In chef I Have a ruby_block where I am changing permissions and ownership of a directory. How can I do a check where the permissions are only changed if they have not already been changed by the " FileUtils.chown" statement? I need to do this within the ruby_block if possible because i am ganna have other code in the ruby block. What would my "unless" statement be? Here is my code:
ruby_block 'exe' do
block do
FileUtils.chmod 0755, '/make/news'
FileUtils.chown('root', 'root', '/make/news')
end
end
The correct way to do this is to use Chef's file resource:
file '/make/news' do
mode 0755
owner 'root'
group 'root'
end
You're going down the road of trying to re-write the file resource which is not a good idea.
Using the Chef Resource's not_if Guard
Chef resources share a number of common functions. The ruby_block resource supports the not_if property as a conditional guard. The general format is:
ruby_block 'custom chmod' do
block do
#
end
not_if { true }
end
So, you could program your logic this way, but it will eventually bite you badly. Chef often works better if you use a file or directory resource declaratively using a separate block to manage permissions, and then (if necessary) chain it with a notification from some other block that needs a given permission set. For example:
directory '/make/news' do
mode '0755'
owner 'root'
group 'root'
action :nothing
end
ruby_block 'do something with news' do
block do
#
end
only_if { true }
notifies :create, 'directory[/make/news]', :before
end
That said, the goal of configuration management is to continuously converge, so I'd strongly question whether creating this interdependency between resource blocks is truly necessary in the first place. If possible, just converge your directory permissions every time to enforce them. While this may create a sequencing dependency within your recipe, a more declarative approach often simplifies cookbook and recipe debugging in the long run. Your individual mileage may vary.
Related
I have the following code to figure out where Java is located on the box. Java comes with our application and what Java version that is included with the application differs.
def app_java_home
if Dir.exist?("#{app_home}/jre-server/linux")
Dir.chdir("#{app_home}/jre-server/linux") do
Dir.glob('jdk*').select { |f| File.directory? f }[0]
end
end
end
Then, in my cookbook I have
aws_s3_file "#{app_download_path}/#{app_s3['archive_file']}" do
bucket app_s3['bucket']
remote_path app_s3['remote_path']
region aws_region
not_if { ::Dir.exists?(app_bin_dir) }
not_if { ::File.exists?("#{app_download_path}/#{app_s3['archive_file']}") }
end
execute 'extract' do
user 'root'
command "unzip #{app_download_path}/#{app_s3['archive_file']} > /dev/null"
not_if { ::Dir.exists?("#{app_home}/ourapp") }
only_if { ::File.exists?("#{app_download_path}/#{app_s3['archive_file']}") }
end
execute 'move' do
user 'root'
command "mv #{app_download_path}/ourapp/ #{app_install_path}"
not_if { ::Dir.exists?(app_home) }
end
cookbook_file "#{app_java_home}/jre/lib/security/local_policy.jar" do
source %W[#{app_release}/local_policy.jar default/local_policy.jar]
owner app_user_name
group app_group_name
mode 0755
end
cookbook_file "#{app_java_home}/jre/lib/security/US_export_policy.jar" do
source %W[#{app_release}/US_export_policy.jar default/US_export_policy.jar]
owner app_user_name
group app_group_name
mode 0755
end
However, the two cookbook_file resources fails because it can't find the directory:
No such file or directory # dir_chdir - /ourapp/jre-server/linux/
After a lot of googling, I've come to the conclusion that it's a .. "missmatch" (?) between compile time and run time of the recipes. Basically, if I understand it correctly, it tries to run the cookbook_file resource(s) first but fails. So never downloads, unpacks and installs the app artefact.
I've tried running app_java_home when the directory exists, and it does seem to work the way I want it..
I tried putting the cookbook_file resources in a ruby_block, but then I instead get:
undefined method `cookbook_file' for Chef::Resource::RubyBlock
The app_java_home .. function (?) used to look like this:
def app_java_home
"#{app_home}/jre-server/linux/#{jdk_version}"
end
Where jdk_version came from the databag. This worked fine, but we have a long standing bug/feature request in our system where it sometimes happens that "they" get the version they put in the databag wrong, causing all sorts of problems.. So they want a way to remove this dependency and instead "figure this out" dynamically.
Ruby and Chef isn't my forte, so I'm not sure what to try next. I have found references to Chef::Resources::CookbookFile (which, if I understand it, could/should be used inside ruby_blocks), but can't find any examples or documentation about it. The link on RubyDocs is broken.
Adding an answer here for a better explanation.
Any (Ruby) code that is not within any of the Chef resources, will run in Compile phase
All resource declarations will run in Convergence phase in the order they are defined
Thankfully, there is a way to make resources run in Compile phase if so required. Though IMHO it should be done sparingly and in exceptional cases.
