script Resource
This page is generated from the Chef Infra Client source code.To suggest a change, edit the script.rb file and submit a pull request to the Chef Infra Client repository.
Use the script resource to execute scripts using a specified interpreter, such as Bash, csh, Perl, Python, or Ruby. This resource may also use any of the actions and properties that are available to the execute resource. 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.
This resource is the base resource for several other resources used for scripting on specific platforms. For more information about specific resources for specific platforms, see the following topics: - bash - csh - ksh - perl - python - ruby Changed in 12.19 to support windows alternate user identity in execute resources
Syntax
A script resource block typically executes scripts using a specified interpreter, such as Bash, csh, Perl, Python, or Ruby:
script 'extract_module' do
interpreter "bash"
cwd ::File.dirname(src_filepath)
code <<-EOH
mkdir -p #{extract_path}
tar xzf #{src_filename} -C #{extract_path}
mv #{extract_path}/*/* #{extract_path}/
EOH
not_if { ::File.exist?(extract_path) }
end
where:
interpreter
specifies the command shell to usecwd
specifies the directory from which the command is runcode
specifies the command to run It is more common to use the script-based resource that is specific to the command shell. Chef has shell-specific resources for Bash, csh, ksh, Perl, Python, and Ruby. The same command as above, but run using the bash resource:bash 'extract_module' do cwd ::File.dirname(src_filepath) code <<-EOH mkdir -p #{extract_path} tar xzf #{src_filename} -C #{extract_path} mv #{extract_path}/*/* #{extract_path}/ EOH not_if { ::File.exist?(extract_path) } end
The full syntax for all of the properties that are available to the script resource is:
script 'name' do
code String
creates String
cwd String
domain String
environment Hash
flags String
group String, Integer
interpreter String
password String
returns Integer, Array # default value: 0
timeout Integer, String, Float # default value: 3600
umask String, Integer
user String, Integer
action Symbol # defaults to :run if not specified
end
where:
script
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.code
,creates
,cwd
,domain
,environment
,flags
,group
,interpreter
,password
,returns
,timeout
,umask
, anduser
are the properties available to this resource.
Actions
The script 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 command. (default)
Properties
The script resource has the following properties:
code
- Ruby Type: String |
REQUIRED
A quoted string of code 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.
domain
- Ruby Type: String
Windows only: The domain of the user 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.
environment
- Ruby Type: Hash
A Hash of environment variables in the form of
({'ENV_VARIABLE' => 'VALUE'})
. Note: These variables must exist for a command to be run successfully.
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.
interpreter
- Ruby Type: String
The script interpreter to use during code execution.
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.
New in Chef Client 12.21
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, String, Float | Default Value:
3600
The amount of time (in seconds) a command is to wait before timing out.
umask
- Ruby Type: String, Integer
The file mode creation mask, or umask.
user
- Ruby Type: String, Integer
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
oruser@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 property. On Windows only, if this property is specified, the password property must be specified.
Common Resource Functionality
Chef resources include common properties, notifications, and resource guards.
Common Properties
The following properties are common to every resource:
compile_time
Ruby Type: true, false | Default Value:
false
Control the phase during which the resource is run on the node. Set to true to run while the resource collection is being built (the
compile phase
). Set to false to run while Chef Infra Client is configuring the node (theconverge phase
).ignore_failure
Ruby Type: true, false, :quiet | Default Value:
false
Continue running a recipe if a resource fails for any reason.
:quiet
will not display the full stack trace and the recipe will continue to run if a resource fails.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 delay in seconds between retry attempts.
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 anotifies
statement for each resource to be notified.If the referenced resource does not exist, an error is raised. In contrast,
subscribes
will not fail if the source resource is not found.
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, for each 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.
If the other resource does not exist, the subscription will not raise an
error. Contrast this with the stricter semantics of notifies
, which
will raise an error if the other resource does not exist.
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, for each 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 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 Chef Infra Client to do nothing.
PropertiesThe 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
.
Guard Interpreter
Any resource that passes a string command may also specify the
interpreter that will be used to evaluate that string command. This is
done by using the guard_interpreter
property to specify a
script-based resource.
