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batch resource

Resources Reference page


Use the batch resource to execute a batch script using the cmd.exe interpreter on Windows. The batch resource creates and executes a temporary file (similar to how the script resource behaves), rather than running the command inline. Commands that are executed with this resource are (by their nature) not idempotent, as they are typically unique to the environment in which they are run. Use not_if and only_if to guard this resource for idempotence.

Syntax


A batch resource block executes a batch script using the cmd.exe interpreter:

batch 'echo some env vars' do
  code <<-EOH
    echo %TEMP%
    echo %SYSTEMDRIVE%
    echo %PATH%
    echo %WINDIR%
    EOH
end

The full syntax for all of the properties that are available to the batch resource is:

batch 'name' do
  architecture               Symbol
  code                       String
  command                    String, Array
  creates                    String
  cwd                        String
  flags                      String
  group                      String, Integer
  guard_interpreter          Symbol
  interpreter                String
  returns                    Integer, Array
  timeout                    Integer, Float
  user                       String
  password                   String
  domain                     String
  action                     Symbol # defaults to :run if not specified
end

where:

  • batch 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.
  • architecture, code, command, creates, cwd, flags, group, guard_interpreter, interpreter, returns, timeout, user, password and domain 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


The batch resource has the following actions:

: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.
:run
Run a batch file.

Properties


The batch resource has the following properties:

architecture
Ruby Type: Symbol

The architecture of the process under which a script is executed. If a value is not provided, Chef Infra Client defaults to the correct value for the architecture, as determined by Ohai. An exception is raised when anything other than :i386 is specified for a 32-bit process. Possible values: :i386 (for 32-bit processes) and :x86_64 (for 64-bit processes).

code
Ruby Type: String | REQUIRED

A quoted (” “) string of code to be executed.

command
Ruby Type: String, Array

The name of the command to be executed.

creates
Ruby Type: String

Prevent a command from creating a file when that file already exists.

cwd
Ruby Type: String

The current working directory from which the command will be run.

flags
Ruby Type: String

One or more command line flags that are passed to the interpreter when a command is invoked.

group
Ruby Type: String, Integer

The group name or group ID that must be changed before running a command.

guard_interpreter
Ruby Type: Symbol | Default Value: :batch

When this property is set to :batch, the 64-bit version of the cmd.exe shell will be used to evaluate strings values for the not_if and only_if properties. Set this value to :default to use the 32-bit version of the cmd.exe shell.

interpreter
Ruby Type: String

The script interpreter to use during code execution. Changing the default value of this property is not supported.

returns
Ruby Type: Integer, Array | Default Value: 0

The return value for a command. This may be an array of accepted values. An exception is raised when the return value(s) do not match.

timeout
Ruby Type: Integer, Float | Default Value: 3600

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

user
Ruby Type: String

The user name of the user identity with which to launch the new process. The user name may optionally be specified with a domain, i.e. domainuser or user@my.dns.domain.com via Universal Principal Name (UPN)format. It can also be specified without a domain simply as user if the domain is instead specified using the domain attribute. On Windows only, if this property is specified, the password property must be specified.

password
Ruby Type: String

Windows only: The password of the user specified by the user property. This property is mandatory if user is specified on Windows and may only be specified if user is specified. The sensitive property for this resource will automatically be set to true if password is specified.

domain
Ruby Type: String

Windows only: The domain of the user user specified by the user property. If not specified, the user name and password specified by the user and password properties will be used to resolve that user against the domain in which the system running Chef Infra Client is joined, or if that system is not joined to a domain it will resolve the user as a local account on that system. An alternative way to specify the domain is to leave this property unspecified and specify the domain as part of the user property.


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.

Properties

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


The following examples demonstrate various approaches for using the batch resource in recipes:

Unzip a file, and then move it

To run a batch file that unzips and then moves Ruby, do something like:

batch 'unzip_and_move_ruby' do
  code <<-EOH
    7z.exe x #{Chef::Config[:file_cache_path]}/ruby-1.8.7-p352-i386-mingw32.7z
      -oC:\\source -r -y
    xcopy C:\\source\\ruby-1.8.7-p352-i386-mingw32 C:\\ruby /e /y
    EOH
end

batch 'echo some env vars' do
  code <<-EOH
    echo %TEMP%
    echo %SYSTEMDRIVE%
    echo %PATH%
    echo %WINDIR%
    EOH
end

or:

batch 'unzip_and_move_ruby' do
  code <<-EOH
    7z.exe x #{Chef::Config[:file_cache_path]}/ruby-1.8.7-p352-i386-mingw32.7z
      -oC:\\source -r -y
    xcopy C:\\source\\ruby-1.8.7-p352-i386-mingw32 C:\\ruby /e /y
    EOH
end

batch 'echo some env vars' do
  code 'echo %TEMP%\\necho %SYSTEMDRIVE%\\necho %PATH%\\necho %WINDIR%'
end

Run a command as an alternate user

Note: When Chef is running as a service, this feature requires that the user that Chef runs as has ‘SeAssignPrimaryTokenPrivilege’ (aka ‘SE_ASSIGNPRIMARYTOKEN_NAME’) user right. By default only LocalSystem and NetworkService have this right when running as a service. This is necessary even if the user is an Administrator.

This right can be added and checked in a recipe using this example:

# Add 'SeAssignPrimaryTokenPrivilege' for the user
Chef::ReservedNames::Win32::Security.add_account_right('<user>', 'SeAssignPrimaryTokenPrivilege')

# Check if the user has 'SeAssignPrimaryTokenPrivilege' rights
Chef::ReservedNames::Win32::Security.get_account_right('<user>').include?('SeAssignPrimaryTokenPrivilege')

The following example shows how to run mkdir test_dir from a Chef Infra Client run as an alternate user.

# Passing only username and password
batch 'mkdir test_dir' do
 code "mkdir test_dir"
 cwd Chef::Config[:file_cache_path]
 user "username"
 password "password"
end

# Passing username and domain
batch 'mkdir test_dir' do
 code "mkdir test_dir"
 cwd Chef::Config[:file_cache_path]
 domain "domain"
 user "username"
 password "password"
end

# Passing username = 'domain-name\\username'. No domain is passed
batch 'mkdir test_dir' do
 code "mkdir test_dir"
 cwd Chef::Config[:file_cache_path]
 user "domain-name\\username"
 password "password"
end

# Passing username = 'username@domain-name'. No domain is passed
batch 'mkdir test_dir' do
 code "mkdir test_dir"
 cwd Chef::Config[:file_cache_path]
 user "username@domain-name"
 password "password"
end