Warning
The chef_gem and gem_package resources are both used to install Ruby gems. For any machine on which the chef-client is installed, there are two instances of Ruby. One is the standard, system-wide instance of Ruby and the other is a dedicated instance that is available only to the chef-client. Use the chef_gem resource to install gems into the instance of Ruby that is dedicated to the chef-client. Use the gem_package resource to install all other gems (i.e. install gems system-wide).
Use the chef_gem resource to install a gem only for the instance of Ruby that is dedicated to the chef-client. When a package is installed from a local file, it must be added to the node using the remote_file or cookbook_file resources.
The chef_gem resource works with all of the same properties and options as the gem_package resource, but does not accept the gem_binary
property because it always uses the CurrentGemEnvironment
under which the chef-client is running. In addition to performing actions similar to the gem_package resource, the chef_gem resource does the following:
Gem.clear_paths
after the action, ensuring that gem is aware of changes so that it can be required immediately after it is installedNote
In many cases, it is better to use the package resource instead of this one. This is because when the package resource is used in a recipe, the chef-client will use details that are collected by Ohai at the start of the chef-client run to determine the correct package application. Using the package resource allows a recipe to be authored in a way that allows it to be used across many platforms.
A chef_gem resource block manages a package on a node, typically by installing it. The simplest use of the chef_gem resource is:
chef_gem 'package_name'
which will install the named package using all of the default options and the default action (:install
).
The full syntax for all of the properties that are available to the chef_gem resource is:
chef_gem 'name' do clear_sources TrueClass, FalseClass compile_time TrueClass, FalseClass notifies # see description options String package_name String, Array # defaults to 'name' if not specified provider Chef::Provider::Package::Rubygems source String subscribes # see description timeout String, Integer version String, Array action Symbol # defaults to :install if not specified end
where
chef_gem
tells the chef-client to manage a package'name'
is the name of the package:action
identifies which steps the chef-client will take to bring the node into the desired stateclear_sources
, compile_time
, options
, package_name
, provider
, source
, timeout
, and version
are properties of this resource, with the Ruby type shown. See “Properties” section below for more information about all of the properties that may be used with this resource.This resource has the following actions:
:install
:nothing
:purge
:reconfig
:remove
:upgrade
This resource has the following properties:
clear_sources
Ruby Types: TrueClass, FalseClass
Set to true
to download a gem from the path specified by the source
property (and not from RubyGems). Default value: false
.
Note
Another approach is to use the gem_package resource, and then specify the gem_binary
location to the RubyGems directory that is used by Chef. For example:
gem_package 'package' do gem_binary Chef::Util::PathHelper.join(Chef::Config.embedded_dir,'bin','gem') action :install end
compile_time
Ruby Types: TrueClass, FalseClass
Controls the phase during which a gem is installed on a node. Set to true
to install a gem while the resource collection is being built (the “compile phase”). Set to false
to install a gem while the chef-client is configuring the node (the “converge phase”). Possible values: nil
(for verbose warnings), true
(to warn once per chef-client run), or false
(to remove all warnings). Recommended value: false
.
To suppress warnings for cookbooks authored prior to chef-client 12.1, use a respond_to?
check to ensure backward compatibility. For example:
chef_gem 'aws-sdk' do compile_time false if respond_to?(:compile_time) end
Warning
If you are using chef-sugar
—a community cookbook—it must be version 3.0.1 (or higher) to use the previous example. If you are using an older version of chef-sugar
, the following workaround is required:
chef_gem 'gem_name' do compile_time true if Chef::Resource::ChefGem.instance_methods(false).include?(:compile_time) end
See this blog post for more background on this behavior.
ignore_failure
Ruby Types: TrueClass, FalseClass
Continue running a recipe if a resource fails for any reason. Default value: false
.
notifies
Ruby Type: Symbol, ‘Chef::Resource[String]’
A resource may notify another resource to take action when its state changes. Specify a 'resource[name]'
, the :action
that resource should take, and then the :timer
for that action. A resource may notifiy more than one resource; use a notifies
statement for each resource to be notified.
A timer specifies the point during the chef-client run at which a notification is run. The following timers are available:
:before
:delayed
:immediate
, :immediately
The syntax for notifies
is:
notifies :action, 'resource[name]', :timer
options
Ruby Type: String
One (or more) additional options that are passed to the command.
package_name
Ruby Types: String, Array
The name of the package. Default value: the name
of the resource block See “Syntax” section above for more information.
provider
Ruby Type: Chef Class
Optional. Explicitly specifies a provider. See “Providers” section below for more information.
retries
Ruby Type: Integer
The number of times to catch exceptions and retry the resource. Default value: 0
.
retry_delay
Ruby Type: Integer
The retry delay (in seconds). Default value: 2
.
source
Ruby Type: String
Optional. The path to a package in the local file system.
subscribes
Ruby Type: Symbol, ‘Chef::Resource[String]’
A resource may listen to another resource, and then take action if the state of the resource being listened to changes. Specify a 'resource[name]'
, the :action
to be taken, and then the :timer
for that action.
A timer specifies the point during the chef-client run at which a notification is run. The following timers are available:
:before
:delayed
:immediate
, :immediately
The syntax for subscribes
is:
subscribes :action, 'resource[name]', :timer
timeout
Ruby Types: String, Integer
The amount of time (in seconds) to wait before timing out.
version
Ruby Types: String, Array
The version of a package to be installed or upgraded.
Where a resource represents a piece of the system (and its desired state), a provider defines the steps that are needed to bring that piece of the system from its current state into the desired state.
The chef-client will determine the correct provider based on configuration data collected by Ohai at the start of the chef-client run. This configuration data is then mapped to a platform and an associated list of providers.
Generally, it’s best to let the chef-client choose the provider, and this is (by far) the most common approach. However, in some cases, specifying a provider may be desirable. There are two approaches:
yum_package "foo" do
instead of package "foo" do
, script "foo" do
instead of bash "foo" do
, and so on—when availableprovider
property within the resource block to specify the long name of the provider as a property of a resource. For example: provider Chef::Provider::Long::Name
This resource has the following providers:
Chef::Provider::Package
, package
Chef::Provider::Package::Rubygems
, chef_gem
options
attribute.The following examples demonstrate various approaches for using resources in recipes. If you want to see examples of how Chef uses resources in recipes, take a closer look at the cookbooks that Chef authors and maintains: https://github.com/chef-cookbooks.
Compile time vs. converge time installation of gems
To install a gem while the chef-client is configuring the node (the “converge phase”), set the compile_time
property to false
:
chef_gem 'right_aws' do compile_time false action :install end
To install a gem while the resource collection is being built (the “compile phase”), set the compile_time
property to true
:
chef_gem 'right_aws' do compile_time true action :install end
Install MySQL for Chef
execute 'apt-get update' do ignore_failure true action :nothing end.run_action(:run) if node['platform_family'] == 'debian' node.set['build_essential']['compiletime'] = true include_recipe 'build-essential' include_recipe 'mysql::client' node['mysql']['client']['packages'].each do |mysql_pack| resources("package[#{mysql_pack}]").run_action(:install) end chef_gem 'mysql'
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https://docs-archive.chef.io/release/12-13/resource_chef_gem.html