launchd

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Use the launchd resource to manage system-wide services (daemons) and per-user services (agents) on the Mac OS X platform.

Syntax

A launchd resource manages system-wide services (daemons) and per-user services (agents) on the Mac OS X platform:

launchd 'call.mom.weekly' do
  program '/Library/scripts/call_mom.sh'
  start_calendar_interval 'Weekday' => 7, 'Hourly' => 10
  time_out 300
end

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

launchd 'name' do
  abandon_process_group      TrueClass, FalseClass
  backup                     Integer, FalseClass
  cookbook                   String
  debug                      TrueClass, FalseClass
  disabled                   TrueClass, FalseClass
  enable_globbing            TrueClass, FalseClass
  enable_transactions        TrueClass, FalseClass
  environment_variables      Hash
  exit_timeout               Integer
  group                      String, Integer
  hard_resource_limits       Hash
  ignore_failure             TrueClass, FalseClass
  inetd_compatibility        Hash
  init_groups                TrueClass, FalseClass
  keep_alive                 TrueClass, FalseClass
  label                      String
  launch_only_once           TrueClass, FalseClass
  limit_load_from_hosts      Array
  limit_load_to_hosts        Array
  limit_load_to_session_type String
  low_priority_io            TrueClass, FalseClass
  mach_services              Hash
  mode                       Integer, String
  nice                       Integer
  notifies                   # see description
  on_demand                  TrueClass, FalseClass
  owner                      Integer, String
  path                       String
  plist_hash                 Hash
  process_type               String
  program                    String
  program_arguments          Array
  provider                   Chef::Provider::Launchd
  queue_directories          Array
  retries                    Integer
  retry_delay                Integer
  root_directory             String
  run_at_load                TrueClass, FalseClass
  sockets                    Hash
  soft_resource_limits       Array
  standard_error_path        String
  standard_in_path           String
  standard_out_path          String
  start_calendar_interval    Hash
  start_interval             Integer
  start_on_mount             TrueClass, FalseClass
  subscribes                 # see description
  throttle_interval          Integer
  time_out                   Integer
  type                       String
  umask                      Integer
  username                   String
  wait_for_debugger          TrueClass, FalseClass
  watch_paths                Array
  working_directory          String
  action                     Symbol # defaults to :create if not specified
end

where

  • launchd is the resource
  • name is the name of the resource block
  • action identifies the steps the chef-client will take to bring the node into the desired state
  • abandon_process_group, backup, cookbook, debug, disabled, enable_globbing, enable_transactions, environment_variables, exit_timeout, group, hard_resource_limits, inetd_compatibility, init_groups, keep_alive, label, launch_only_once, limit_load_from_hosts, limit_load_to_hosts, limit_load_to_session_type, low_priority_io, mach_services, mode, nice, on_demand, owner, path, plist_hash, process_type, program, program_arguments, queue_directories, retries, retry_delay, root_directory, run_at_load, sockets, soft_resource_limits, standard_error_path, standard_in_path, standard_out_path, start_calendar_interval, start_interval, start_on_mount, throttle_interval, time_out, type, umask, username, wait_for_debugger, watch_paths, and working_directory 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:

:create
Default. Create a launchd property list.
:create_if_missing
Create a launchd property list, if it does not already exist.
:delete
Delete a launchd property list. This will unload a daemon or agent, if loaded.
:disable
Disable a launchd property list.
:enable
Create a launchd property list, and then ensure that it is enabled. If a launchd property list already exists, but does not match, updates the property list to match, and then restarts the daemon or agent.

Properties

This resource has the following properties:

backup

Ruby Types: Integer, FalseClass

The number of backups to be kept in /var/chef/backup. Set to false to prevent backups from being kept.

cookbook

Ruby Type: String

The name of the cookbook in which the source files are located.

group

Ruby Types: String, Integer

When launchd is run as the root user, the group to run the job as. If the username property is specified and this property is not, this value is set to the default group for the user.

hash

Ruby Type: Hash

A Hash of key value pairs used to create the launchd property list.