As per your comment aws_s3_file and execute resources are the ones that unpack the app (and create the directory). In this case, it seems you want them to run in compile phase.
Prior to Chef client 16.0
Use the run_action option with the action that should be performed at the compile time. For example execute resource takes action :run:
# Note action ":nothing" and "run_action"
execute 'extract' do
user 'root'
command "unzip #{app_download_path}/#{app_s3['archive_file']} > /dev/null"
not_if { ::Dir.exists?("#{app_home}/ourapp") }
only_if { ::File.exists?("#{app_download_path}/#{app_s3['archive_file']}") }
action :nothing
end.run_action(:run)
Chef client 16.0 onwards
We can add a common property to the resources. Example with execute resource:
# Note the extra property "compile_time"
execute 'extract' do
user 'root'
command "unzip #{app_download_path}/#{app_s3['archive_file']} > /dev/null"
not_if { ::Dir.exists?("#{app_home}/ourapp") }
only_if { ::File.exists?("#{app_download_path}/#{app_s3['archive_file']}") }
compile_time true
end
And finally to answer the subject of the question:
Chef use cookbook_file in ruby block
This is not possible. Refer to the first point on the top. If we want Ruby code to run during converge (instead of compile), we put it within the ruby_block resource. So it can contain code like (for example):
ruby_block 'get directory' do
block do
def app_java_home
"#{app_home}/jre-server/linux/#{jdk_version}"
end
end
end
With the help of #seshadri_c, I finally managed to solve the problem! It took some doing, because I kept misunderstanding the suggestions etc.
So this is what I came up with (for posterity):
def jdk_version(required = true)
base_dir = "#{app_home}/jre-server/linux"
if Dir.exist?("#{base_dir}")
Dir.chdir("#{app_home}/jre-server/linux") do
Dir.glob("jdk*").each do |f|
if File.directory?(f)
return "#{f}"
end
end
end
end
end
def app_java_home
return "#{app_home}/jre-server/linux/#{jdk_version}"
end
Turns out I need to get just the version, individually, as well, so I rearranged the functions a bit. I'm sure it could be written much cleaner, but here the trick was to use return instead of puts/print! Well, I'm a programmer, but not a Ruby programmer so didn't know that was an option..
Then, in the cookbook, I added the .run_action() where needed. I didn't need them for the cookbook_file, which simplified things a bit:
aws_s3_file "#{app_download_path}/#{app_s3['archive_file']}" do
bucket app_s3['bucket']
remote_path app_s3['remote_path']
region aws_region
not_if { ::Dir.exists?(app_bin_dir) }
not_if { ::File.exists?("#{app_download_path}/#{app_s3['archive_file']}") }
end.run_action(:create)
execute 'extract' do
user 'root'
command "unzip #{app_download_path}/#{app_s3['archive_file']} > /dev/null"
not_if { ::Dir.exists?("#{app_home}/app") }
only_if { ::File.exists?("#{app_download_path}/#{app_s3['archive_file']}") }
end.run_action(:run)
execute 'move' do
user 'root'
command "mv #{app_download_path}/app/ #{app_install_path}"
not_if { ::Dir.exists?(app_home) }
end.run_action(:run)
# JCE Unlimited Strength Jurisdiction Policy Files
cookbook_file "#{app_java_home}/jre/lib/security/local_policy.jar" do
source %W[#{app_release}/local_policy.jar default/local_policy.jar]
owner app_user_name
group app_group_name
mode 0755
end
cookbook_file "#{app_java_home}/jre/lib/security/US_export_policy.jar" do
source %W[#{app_release}/US_export_policy.jar default/US_export_policy.jar]
owner app_user_name
group app_group_name
mode 0755
end
With all that, everything is running exactly when they're supposed to and everything seems to be working.
I need a way to run parts of chef recipes only in case of converge action in Test Kitchen.
I found a way to do it for ChefSpec:
unless defined?(ChefSpec)
cookbook_file "/home/#{node['user']}/script.sh" do
source 'install.sh'
owner node['user']
mode '0755'
action :create
end
end
How I can do it for Kitchen tool?
This requirement has been discussed in detail on a feature request on Github.
There are two ways to do this. One is to define an environment variable such as TEST_KITCHEN, then use it in recipe with if condition, only_if or not_if guards.