The guard_interpreter
property may be set to any of the following
values:
:bash
Evaluates a string command using the bash resource.
:batch
Evaluates a string command using the batch resource. Default value (within a batch resource block):
:batch
.:csh
Evaluates a string command using the csh resource.
:default
Default. Executes the default interpreter as identified by Chef Infra Client.
:perl
Evaluates a string command using the perl resource.
:powershell_script
Evaluates a string command using the powershell_script resource. Default value (within a powershell_script resource block):
:powershell_script
.:python
Evaluates a string command using the python resource.
:ruby
Evaluates a string command using the ruby resource.
The guard_interpreter
property is set to :default
by default for the
bash, csh, perl, python, and ruby resources. When
the guard_interpreter
property is set to :default
, not_if
or
only_if
guard statements do not inherit properties that are
defined by the script-based resource.
Warning
The batch and powershell_script resources inherit properties by
default. The guard_interpreter
property is set to :batch
or
:powershell_script
automatically when using a not_if
or only_if
guard statement within a batch or powershell_script resource,
respectively.
bash 'javatooling' do
environment 'JAVA_HOME' => '/usr/lib/java/jdk1.7/home'
code 'java-based-daemon-ctl.sh -start'
not_if 'java-based-daemon-ctl.sh -test-started'
end
and requires adding the environment
property to the not_if
guard
statement so that it may use the JAVA_HOME
path as part of its
evaluation:
bash 'javatooling' do
environment 'JAVA_HOME' => '/usr/lib/java/jdk1.7/home'
code 'java-based-daemon-ctl.sh -start'
not_if 'java-based-daemon-ctl.sh -test-started', :environment => 'JAVA_HOME' => '/usr/lib/java/jdk1.7/home'
end
To inherit properties, add the guard_interpreter
property to the
resource block and set it to the appropriate value:
:bash
for bash:csh
for csh:perl
for perl:python
for python:ruby
for ruby
For example, using the same example as from above, but this time adding
the guard_interpreter
property and setting it to :bash
:
bash 'javatooling' do
guard_interpreter :bash
environment 'JAVA_HOME' => '/usr/lib/java/jdk1.7/home'
code 'java-based-daemon-ctl.sh -start'
not_if 'java-based-daemon-ctl.sh -test-started'
end
The not_if
statement now inherits the environment
property and will
use the JAVA_HOME
path as part of its evaluation.
For example, the following code block will ensure the command is evaluated using the default interpreter as identified by Chef Infra Client:
resource 'name' do
guard_interpreter :default
# code
end
Examples
The following examples demonstrate various approaches for using the script resource in recipes:
Use a named provider to run a script
bash 'install_something' do
user 'root'
cwd '/tmp'
code <<-EOH
wget http://www.example.com/tarball.tar.gz
tar -zxf tarball.tar.gz
cd tarball
./configure
make
make install
EOH
end
Run a script
script 'install_something' do
interpreter 'bash'
user 'root'
cwd '/tmp'
code <<-EOH
wget http://www.example.com/tarball.tar.gz
tar -zxf tarball.tar.gz
cd tarball
./configure
make
make install
EOH
end
or something like:
bash 'openvpn-server-key' do
environment('KEY_CN' => 'server')
code <<-EOF
openssl req -batch -days #{node['openvpn']['key']['expire']} \
-nodes -new -newkey rsa:#{key_size} -keyout #{key_dir}/server.key \
-out #{key_dir}/server.csr -extensions server \
-config #{key_dir}/openssl.cnf
EOF
not_if { File.exist?('#{key_dir}/server.crt') }
end
where code
contains the OpenSSL command to be run. The not_if
property tells Chef Infra Client not to run the command if the file
already exists.
