[chef] Re: Chef and find a json file generated from a previous recipe

["Brian O'Connell" < >]

David - 

  I can't do the details of a chef run justice in an email, but it is important to know the a chef run has multiple phases. A compilation phase and a converge phase.  Ruby code that you write in your recipe is evaluated in the compilation phase and resources that make changes to system are generally executed in the converge phase.  You can see http://docs.chef.io/chef_client.html for more information.

 

  The reason your host file is null on the first run is because your resource in the other recipe hasn't yet written the file to disk.  One method to tackle this is to read the file content in using a lazy block.  Your code would become: 

 

template "/etc/zookeeper/conf/zoo.cfg" do
  path "/etc/zookeeper/conf/zoo.cfg"
  source "cloudera.zoo.cfg.erb"
  owner "root"
  group "root"
  mode "0644"
  variables lazy { :zookeeper => File.read("#{Chef::Config[:file_cache_path]}/zookeeper_hosts"  }
  notifies :restart, resources(:service => "zookeeper-server")
end

 

Depending on your use case, you may want to reconsider using elements like if File.exists? as checks.  Should the recipe continue if a file is missing or should the chef run fail to indicate that a problem has occurred?  It seems like that element being nil was a problem, perhaps the chef run should abort if that file is missing? 

 

I don't know if its an anti-pattern, but I try to avoid using the file_cache_path for elements my system needs for configuration.  I assume files in that path may be wiped out at any time and even if another recipe has a job of putting a file in there during subsequent chef runs I like to see as few resources as possible change without an external change being initiated.

 

 

 

-
Brian O'Connell, STSM
IBM - Continuous Availability Services
 

 

 

----- Original message -----
From: David Montgomery < >
To:
Cc:
Subject: [chef] Chef and find a json file generated from a previous recipe
Date: Tue, Jun 2, 2015 6:45 AM
 

Hi,
 

I have two recipes. 
 

The job of the first recipe is the run a python script and to save to disk a json file.
 

The job of the second recipe is to read the the json file into a hash and pass to a template.
 

Below is the second recipe

if File.exists?("#{Chef::Config[:file_cache_path]}/zookeeper_hosts")
    zookeeper_hosts = File.read("#{Chef::Config[:file_cache_path]}/zookeeper_hosts")
end

template "/etc/zookeeper/conf/zoo.cfg" do
  path "/etc/zookeeper/conf/zoo.cfg"
  source "cloudera.zoo.cfg.erb"
  owner "root"
  group "root"
  mode "0644"
  variables :zookeeper => zookeeper_hosts
  notifies :restart, resources(:service => "zookeeper-server")
end

 

On the first run of chef, all works but the zookeeper_hosts is Null.  If I rerun chef after the intial run then zookeeper_hosts has the proper hash even though the previous run generated the hash.

 

How can I load the json file generated from json created from a previous recipe?
 

Thanks