chef_gem resource¶
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 gem 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:
- Runs its actions immediately, before convergence, allowing a gem to be used in a recipe immediately after it is installed
- Runs
Gem.clear_paths
after the action, ensuring that gem is aware of changes so that it can be required immediately after it is installed
Syntax¶
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 gem 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 true, false
compile_time true, false
gem_binary String
include_default_source true, false
notifies # see description
options String
package_name String # defaults to 'name' if not specified
source String, Array
subscribes # see description
timeout String, Integer
version String
action Symbol # defaults to :install if not specified
end
where:
chef_gem
is the resource.name
is the name given to the resource block.action
identifies which steps the chef-client will take to bring the node into the desired state.clear_sources
,include_default_source
,gem_binary
,options
,package_name
,source
,timeout
, andversion
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.
Actions¶
This resource has the following actions:
:install
- Default. Install a gem. If a version is specified, install the specified version of the gem.
:nothing
- Define this resource block to do nothing until notified by another resource to take action. When this resource is notified, this resource block is either run immediately or it is queued up to be run at the end of the Chef Client run.
:purge
- Purge a gem. This action typically removes the configuration files as well as the gem.
:reconfig
- Reconfigure a gem. This action requires a response file.
:remove
- Remove a gem.
:upgrade
- Install a gem and/or ensure that a gem is the latest version.
Properties¶
The chef_gem resource has the following properties:
clear_sources
Ruby Type: true, false | Default Value:
false
Set to
true
to download a gem from the path specified by thesource
property (and not from RubyGems).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 'gem_name' do gem_binary Chef::Util::PathHelper.join(Chef::Config.embedded_dir,'bin','gem') action :install end
compile_time
Ruby Type: true, false | Default Value:
false
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 tofalse
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), orfalse
(to remove all warnings). Recommended value:false
.gem_binary
Ruby Type: String
The path of a gem binary to use for the installation. By default, the same version of Ruby that is used by the chef-client will be installed.
include_default_source
Ruby Type: true, false | Default Value:
true
Set to
false
to not includeChef::Config[:rubygems_url]
in the sources.New in Chef Client 13.0.
ignore_failure
Ruby Type: true, false | Default Value:
false
Continue running a recipe if a resource fails for any reason.
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 notify more than one resource; use anotifies
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
- Specifies that the action on a notified resource should be run before processing the resource block in which the notification is located.
:delayed
- Default. Specifies that a notification should be queued up, and then executed at the end of the Chef Client run.
:immediate
,:immediately
- Specifies that a notification should be run immediately, per resource notified.
The syntax for
notifies
is:notifies :action, 'resource[name]', :timer
options
Ruby Type: String, Hash, Array,
Options for the gem install, either a Hash or a String. When a hash is given, the options are passed to Gem::DependencyInstaller.new, and the gem will be installed via the gems API. When a String is given, the gem will be installed by shelling out to the gem command. Using a Hash of options with an explicit gem_binary will result in undefined behavior.
package_name
Ruby Type: String
The name of the gem. Default value: the
name
of the resource block. See “Syntax” section above for more information.retries
Ruby Type: Integer | Default Value:
0
The number of times to catch exceptions and retry the resource.
retry_delay
Ruby Type: Integer | Default Value:
2
The retry delay (in seconds).
source
Ruby Type: String, Array
Optional. The URL, or list of URLs, at which the gem package is located. This list is added to the source configured in
Chef::Config[:rubygems_url]
(see also include_default_source) to construct the complete list of rubygems sources. Users in an ‘airgapped’ environment should setChef::Config[:rubygems_url]
to their local RubyGems mirror.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.Note that
subscribes
does not apply the specified action to the resource that it listens to - for example:file '/etc/nginx/ssl/example.crt' do mode '0600' owner 'root' end service 'nginx' do subscribes :reload, 'file[/etc/nginx/ssl/example.crt]', :immediately end
In this case the
subscribes
property reloads thenginx
service whenever its certificate file, located under/etc/nginx/ssl/example.crt
, is updated.subscribes
does not make any changes to the certificate file itself, it merely listens for a change to the file, and executes the:reload
action for its resource (in this examplenginx
) when a change is detected.A timer specifies the point during the Chef Client run at which a notification is run. The following timers are available:
:before
- Specifies that the action on a notified resource should be run before processing the resource block in which the notification is located.
:delayed
- Default. Specifies that a notification should be queued up, and then executed at the end of the Chef Client run.
:immediate
,:immediately
- Specifies that a notification should be run immediately, per resource notified.
The syntax for
subscribes
is:subscribes :action, 'resource[name]', :timer
timeout
Ruby Type: String, Integer
The amount of time (in seconds) to wait before timing out.
version
Ruby Type: String
The version of a gem to be installed or upgraded.
Examples¶
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
apt_update
node.override['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'