[chef-dev] Setting node attributes with a knife plugin

[< >]

Hi,

I was wondering if anyone has an idea how to decently change a single 
attribute
of a node when that attribute is passed on the command line as an argument for
a knife plugin.

Let's say the plugin's name is 'node set_attr'
E.g. if I run
  knife node set_attr NODENAME apache.dir "/tmp"
I want to achieve that node['apache']['dir'] == "/tmp".

The only way I came up with is something along the lines of:

  @nodename = @name_args[0]
  @attribute = @name_args[1]
  @new_value = @name_args[2]
  
  @node = Chef::Node.load(@nodename)
  
  ruby_command = "@node." + @attribute + "=" + @new_value
  eval(ruby_command)
  @node.save

However imo eval'ing this is kind of ugly, are there any better ways?

My actual use case is the creation of encrypted attribute values via [1] and
applying them directly to a node, however the encryption stuff itself is
trivial. The only thing I am not very happy about* - as mentioned above - is
using eval to set the attribute.

If this is not the right place to ask ruby questions about non-chef-core
related things, I apologize sincerely.

Kind regards,

Oscar

* besides not having tests for the plugin and catching all sorts of errors 
that
could occur

[1] https://github.com/oscarschneider/openssldemo/blob/master/node_secret.rb