Chef recipe node hash doesn't have the same data as in chef server node data - ruby

Question

I have a conditional in a recipe that checks for some node data:
if node[:etc][:group].has_key?('someuser') and node[:etc][:group][:someuser][:gid] == 12345
# do something...
else
# do something else...
end
And I used knife node edit hostname.mydomain.com to add this data to my node object, as shown by
$ knife node show hostname.mydomain.com -m
Node Name: hostname.mydomain.com
Environment: ...
FQDN: hostname.mydomain.com
IP: ...
Run List: ...
Roles: ...
Recipes: ...
Platform: ...
Tags: ...
Attributes:..
etc:
group:
someuser:
gid: 12345
members:
tags: ...
However, the else clause is being executed instead of the if clause. I checked that this is the version of the recipe that is being run on the node (looked at the recipe that was downloaded to the node). I thought I had set up my node correctly to execute the if clause so why is the else clause executing? Thanks.

Answer 1

The node etc key is created by ohai (and is under a automatic key) and rewritten at each run, trying to set thoose attributes in node object won't work.
You can't override automatic attributes.
You can have more details on what is done on a chef run here and details about attributes here
What you can do here is creating the group in your recipe with the group resource and reload ohai data before entering the loop.
Exemple (heavily inspired from the doc ):
ohai "reload_passwd" do
action :nothing
plugin "etc"
end
group 'somegroup' do
gid 12345
notifies :reload, "ohai[reload_passwd]", :immediately
end
ruby_block "your code" do # in a ruby block to be run at converge time and not at compile time.
if node[:etc][:group].has_key?('someuser') and node[:etc][:group][:someuser][:gid] == 12345
# do something...
else
# do something else...
end
end
But the group creation could be in your else block, and next chef run will enter the if block as the group will exist.