powershell_script resource¶
Use the powershell_script resource to execute a script using the Windows PowerShell interpreter, much like how the script and script-based resources—bash, csh, perl, python, and ruby—are used. The powershell_script is specific to the Microsoft Windows platform and the Windows PowerShell interpreter.
The powershell_script 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.
Changed in 12.19 to support windows alternate user identity in execute resources
Syntax¶
A powershell_script resource block executes a batch script using the Windows PowerShell interpreter. For example, writing to an interpolated path:
powershell_script 'write-to-interpolated-path' do
code <<-EOH
$stream = [System.IO.StreamWriter] "#{Chef::Config[:file_cache_path]}/powershell-test.txt"
$stream.WriteLine("In #{Chef::Config[:file_cache_path]}...word.")
$stream.close()
EOH
end
The full syntax for all of the properties that are available to the powershell_script resource is:
powershell_script 'name' do
architecture Symbol
code String
command String, Array
convert_boolean_return true, false
creates String
cwd String
environment Hash
flags String
group String, Integer
guard_interpreter Symbol
interpreter String
notifies # see description
returns Integer, Array
sensitive true, false
subscribes # see description
timeout Integer, Float
user String
password String
domain String
action Symbol # defaults to :run if not specified
elevated true, false
end
where
powershell_script
is the resourcename
is the name of the resource blockcommand
is the command to be run andcwd
is the location from which the command is runaction
identifies the steps the chef-client will take to bring the node into the desired statearchitecture
,code
,command
,convert_boolean_return
,creates
,cwd
,environment
,flags
,group
,guard_interpreter
,interpreter
,returns
,sensitive
,timeout
,user
,password
,domain
andelevated
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:
:nothing
- Inherited from execute resource. Prevent a command from running. This action is used to specify that a command is run only when another resource notifies it.
:run
- Default. Run the script.
Properties¶
This 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, the chef-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
A quoted (” “) string of code to be executed.
command
Ruby Type: String, Array
The name of the command to be executed. Default value: the
name
of the resource block. See “Syntax” section above for more information.convert_boolean_return
Ruby Type: true, false | Default Value:
false
Return
0
if the last line of a command is evaluated to be true or to return1
if the last line is evaluated to be false.When the
guard_interpreter
common attribute is set to:powershell_script
, a string command will be evaluated as if this value were set totrue
. This is because the behavior of this attribute is similar to the value of the"$?"
expression common in UNIX interpreters. For example, this:powershell_script 'make_safe_backup' do guard_interpreter :powershell_script code 'cp ~/data/nodes.json ~/data/nodes.bak' not_if 'test-path ~/data/nodes.bak' end
is similar to:
bash 'make_safe_backup' do code 'cp ~/data/nodes.json ~/data/nodes.bak' not_if 'test -e ~/data/nodes.bak' end
creates
Ruby Type: String
Inherited from execute resource. Prevent a command from creating a file when that file already exists.
cwd
Ruby Type: String
Inherited from execute resource. The current working directory from which a command is run.
environment
Ruby Type: Hash
Inherited from execute resource. A Hash of environment variables in the form of
({"ENV_VARIABLE" => "VALUE"})
. (These variables must exist for a command to be run successfully.)flags
Ruby Type: String
A string that is passed to the Windows PowerShell command. Default value (Windows PowerShell 3.0+):
-NoLogo, -NonInteractive, -NoProfile, -ExecutionPolicy Bypass, -InputFormat None
.group
Ruby Type: String, Integer
Inherited from execute resource. The group name or group ID that must be changed before running a command.
guard_interpreter
Ruby Type: Symbol | Default Value:
:powershell_script
When this property is set to
:powershell_script
, the 64-bit version of the Windows PowerShell shell will be used to evaluate strings values for thenot_if
andonly_if
properties. Set this value to:default
to use the 32-bit version of the cmd.exe shell.ignore_failure
Ruby Type: true, false | Default Value:
false
Continue running a recipe if a resource fails for any reason.
interpreter
Ruby Type: String
The script interpreter to use during code execution. Changing the default value of this property is not supported.
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
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).
returns
Ruby Type: Integer, Array | Default Value:
0
Inherited from execute resource. 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.
sensitive
Ruby Type: true, false | Default Value:
false
Ensure that sensitive resource data is not logged by the chef-client.
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: Integer, Float
Inherited from execute resource. The amount of time (in seconds) a command is to wait before timing out. Default value:
3600
.user
Ruby Type: String | Default Value:
nil
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. domain\user 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. Default value: nil. 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 specified by the user property. Default value: nil. 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 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.
elevated
Ruby Type: true, false
Determines whether the script will run with elevated permissions to circumvent User Access Control (UAC) interactively blocking the process.
This will cause the process to be run under a batch login instead of an interactive login. The user running Chef needs the “Replace a process level token” and “Adjust Memory Quotas for a process” permissions. The user that is running the command needs the “Log on as a batch job” permission.
