snap_package resource

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Use the snap_package resource to manage snap packages on Debian and Ubuntu platforms.

Syntax

The snap_package resource has the following syntax:

snap_package 'name' do
  channel           String # default value: "stable"
  options           String, Array
  package_name      String, Array
  source            String
  timeout           String, Integer
  version           String, Array
  action            Symbol # defaults to :install if not specified
end

where:

  • snap_package is the resource.
  • name is the name given to the resource block.
  • action identifies which steps Chef Infra Client will take to bring the node into the desired state.
  • channel, options, package_name, source, timeout, and version are the properties available to this resource.

Actions

The snap_package resource has the following actions:

:install
Default. Install a package. If a version is specified, install the specified version of the package.
:lock
Locks the apt package to a specific version.
:purge
Purge a package. This action typically removes the configuration files as well as the package.
:reconfig
Reconfigure a package. This action requires a response file.
:remove
Remove a package.
:unlock
Unlocks the apt package so that it can be upgraded to a newer version.
:upgrade
Install a package and/or ensure that a package is the latest version.
:nothing
This resource block does not act unless notified by another resource to take action. Once notified, this resource block either runs immediately or is queued up to run at the end of a Chef Infra Client run.

Properties

The snap_package resource has the following properties:

channel

Ruby Type: String | Default Value: "stable"

The default channel. For example: stable.

options

Ruby Type: String, Array

One (or more) additional command options that are passed to the command.

package_name

Ruby Type: String, Array

An optional property to set the package name if it differs from the resource block’s name.

source

Ruby Type: String

The optional path to a package on the local file system.

timeout

Ruby Type: String, Integer

The amount of time (in seconds) to wait before timing out.

version

Ruby Type: String, Array

The version of a package to be installed or upgraded.

Common Resource Functionality

Chef resources include common properties, notifications, and resource guards.

Common Properties

The following properties are common to every resource:

ignore_failure

Ruby Type: true, false | Default Value: false

Continue running a recipe if a resource fails for any reason.

retries

Ruby Type: Integer | Default Value: 0

The number of attempts to catch exceptions and retry the resource.

retry_delay

Ruby Type: Integer | Default Value: 2

The retry delay (in seconds).

sensitive

Ruby Type: true, false | Default Value: false

Ensure that sensitive resource data is not logged by Chef Infra Client.

Notifications

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 a notifies statement for each resource to be notified.

A timer specifies the point during a Chef Infra 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 a Chef Infra 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
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 the nginx 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 example nginx) when a change is detected.

A timer specifies the point during a Chef Infra 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 a Chef Infra 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

Guards

A guard property can be used to evaluate the state of a node during the execution phase of a Chef Infra Client run. Based on the results of this evaluation, a guard property is then used to tell Chef Infra Client if it should continue executing a resource. A guard property accepts either a string value or a Ruby block value:

  • A string is executed as a shell command. If the command returns 0, the guard is applied. If the command returns any other value, then the guard property is not applied. String guards in a powershell_script run Windows PowerShell commands and may return true in addition to 0.
  • A block is executed as Ruby code that must return either true or false. If the block returns true, the guard property is applied. If the block returns false, the guard property is not applied.

A guard property is useful for ensuring that a resource is idempotent by allowing that resource to test for the desired state as it is being executed, and then if the desired state is present, for Chef Infra Client to do nothing.

The following properties can be used to define a guard that is evaluated during the execution phase of a Chef Infra Client run:

not_if
Prevent a resource from executing when the condition returns true.
only_if
Allow a resource to execute only if the condition returns true.

Examples