Please add variable substitution

[wesparish]

It would be nice for Spiceweasel to have the ability to dynamically replace variables at runtime.

For example, it would be nice to be able to set a Spiceweasel variable "password" to "mysecret123" and use a replacement string throughout the rest of the manifest file. Furthermore, it would also be nice to have the ability to not only define key/value pairs for variables, but also to define key/special_value variables that allow prompting the user at runtime (eg: prompting for a sensitive password that cannot be stored in plaintext).

As a possible path to take (assuming 2 special strings, prompt_for_password (no echo) and prompt_for_text (echo)):

variables:
- root_password:
    value: "prompt_for_password"
- admin_user_name:
    value: "prompt_for_text"
- mray_pem_file:
    value: "~/.ssh/mray.pem"

nodes:
- serverA:
    run_list: role[base]
    options: -i <%= variables[:mray_pem_file] %> -x <%= variables[:admin_user_name] %> --sudo -P <%= variables[:root_password] %>

[rberger]

I just tested, that if you use the ruby style of spiceweasel configurations, you can do ruby stuff which includes effectively the things you are discussing (I didn't try prompting but I presume it would work)

For instance I wanted to set attributes inside of the spiceweasel config file and not in roles but I didn't want to embed json directly in the cluster option lines. So I did:

pod_attributes = {
  :pod => "default",
  :haproxy => {
    :balance_algorithm => "hdr(X-Real-IP)",
    :defaults_options => [
                          "httplog",
                          "dontlognull",
                          "forwardfor", 
                          "redispatch",
                          "httpchk GET /ui/"
                         ]
  }
}

and then in the related cluster section I used ruby string interpolation #{pod_attributes.to_json} to expand that out in the options . Note that the spiceweasel {{n}} mechanism for embedding the index of the instance still works too:

  "clusters"=>
  [
   {
     "qa"=>
     [
      {
        "ec2 1"=>
        {
          "run_list"=>"role[rm-pod] recipe[rm-pod] recipe[logstash::awesant]",
          "options"=>
          "-d chef-full  -S mykey -G qa -I ami-eb3c0183 -f m1.medium -j \'#{pod_attributes.to_json}\' -N qplb{{n}}.app
        }
      },
...

The main problem is if there is any syntax errors you get a rather meaningless error. I may get around to adding some stuff and do a pull request but probably not soon since I'm going to be away for a couple of weeks.