Because this requires a login, the
user
andpassword
properties are required.
Guards¶
A guard property can be used to evaluate the state of a node during the execution phase of the chef-client run. Based on the results of this evaluation, a guard property is then used to tell the chef-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 returntrue
in addition to0
. - A block is executed as Ruby code that must return either
true
orfalse
. If the block returnstrue
, the guard property is applied. If the block returnsfalse
, 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 the chef-client to do nothing.
Attributes
The following properties can be used to define a guard that is evaluated during the execution phase of the chef-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
.
Arguments
The following arguments can be used with the not_if
or only_if
guard properties:
:user
Specify the user that a command will run as. For example:
not_if 'grep adam /etc/passwd', :user => 'adam'
:group
Specify the group that a command will run as. For example:
not_if 'grep adam /etc/passwd', :group => 'adam'
:environment
Specify a Hash of environment variables to be set. For example:
not_if 'grep adam /etc/passwd', :environment => { 'HOME' => '/home/adam' }
:cwd
Set the current working directory before running a command. For example:
not_if 'grep adam passwd', :cwd => '/etc'
:timeout
Set a timeout for a command. For example:
not_if 'sleep 10000', :timeout => 10
Examples¶
The following examples demonstrate different 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.
Write to an interpolated path
powershell_script 'write-to-interpolated-path' do
code <<-EOH
$stream = [System.IO.StreamWriter] "#{Chef::Config[:file_cache_path]}/powershell-test.txt"
$stream.WriteLine("In #{Chef::Config[:file_cache_path]}...word.")
$stream.close()
EOH
end
Change the working directory
powershell_script 'cwd-then-write' do
cwd Chef::Config[:file_cache_path]
code <<-EOH
$stream = [System.IO.StreamWriter] "C:/powershell-test2.txt"
$pwd = pwd
$stream.WriteLine("This is the contents of: $pwd")
$dirs = dir
foreach ($dir in $dirs) {
$stream.WriteLine($dir.fullname)
}
$stream.close()
EOH
end
Change the working directory in Microsoft Windows
powershell_script 'cwd-to-win-env-var' do
cwd '%TEMP%'
code <<-EOH
$stream = [System.IO.StreamWriter] "./temp-write-from-chef.txt"
$stream.WriteLine("chef on windows rox yo!")
$stream.close()
EOH
end
Pass an environment variable to a script
powershell_script 'read-env-var' do
cwd Chef::Config[:file_cache_path]
environment ({'foo' => 'BAZ'})
code <<-EOH
$stream = [System.IO.StreamWriter] "./test-read-env-var.txt"
$stream.WriteLine("FOO is $env:foo")
$stream.close()
EOH
end
Evaluate for true and/or false
Use the convert_boolean_return
attribute to raise an exception when certain conditions are met. For example, the following fragments will run successfully without error:
powershell_script 'false' do
code '$false'
end
and:
powershell_script 'true' do
code '$true'
end
whereas the following will raise an exception:
powershell_script 'false' do
convert_boolean_return true
code '$false'
end
Use the flags attribute
powershell_script 'Install IIS' do
code <<-EOH
Import-Module ServerManager
Add-WindowsFeature Web-Server
EOH
flags '-NoLogo, -NonInteractive, -NoProfile, -ExecutionPolicy Unrestricted, -InputFormat None, -File'
guard_interpreter :powershell_script
not_if '(Get-WindowsFeature -Name Web-Server).Installed'
end
Rename computer, join domain, reboot
The following example shows how to rename a computer, join a domain, and then reboot the computer:
reboot 'Restart Computer' do
action :nothing
end
powershell_script 'Rename and Join Domain' do
code <<-EOH
...your rename and domain join logic here...
EOH
not_if <<-EOH
$ComputerSystem = gwmi win32_computersystem
($ComputerSystem.Name -like '#{node['some_attribute_that_has_the_new_name']}') -and
$ComputerSystem.partofdomain)
EOH
notifies :reboot_now, 'reboot[Restart Computer]', :immediately
end
where:
- The powershell_script resource block renames a computer, and then joins a domain
- The reboot resource restarts the computer
- The
not_if
guard prevents the Windows PowerShell script from running when the settings in thenot_if
guard match the desired state - The
notifies
statement tells the reboot resource block to run if the powershell_script block was executed during the chef-client run
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-client run as an alternate user.
# Passing only username and password
powershell_script 'mkdir test_dir' do
code "mkdir test_dir"
cwd Chef::Config[:file_cache_path]
user "username"
password "password"
end
# Passing username and domain
powershell_script '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
powershell_script '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
powershell_script 'mkdir test_dir' do
code "mkdir test_dir"
cwd Chef::Config[:file_cache_path]
user "username@domain-name"
password "password"
end
# Work around User Access Control (UAC)
powershell_script 'mkdir test_dir' do
code "mkdir test_dir"
cwd Chef::Config[:file_cache_path]
user "username"
password "password"
elevated true
end