
+        buf << indent
         buf << "RewriteRule #{ruleset['rule']}\n\n"
       end
     end

cookbooks/fb_apache/templates/default/apache_conf.erb

@@ -3,5 +3,4 @@
 <%=   render 'apache_modules.erb' %>
 
 <%  end %>
-<%= render 'apache_conf.erb',
-        :variables => {:conf => node['fb_apache']['extra_configs']} %>
+<% FB::Apache.render_apache_conf(_buf, 0, node['fb_apache']['extra_configs']) %>

cookbooks/fb_apache/templates/default/fb_apache.conf.erb

@@ -3,7 +3,7 @@
 <% realvhost = conf['_virtualhost'] || vhost %>
 <VirtualHost <%= realvhost %>>
 <%   conf.reject! { |x, y| x == '_virtualhost' } %>
-<%=  render 'apache_conf.erb', :variables => {:conf => conf} %>
+<%   FB::Apache.render_apache_conf(_buf, 1, conf) %>
 </VirtualHost>
 
 <% end %>