Renamed to plist_hash in Chef Client 12.19.

ignore_failure

Ruby Types: TrueClass, FalseClass

Continue running a recipe if a resource fails for any reason. Default value: false.

label

Ruby Type: String

The unique identifier for the job.

mode

Ruby Types: Integer, String

A quoted 3-5 character string that defines the octal mode. For example: '755', '0755', or 00755. If mode is not specified and if the directory already exists, the existing mode on the directory is used. If mode is not specified, the directory does not exist, and the :create action is specified, the chef-client assumes a mask value of '0777', and then applies the umask for the system on which the directory is to be created to the mask value. For example, if the umask on a system is '022', the chef-client uses the default value of '0755'.

The behavior is different depending on the platform.

UNIX- and Linux-based systems: A quoted 3-5 character string that defines the octal mode that is passed to chmod. For example: '755', '0755', or 00755. If the value is specified as a quoted string, it works exactly as if the chmod command was passed. If the value is specified as an integer, prepend a zero (0) to the value to ensure that it is interpreted as an octal number. For example, to assign read, write, and execute rights for all users, use '0777' or '777'; for the same rights, plus the sticky bit, use 01777 or '1777'.

Microsoft Windows: A quoted 3-5 character string that defines the octal mode that is translated into rights for Microsoft Windows security. For example: '755', '0755', or 00755. Values up to '0777' are allowed (no sticky bits) and mean the same in Microsoft Windows as they do in UNIX, where 4 equals GENERIC_READ, 2 equals GENERIC_WRITE, and 1 equals GENERIC_EXECUTE. This property cannot be used to set :full_control. This property has no effect if not specified, but when it and rights are both specified, the effects are cumulative.

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 notifiy more than one resource; use a notifies 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 very 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
owner

Ruby Types: Integer, String

A string or ID that identifies the group owner by user name, including fully qualified user names such as domain\user or user@domain. If this value is not specified, existing owners remain unchanged and new owner assignments use the current user (when necessary).

path

Ruby Type: String

The path to the directory. Using a fully qualified path is recommended, but is not always required. Default value: the name of the resource block See “Syntax” section above for more information.

plist_hash

Ruby Type: Hash

A Hash of key value pairs used to create the launchd property list.

New in Chef Client 12.19. Was previously named hash in earlier versions.

provider

Ruby Type: Chef::Provider::Launchd

Optional. Explicitly specifies a provider. See “Providers” section below for more information.

retries

Ruby Type: Integer

The number of times to catch exceptions and retry the resource. Default value: 0.

retry_delay

Ruby Type: Integer

The retry delay (in seconds). Default value: 2.

session_type

Ruby Type: String

The type of launchd plist to be created. Possible values: system (default) or user.

source

Ruby Type: String

The path to the launchd property list.

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.

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 very 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
supports

Ruby Type: Array

An array of options for supported mount features. Default value: { :remount => false }.

type

Ruby Type: String

The type of resource. Possible values: daemon (default), agent.

The following resource properties may be used to define keys in the XML property list for a daemon or agent. Please refer to the Apple man page documentation for launchd for more information about these keys:

abandon_process_group

Ruby Types: TrueClass, FalseClass

If a job dies, all remaining processes with the same process ID may be kept running. Set to true to kill all remaining processes.

debug

Ruby Types: TrueClass, FalseClass

Sets the log mask to LOG_DEBUG for this job.

disabled

Ruby Types: TrueClass, FalseClass

Hints to launchctl to not submit this job to launchd. Default value: false.

enable_globbing

Ruby Types: TrueClass, FalseClass

Update program arguments before invocation.

enable_transactions

Ruby Types: TrueClass, FalseClass

Track in-progress transactions; if none, then send the SIGKILL signal.

environment_variables

Ruby Type: Hash

Additional environment variables to set before running a job.

exit_timeout

Ruby Type: Integer

The amount of time (in seconds) launchd waits before sending a SIGKILL signal. Default value: 20.

hard_resource_limits

Ruby Type: Hash

A Hash of resource limits to be imposed on a job.

inetd_compatibility

Ruby Type: Hash

Specifies if a daemon expects to be run as if it were launched from inetd. Set to wait => true to pass standard input, output, and error file descriptors. Set to wait => false to call the accept system call on behalf of the job, and then pass standard input, output, and error file descriptors.

init_groups

Ruby Types: TrueClass, FalseClass

Specify if initgroups is called before running a job. Default value: true (starting with Mac OS X 10.5).

keep_alive

Ruby Types: TrueClass, FalseClass, Hash

Keep a job running continuously (true) or allow demand and conditions on the node to determine if the job keeps running (false). Default value: false.