Install a file from a remote location using bash
The following is an example of how to install the foo123
module for
Nginx. This module adds shell-style functionality to an Nginx
configuration file and does the following:
- Declares three variables
- Gets the Nginx file from a remote location
- Installs the file using Bash to the path specified by the
src_filepath
variable
# the following code sample is similar to the ``upload_progress_module``
# recipe in the ``nginx`` cookbook:
# https://github.com/chef-cookbooks/nginx
src_filename = "foo123-nginx-module-v#{
node['nginx']['foo123']['version']
}.tar.gz"
src_filepath = "#{Chef::Config['file_cache_path']}/#{src_filename}"
extract_path = "#{
Chef::Config['file_cache_path']
}/nginx_foo123_module/#{
node['nginx']['foo123']['checksum']
}"
remote_file 'src_filepath' do
source node['nginx']['foo123']['url']
checksum node['nginx']['foo123']['checksum']
owner 'root'
group 'root'
mode '0755'
end
bash 'extract_module' do
cwd ::File.dirname(src_filepath)
code <<-EOH
mkdir -p #{extract_path}
tar xzf #{src_filename} -C #{extract_path}
mv #{extract_path}/*/* #{extract_path}/
EOH
not_if { ::File.exist?(extract_path) }
end
Install an application from git using bash
The following example shows how Bash can be used to install a plug-in
for rbenv named ruby-build
, which is located in git version source
control. First, the application is synchronized, and then Bash changes
its working directory to the location in which ruby-build
is located,
and then runs a command.
git "#{Chef::Config[:file_cache_path]}/ruby-build" do
repository 'git://github.com/sstephenson/ruby-build.git'
revision 'master'
action :sync
end
bash 'install_ruby_build' do
cwd "#{Chef::Config[:file_cache_path]}/ruby-build"
user 'rbenv'
group 'rbenv'
code <<-EOH
./install.sh
EOH
environment 'PREFIX' => '/usr/local'
end
To read more about ruby-build
, see here:
https://github.com/sstephenson/ruby-build.
Store certain settings
The following recipe shows how an attributes file can be used to store
certain settings. An attributes file is located in the attributes/
directory in the same cookbook as the recipe which calls the attributes
file. In this example, the attributes file specifies certain settings
for Python that are then used across all nodes against which this recipe
will run.
Python packages have versions, installation directories, URLs, and checksum files. An attributes file that exists to support this type of recipe would include settings like the following:
default['python']['version'] = '2.7.1'
if python['install_method'] == 'package'
default['python']['prefix_dir'] = '/usr'
else
default['python']['prefix_dir'] = '/usr/local'
end
default['python']['url'] = 'http://www.python.org/ftp/python'
default['python']['checksum'] = '80e387...85fd61'
and then the methods in the recipe may refer to these values. A recipe that is used to install Python will need to do the following:
- Identify each package to be installed (implied in this example, not shown)
- Define variables for the package
version
and theinstall_path
- Get the package from a remote location, but only if the package does not already exist on the target system
- Use the bash resource to install the package on the node, but only when the package is not already installed
# the following code sample comes from the ``oc-nginx`` cookbook on |github|: https://github.com/cookbooks/oc-nginx
version = node['python']['version']
install_path = "#{node['python']['prefix_dir']}/lib/python#{version.split(/(^\d+\.\d+)/)[1]}"
remote_file "#{Chef::Config[:file_cache_path]}/Python-#{version}.tar.bz2" do
source "#{node['python']['url']}/#{version}/Python-#{version}.tar.bz2"
checksum node['python']['checksum']
mode '0755'
not_if { ::File.exist?(install_path) }
end
bash 'build-and-install-python' do
cwd Chef::Config[:file_cache_path]
code <<-EOF
tar -jxvf Python-#{version}.tar.bz2
(cd Python-#{version} && ./configure #{configure_options})
(cd Python-#{version} && make && make install)
EOF
not_if { ::File.exist?(install_path) }
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
script 'mkdir test_dir' do
interpreter "bash"
code "mkdir test_dir"
cwd Chef::Config[:file_cache_path]
user "username"
password "password"
end
# Passing username and domain
script 'mkdir test_dir' do
interpreter "bash"
code "mkdir test_dir"
cwd Chef::Config[:file_cache_path]
domain "domain-name"
user "username"
password "password"
end
# Passing username = 'domain-name\\username'. No domain is passed
script 'mkdir test_dir' do
interpreter "bash"
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
script 'mkdir test_dir' do
interpreter "bash"
code "mkdir test_dir"
cwd Chef::Config[:file_cache_path]
user "username@domain-name"
password "password"
end