How I can capture values in command line and add to recipe?

Question

I am new to Chef and Ruby

I need to pass two variables to Chef on the command line and have those variables available in a recipe.

How I can capture these values and get them in Chef?

I need something like this:

before_deploy command 
  execute param1 param2
deploy{ param1/param2}

Where param1 and param2 get their values at run-time from the command-line.

Answer 1

When you provision the machine by running

chef-solo

or

chef-client

you cannot provide any arguments to these commands that can be visible to recipes. Chef recipes work only with attributes. Good thing (or not so good) is that attributes can be set from many different places: roles, nodes, environments and json file.

The workaround that is nearest to your request is

• Create a json-file on the machine
• Pass it when running chef-client or chef-solo
• Use attributes in the recipe

For example: apache config.

create json file: my_attrs.json

{ 
  "apache": {
    "listen_port": "81",
    "listen_path": "/myapp"
  }
}

and then use them in your recipe:

node[:apache][:listen_port]
node[:apache][:listen_path]

Run chef-client or chef-solo with -j flag.

chef-solo -j my_attrs.json

If my_attrs.json is on some remote server, then you can provide a url.

chef-solo -j http://remote.host/path/my_attrs.json

Answer 2

If your file is named example.rb

ruby example.rb argument1 argument2

Then

ARGV.each do|a|
  puts "Argument: #{a}"
end

Output:

Argument: argument1
Argument: argument2

Answer 3

You can set variables inside recipes by calling commands

nodename = `cat /etc/chef/client.rb | grep "node_name" | sed -e 's/\<node_name\>//g' | sed '/^$/d;s/[[:blank:]]//g' | sed 's/\"//g'`

And then use the variable for other chef blocks

execute "echo nodename for node #{nodename}"
 command "echo #{nodename}"
 action :run
 only_if {nodename == "node1"}
end

This will get the node.name attribute from the client.rb file without asking for it to the chef server.