Validate that all roles have hosts

lib/mrsk/configuration.rb

@@ -80,7 +80,7 @@ class Mrsk::Configuration
   end
 
   def primary_web_host
-    role(:web).hosts.first
+    role(:web).primary_host
   end
 
   def traefik_hosts
@@ -196,6 +196,12 @@ class Mrsk::Configuration
         raise ArgumentError, "You must specify a password for the registry in config/deploy.yml (or set the ENV variable if that's used)"
       end
 
+      roles.each do |role|
+        if role.hosts.empty?
+          raise ArgumentError, "No servers specified for the #{role.name} role"
+        end
+      end
+
       true
     end
 

lib/mrsk/configuration/role.rb

@@ -7,6 +7,10 @@ class Mrsk::Configuration::Role
    @name, @config = name.inquiry, config
   end
 
+  def primary_host
+    hosts.first
+  end
+
   def hosts
     @hosts ||= extract_hosts_from_config
   end
@@ -55,7 +59,7 @@ class Mrsk::Configuration::Role
         config.servers
       else
         servers = config.servers[name]
-        servers.is_a?(Array) ? servers : servers["hosts"]
+        servers.is_a?(Array) ? servers : Array(servers["hosts"])
       end
     end