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# In Chef, when a resource is defined all its variables are evaluated during
# compile time and the execution of the resource takes place in converge phase.
# So if the value of a particular attribute is changed in converge
# (and not in compile) the resource will be executed with the old value.
# Example problem:
# Let's consider this situation where there are two steps involved in a recipe
# Step 1 is a Ruby block that changes a node attribute. Rubyblocks get executed
# in converge phase
# Step 2 is a Chef resource that makes use of the node attribute that was
# changed in Step 1
# ============= Without any modification to normal behavior ================= #
node[:test][:content] = "old content"
# Step 1
ruby_block "step1" do
block do
node[:test][:content] = "new content"
end
end
# Step 2
file "/tmp/some_file" do
owner "root"
group "root"
content node[:test][:content]
end
# =========================================================================== #
# file resource will still have the old content as it is set in the compile
# phase.
# ========================== With modified code ============================= #
node[:test][:content] = "old content"
# Step 1
ruby_block "step1" do
block do
node[:test][:content] = "new_content"
# Dynamically set the file resource's attribute
# Obtain the desired resource from resource_collection
file_r = run_context.resource_collection.find(:file => "/tmp/some_file")
# Update the content attribute
file_r.content node[:test][:content]
end
end
# Step 2
file "/tmp/some_file" do
owner "root"
group "root"
content node[:test][:content]
end
# =========================================================================== #
# The file resource will now have the updated content.
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