Below should work:
Set the environment variable:
export TEST_KITCHEN="1"
Run the resource conditionally:
if ENV['TEST_KITCHEN']
cookbook_file "/home/#{node['user']}/script.sh" do
source 'install.sh'
owner node['user']
mode '0755'
action :create
end
end
Other way is to use a node attribute, something like node['test_kitchen'] set to true and use it to run actions conditionally.
cookbook_file "/home/#{node['user']}/script.sh" do
source 'install.sh'
owner node['user']
mode '0755'
action :create
only_if { node['test_kitchen'] }
end
The challenge prompt is above, and my latest attempt is below. The directories and files are created as expected, and the read-out after executing chef-apply multipleCopies.rb tells me the files are linked, but when I update any one of the files, the others do not follow suit. Any ideas? Here is my code:
for x in 1..3
directory "multipleCopy#{x}" do
mode '0755'
action :create
end
end
file "multipleCopy1/secret.txt" do
mode '0755'
action :create
end
for x in 2..3
link "multipleCopy#{x}/secret.txt" do
to "multipleCopy1/secret.txt"
link_type :hard
subscribes :reload, "multipleCopy1/secret.txt", :immediately
end
end
Note: For less headache, I am testing the recipe locally before uploading to the ubuntu server referenced in the prompt, which is why my file paths are different and why I have not yet included the ownership properties.
So a file hard link doesn't seem to be what the question is going for (though I would say your solution is maybe better since this is really not what Chef is for, more on that later). Instead they seem to want you to have three actually different files, but sync the contents.
So first the easy parts, creating the directories and the empty initial files. It's rare to see those for loops used in Ruby code, though it is syntactically valid:
3.times do |n|
directory "/var/save/multipleCopy#{n+1}" do
owner "ubuntu"
group "root"
mode "755"
end
file "/var/save/multipleCopy#{n+1}/secret.txt" do
owner "root
group "root"
mode "755"
end
end
But that doesn't implement the hard part of sync'ing the files. For that we need to first analyze the mtimes on the files and use the most recent as the file content to set.
latest_file = 3.times.sort_by { |n| ::File.mtime("/var/save/multipleCopy#{n+1}/secret.txt") rescue 0 }
latest_content = ::File.read("/var/save/multipleCopy#{latest_file+1}/secret.txt") rescue nil
and then in the file resource:
file "/var/save/multipleCopy#{n+1}/secret.txt" do
owner "root
group "root"
mode "755"
content latest_content
end
As for this not being a good use of Chef: Chef is about writing code which asserts the desired state of the machine. In the case of files like this, rather than doing this kind of funky stuff to check if a file has been edited, you would just say that Chef owns the file content for all three and if you want to update it, you do it via your cookbook (and then usually use a template or cookbook_file resource).
I just started using chef and don't know much about ruby.
I have problems understanding the language-syntax used in recipes.
Say, I create a directory in a cookbook in recipes/default.rb like:
directory "/home/test/mydir" do
owner "test"
mode "0755"
action :create
recursive true
end
I assume this is part of a valid ruby script. What do lines like owner "test" mean? Is this a function call, a variable assignment or something else entirely?
Chef is written in Ruby and makes an extensive use of Ruby ability to design custom DSL. Almost every chef configuration file is written with a Ruby-based DSL.
This means that in order to use chef effectively you should be familiar with the basic of Ruby syntax including
Grammar
Data types (the main difference compared to other languages are Symbols)
Blocks
You don't need to know a lot about metaprogramming in Ruby.
The case of the code you posted is an excellent example of a Ruby based DSL. Let me explain it a little bit.
# Call the method directory passing the path and a block
# containing some code to be evaluated
directory "/home/test/mydir" do
# chown the directory to the test user
owner "test"
# set the permissions to 0555
mode "0755"
# create the directory if it does not exists
action :create
# equivalent of -p flag in the mkdir
recursive true
end
Blocks are a convenient way to specify a group of operations (in this case create, set permissions, etc) to be evaluated in a single context (in this case in the context of that path).
Let's break it down.
directory "/home/test/mydir" do
...
end
You are just calling a global method defined by Chef called directory, passing one argument "/home/test/mydir", and a block (everything between the do and end).
This block is probably excecuted in a special scope created by Chef in which all of the options (owner, mode, action, etc.) are method.
I'm learning chef at the moment and I'm trying to write everything in a way that repeated provisioning doesn't break anything.
I have a server that is deployed on the machine and then there is some code loaded into it. The next time of provisioning I like to test first if the code has been loaded already. And I want to do it in a generic way because I use it in different recipes.
My idea would be to define a function/defintion/etc.. I can call the function which tests the condition and returns a value. My hopes would be that I can use this function/... in a not_if clause for other actions.
Is there a way to do this in chef with a defintion/action/provider/... or would I need to add some rubyish stuff somewhere?
Resources in Chef all have conditional execution.
The not_if and only_if statements can take a shell command as a string or a ruby block to determine if they should perform their action or not.
user "myuser" do
not_if "grep myuser /etc/password"
action :create
end
You might have a node attribute and use that as your conditional or call a ruby method that returns true or false.
template "/tmp/somefile" do
mode "0644"
source "somefile.erb"
not_if { node[:some_value] }
end
https://web.archive.org/web/20111120120013/http://wiki.opscode.com/display/chef/Resources#Resources-ConditionalExecution