Chef - Read a file from git repo at runtime and use parse value in recipe

Question

I would like to read a file from a checkout git repository to parse a config file and use this data to perform few resources commands.

git "/var/repository" do
    action :sync
end

config = JSON.parse(File.read("/var/repository/config.json" ))
config.each do |job, flags|
    #do some resources stuff here
end

This will not work because the file doesn't exist at compile time:

================================================================================ Recipe Compile Error in /var/chef/cache/cookbooks/... ================================================================================

Errno::ENOENT

---

No such file or directory - /var/repository/config.json

I where trying to load the file in ruby_block and perform the Chef resource actions there, but this didn't worked. Also setting the parsed config to a variable and use it outside of the ruby_block didn't work.

ruby_block "load config" do
    block do
        config = JSON.parse(File.read("/var/repository/config.json"))
        #node["config"] = config doesn't work - node["config"] will not be set

        config.each do |job, flags|
            #do some stuff - will not work because Chef context is missing
        end
    end
end

Any idea how I could read the file at runtime and used the parsed values in my recipe?

Answer 1

You may also find it helpful to use lazy evaluation in scenarios like this.

In some cases, the value for an attribute cannot be known until the execution phase of a chef-client run. In this situation, using lazy evaluation of attribute values can be helpful. Instead of an attribute being assigned a value, it may instead be assigned a code block.