chef cookbook fails on ohai undefined method `[]' for nil:NilClass

Question

I'm working on a chef cookbook to set up a vanilla ubuntu 12.04.2 with nginx postgresql and unicorn on my vagrant box, but I'm getting into troubles with nginx, there's an exception

undefined method `[]' for nil:NilClass

when installing it that seem to relate to ohai configuration.

I've posted all I have here:

https://github.com/DonGiulio/mychef

here's the output from chef-solo:

Starting Chef Client, version 11.4.0
Compiling Cookbooks...

================================================================================
Recipe Compile Error in /var/chef/cookbooks/nginx/recipes/source.rb
================================================================================


NoMethodError
-------------
undefined method `[]' for nil:NilClass


Cookbook Trace:
---------------
  /var/chef/cookbooks/nginx/recipes/ohai_plugin.rb:27:in `from_file'
  /var/chef/cookbooks/nginx/recipes/source.rb:42:in `from_file'


Relevant File Content:
----------------------
/var/chef/cookbooks/nginx/recipes/ohai_plugin.rb:

 20:  #
 21:  
 22:  ohai 'reload_nginx' do
 23:    plugin 'nginx'
 24:    action :nothing
 25:  end
 26:  
 27>> template "#{node['ohai']['plugin_path']}/nginx.rb" do
 28:    source 'plugins/nginx.rb.erb'
 29:    owner  'root'
 30:    group  'root'
 31:    mode   '0755'
 32:    notifies :reload, 'ohai[reload_nginx]', :immediately
 33:  end
 34:  
 35:  include_recipe 'ohai::default'
 36:  


[2013-11-19T14:22:23+00:00] ERROR: Running exception handlers
[2013-11-19T14:22:23+00:00] ERROR: Exception handlers complete
Chef Client failed. 0 resources updated
[2013-11-19T14:22:23+00:00] FATAL: Stacktrace dumped to /var/chef/cache/chef-stacktrace.out
[2013-11-19T14:22:23+00:00] FATAL: NoMethodError: undefined method `[]' for nil:NilClass

and here's the stacktrace:

$ cat /var/chef/cache/chef-stacktrace.out
Generated at 2013-11-19 14:22:23 +0000
NoMethodError: undefined method `[]' for nil:NilClass
/var/chef/cookbooks/nginx/recipes/ohai_plugin.rb:27:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `instance_eval'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/cookbook_version.rb:346:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:151:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:132:in `block in include_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:131:in `each'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:131:in `include_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/dsl/include_recipe.rb:26:in `include_recipe'
/var/chef/cookbooks/nginx/recipes/source.rb:42:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `instance_eval'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/mixin/from_file.rb:30:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/cookbook_version.rb:346:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:151:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:139:in `block in compile_recipes'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:137:in `each'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:137:in `compile_recipes'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context/cookbook_compiler.rb:74:in `compile'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/run_context.rb:86:in `load'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/client.rb:224:in `setup_run_context'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/client.rb:467:in `do_run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/client.rb:200:in `run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application.rb:190:in `run_chef_client'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application/solo.rb:239:in `block in run_application'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application/solo.rb:231:in `loop'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application/solo.rb:231:in `run_application'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/lib/chef/application.rb:73:in `run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.4.0/bin/chef-solo:25:in `<top (required)>'
/usr/bin/chef-solo:23:in `load'
/usr/bin/chef-solo:23:in `<main>'

UPDATE 1 I'm provisioning the box with ruby-2.0.0-p247, is there a dependency on an earlier version of ruby maybe?

UPDATE 2 I've tried with ruby-1.9.3-p448, on a freshly provisioned box, same problem, no change.

Could you please help me?

thanks,

Answer 1

You haven't stated which version of the ohai and nginx cookbooks you're using.

While I can't answer your question I can provide some advice on managing your cookbooks by using a dependency manager (think bundler for cookbooks).

Install Berkshelf

gem install berkshelf

Create a Berkshelf file

$ cat Berksfile

site :opscode

cookbook "nginx"

And use this to download all the cookbooks associated with nginx:

$ berks install -p cookbooks
Using nginx (2.0.0)
Using apt (2.3.0)
Using bluepill (2.3.0)
Using rsyslog (1.9.0)
Using build-essential (1.4.2)
Using ohai (1.1.12)
Using runit (1.2.0)
Using yum (2.3.2)

The "-p" option places them in the "cookbooks" subdirectory:

$ ls -d cookbooks/*
cookbooks/apt       
cookbooks/build-essential  
cookbooks/ohai     
cookbooks/runit
cookbooks/bluepill  
cookbooks/nginx            
cookbooks/rsyslog  
cookbooks/yum

Answer 2

I have experienced the same error. You may find 3 other solutions to this problem, and an explanation why it's happening here on stackoverflow.

To mention one for those using Vagrant: Just include the recipe through Vagrantfile "chef.add_recipe()".

Using Berkshelf is obviously solving the issue, and I honestly like it. Just think that we should save the time of those who doesn't want to bother with installing new tools.

Answer 3

Ran into this trying to use community nexus cookbook. Solved it by specifying latest version of nginx cookbook in my metadata.rb: depends 'nginx', '>= 2.7.6'

The nexus cookbook metadata.rb specifies: depends "nginx", ">= 1.8.0"

So seems that chef will choose 1.8.0 when resolving deps unless you specify a newer version.

Answer 4

looks like ruby libraries were missing, I installed ruby by running following command on Ubuntu and it started working for me

apt-get install ruby