Chef

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gem_package

A resource defines the desired state for a single configuration item present on a node that is under management by Chef. A resource collection—one (or more) individual resources—defines the desired state for the entire node. During every chef-client run, the current state of each resource is tested, after which the chef-client will take any steps that are necessary to repair the node and bring it back into the desired state.

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 gem_package resource to manage gem packages that are only included in recipes. When a package is installed from a local file, it must be added to the node using the remote_file or cookbook_file resources.

Note

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. That said, there are scenarios where using an application-specific package is preferred.

Syntax

The syntax for using the gem_package resource in a recipe is as follows:

gem_package "name" do
  attribute "value" # see attributes section below
  ...
  action :action # see actions section below
end

where

  • gem_package tells the chef-client to use the Chef::Provider::Rubygems provider during the chef-client run
  • name is the name of the resource block; when the package_name attribute is not specified as part of a recipe, name is also the name of the package
  • attribute is zero (or more) of the attributes that are available for this resource
  • :action is the step that the resource will ask the provider to take during the chef-client run

Gem Package Options

The RubyGems package provider attempts to use the RubyGems API to install gems without spawning a new process, whenever possible. A gems command to install will be spawned under the following conditions:

  • When a gem_binary attribute is specified (as a hash, a string, or by a .gemrc file), the provider will run that command to examine its environment settings and then again to install the gem.
  • When install options are specified as a string, the provider will span a gems command with those options when installing the gem.
  • The omnibus installer will search the PATH for a gem command rather than defaulting to the current gem environment. As part of enforce_path_sanity, the bin directories area added to the PATH, which means when there are no other proceeding RubyGems, the installation will still be operated against it.

Specify with Hash

If an explicit gem_binary parameter is not being used with the gem_package resource, it is preferable to provide the install options as a hash. This approach allows the provider to install the gem without needing to spawn an external gem process.

The following RubyGems options are available for inclusion within a hash and are passed to the RubyGems DependencyInstaller:

  • :env_shebang
  • :force
  • :format_executable
  • :ignore_dependencies
  • :prerelease
  • :security_policy
  • :wrappers

For more information about these options, see the RubyGems documentation: http://rubygems.rubyforge.org/rubygems-update/Gem/DependencyInstaller.html.

Example

gem_package "bundler" do
  options(:prerelease => true, :format_executable => false)
end

Specify with String

When using an explicit gem_binary, options must be passed as a string. When not using an explicit gem_binary, the chef-client is forced to spawn a gems process to install the gems (which uses more system resources) when options are passed as a string. String options are passed verbatim to the gems command and should be specified just as if they were passed on a command line. For example, --prerelease for a pre-release gem.

Example

gem_package "nokogiri" do
  gem_binary("/opt/ree/bin/gem")
  options("--prerelease --no-format-executable")
end

Specify with .gemrc File

Options can be specified in a .gemrc file. By default the gem_package resource will use the Ruby interface to install gems which will ignore the .gemrc file. The gem_package resource can be forced to use the gems command instead (and to read the .gemrc file) by adding the gem_binary attribute to a code block.

Example

gem_package "nokogiri" do
  gem_binary "gem"
end

Actions

This resource has the following actions:

Action Description
:install Default. Use to install a package. If a version is specified, use to install the specified version of a package.
:upgrade Use to install a package and/or to ensure that a package is the latest version.
:reconfig Use to reconfigure a package. This action requires a response file.
:remove Use to remove a package.
:purge Use to purge a package. This action typically removes the configuration files as well as the package.

Attributes

This resource has the following attributes:

Attribute Description
gem_binary An attribute for the gem_package provider that is used to specify a gems binary. By default, the same version of Ruby that is used by the chef-client will be installed.
options One (or more) additional options that are passed to the command.
package_name The name of the package. Default value: the name of the resource block. (See “Syntax” section above for more information.)
provider Optional. Use to explicitly specify a provider. (See “Providers” section below for more information.)
response_file Optional. The direct path to the file used to pre-seed a package.
source Optional. The URL at which the gem package is located.
version The version of a package to be installed or upgraded.

Providers

The chef-client will attempt to determine the correct provider during the chef-client run, and then choose the best/correct provider based on configuration data collected at the start of the chef-client run. In general, a specific provider does not need to be specified. In situations where a specific provider must be specified, there are two approaches:

  • Using a provider’s short name as the name of the resource, e.g. short_name "foo" do
  • Using the provider attribute to specify the long name as an attribute of a resource, e.g. provider Chef::Provider::Long::Name

Whenever possible, try using the short name first, and then use the long name when necessary.

This resource has the following providers:

Long name Short name Notes
Chef::Provider::Package package When this short name is used, the chef-client will attempt to determine the correct provider during the chef-client run.
Chef::Provider::Package::Rubygems gem_package Can be used with the options attribute.

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/opscode-cookbooks.

Install a gems file from the local file system

gem_package "right_aws" do
  source "/tmp/right_aws-1.11.0.gem"
  action :install
end

Use the ignore_failure common attribute

gem_package "syntax" do
  action :install
  ignore_failure true
end