friendly_errors.txt

User-friendly error messages

AutomateIt provides user-friendly error messages that make it easier to fix problems in recipes and templates. These pinpoint the cause and show code snippets.

For example, one of the sample recipes is executed — but there‘s a problem and the output is shown below.

The message is telling us the error happened in the ‘examples/basic/recipes/install.rb’ recipe at line 47. The first snippet shows the end of a failed TemplateManager render call.

In the second code snippet, we see there was a problem with the ERB template ‘dist/myapp_server.erb’. This template failed at line 5 because it couldn‘t find a variable called pat.

With the help of the second snippet, we quickly see that there‘s a typo — that bad variable should have been path. Problem solved!

  root@kagami> automateit -n examples/basic/recipes/install.rb
  !! Problem with recipe 'examples/basic/recipes/install.rb' at line 47

     41            :to => "/etc/init.d/myapp_server",
     42            :mode => 0555,
     43            :locals => {
     44               :path => lookup(:path),
     45               :user => lookup(:user),
     46               :port => lookup(:port),
   * 47            }
     48     )
     49

  (NestedError) Problem with template 'dist/myapp_server.erb' at line 5:

     1 #!/usr/bin/env ruby
     2
     3 user = "<%=user%>"
     4 port = "<%=port%>"
   * 5 path = "<%=pat%>"
     6 pid = "mongrel.pid"
     7

  (NameError) undefined local variable or method `pat' for #<AutomateIt::TemplateManager::ERB:0xb78a4e8c>
    /home/igal/workspace/automateit/app/lib/helpful_erb.rb:60:in `result'
    /home/igal/workspace/automateit/app/lib/automateit/template_manager/erb.rb:105:in `render'
    (eval):2:in `render'
    examples/basic/recipes/install.rb:47:in `invoke'

  => Use 'automateit --trace' to see complete backtrace