Hash type was added in Chef client 12.14.

launch_only_once

Ruby Types: TrueClass, FalseClass

Specify if a job can be run only one time. Set this value to true if a job cannot be restarted without a full machine reboot.

limit_load_from_hosts

Ruby Type: Array

An array of hosts to which this configuration file does not apply, i.e. “apply this configuration file to all hosts not specified in this array”.

limit_load_to_hosts

Ruby Type: Array

An array of hosts to which this configuration file applies.

limit_load_to_session_type

Ruby Type: String

The session type to which this configuration file applies.

low_priority_io

Ruby Types: TrueClass, FalseClass

Specify if the kernel on the node should consider this daemon to be low priority during file system I/O.

mach_services

Ruby Type: Hash

Specify services to be registered with the bootstrap subsystem.

nice

Ruby Type: Integer

The program scheduling priority value in the range -20 to 20.

on_demand

Ruby Types: TrueClass, FalseClass

Keep a job alive. Only applies to Mac OS X version 10.4 (and earlier); use keep_alive instead for newer versions.

process_type

Ruby Type: String

The intended purpose of the job: Adaptive, Background, Interactive, or Standard.

program

Ruby Type: String

The first argument of execvp, typically the file name associated with the file to be executed. This value must be specified if program_arguments is not specified, and vice-versa.

program_arguments

Ruby Type: Array

The second argument of execvp. If program is not specified, this property must be specified and will be handled as if it were the first argument.

queue_directories

Ruby Type: Array

An array of non-empty directories which, if any are modified, will cause a job to be started.

root_directory

Ruby Type: String

chroot to this directory, and then run the job.

run_at_load

Ruby Types: TrueClass, FalseClass

Launch a job once (at the time it is loaded). Default value: false.

sockets

Ruby Type: Hash

A Hash of on-demand sockets that notify launchd when a job should be run.

soft_resource_limits

Ruby Type: Array

A Hash of resource limits to be imposed on a job.

standard_error_path

Ruby Type: String

The file to which standard error (stderr) is sent.

standard_in_path

Ruby Type: String

The file to which standard input (stdin) is sent.

standard_out_path

Ruby Type: String

The file to which standard output (stdout) is sent.

start_calendar_interval

Ruby Type: Hash

A Hash (similar to crontab) that defines the calendar frequency at which a job is started. For example: { Minute => "0", Hour => "20", Day => "*", Weekday => "1-5", Month => "*" } will run a job at 8:00 PM every day, Monday through Friday, every month of the year.

start_interval

Ruby Type: Integer

The frequency (in seconds) at which a job is started.

start_on_mount

Ruby Types: TrueClass, FalseClass

Start a job every time a file system is mounted.

throttle_interval

Ruby Type: Integer

The frequency (in seconds) at which jobs are allowed to spawn. Default value: 10.

time_out

Ruby Type: Integer

The amount of time (in seconds) a job may be idle before it times out. If no value is specified, the default timeout value for launchd will be used.

umask

Ruby Type: Integer

A decimal value to pass to umask before running a job.

username

Ruby Type: String

When launchd is run as the root user, the user to run the job as.

wait_for_debugger

Ruby Types: TrueClass, FalseClass

Specify if launchd has a job wait for a debugger to attach before executing code.

watch_paths

Ruby Type: Array

An array of paths which, if any are modified, will cause a job to be started.

working_directory

Ruby Type: String

chdir to this directory, and then run the job.

Examples

The following examples demonstrate various 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.

Create a Launch Daemon from a cookbook file

launchd 'com.chef.every15' do
  source 'com.chef.every15.plist'
end

Create a Launch Daemon using keys

launchd 'call.mom.weekly' do
  program '/Library/scripts/call_mom.sh'
  start_calendar_interval 'Weekday' => 7, 'Hourly' => 10
  time_out 300
end

Remove a Launch Daemon

launchd 'com.chef.every15' do
  action :delete
end