perl Resource
This page is generated from the Chef Infra Client source code.To suggest a change, edit the perl.rb file and submit a pull request to the Chef Infra Client repository.
Use the perl resource to execute scripts using the Perl interpreter. 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.
Syntax
A perl resource block executes scripts Perl:
perl 'hello world' do
code <<-EOH
print "Hello world! From Chef and Perl.";
EOH
end
where:
code
specifies the command to run.
where:
code
specifies the command to run
The full syntax for all of the properties that are available to the perl resource is:
perl 'name' do
code String
command String, Array # default value: 'name' unless specified
creates String
cwd String
default_env true, false # default value: false
domain String
elevated true, false # default value: false
environment Hash
flags String
group String, Integer
input String
interpreter String
live_stream true, false # default value: false
login true, false # default value: false
password String
returns Integer, Array # default value: 0
timeout Integer, String, Float # default value: 3600
user String, Integer
action Symbol # defaults to :run if not specified
end
where:
perl
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
,environment
,flags
,group
,ignore_failure
,notifies
,returns
,subscribes
,timeout
,user
, andumask
are the properties available to this resource.
Actions
The perl 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 perl 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.
environment
- Ruby Type: Hash
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
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.
ignore_failure
- Ruby Type: true, false
Continue running a recipe if a resource fails for any reason. (default false)
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
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.
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.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
timeout
- Ruby Type: Integer, String, Float | Default Value:
3600
The amount of time (in seconds) a command is to wait before timing out.
user
- Ruby Type: String, Integer
The user name or user ID that should be changed before running a command.
umask
- Ruby Type: String, Integer
The file mode creation mask, or umask.
Common Resource Functionality
Chef resources include common properties, notifications, and resource guards.
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
.
Examples
This resource does not have any examples.