module Chef::DSL::DeclareResource

Public Instance Methods

build_resource(type, name, created_at: nil, run_context: self.run_context, enclosing_provider: nil, &resource_attrs_block) click to toggle source

Instantiate a resource of the given type with the given name and attributes as given in the resource_attrs_block.

The resource is NOT added to the resource collection.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param created_at [String] The caller of the resource. Use `caller`

to get the caller of your function.  Defaults to the caller of this
function.

@param run_context [Chef::RunContext] the run_context of the resource collection to operate on @param resource_attrs_block A block that lets you set attributes of the

resource (it is instance_eval'd on the resource instance).

@return [Chef::Resource] The new resource.

@example

build_resource(:file, '/x/y.txt', caller[0]) do
  action :delete
end
# File lib/chef/dsl/declare_resource.rb, line 292
def build_resource(type, name, created_at: nil, run_context: self.run_context, enclosing_provider: nil, &resource_attrs_block)
  created_at ||= caller[0]

  # this needs to be lazy in order to avoid circular dependencies since ResourceBuilder
  # will requires the entire provider+resolver universe
  require_relative "../resource_builder" unless defined?(Chef::ResourceBuilder)

  enclosing_provider ||= self if is_a?(Chef::Provider)

  nr = new_resource if defined?(new_resource)

  Chef::ResourceBuilder.new(
    type:                type,
    name:                name,
    created_at:          created_at,
    params:              @params,
    run_context:         run_context,
    cookbook_name:       cookbook_name,
    recipe_name:         recipe_name,
    enclosing_provider:  enclosing_provider,
    new_resource:        nr
  ).build(&resource_attrs_block)
end
declare_resource(type, name, created_at: nil, run_context: self.run_context, enclosing_provider: nil, &resource_attrs_block) click to toggle source

Instantiates a resource (via build_resource), then adds it to the resource collection. Note that resource classes are looked up directly, so this will create the resource you intended even if the method name corresponding to that resource has been overridden.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param created_at [String] The caller of the resource. Use `caller`

to get the caller of your function.  Defaults to the caller of this
function.

@param run_context [Chef::RunContext] the run_context of the resource collection to operate on @param resource_attrs_block A block that lets you set attributes of the

resource (it is instance_eval'd on the resource instance).

@return [Chef::Resource] The new resource.

@example

declare_resource(:file, '/x/y.txt', caller[0]) do
  action :delete
end
# Equivalent to
file '/x/y.txt' do
  action :delete
end
# File lib/chef/dsl/declare_resource.rb, line 262
def declare_resource(type, name, created_at: nil, run_context: self.run_context, enclosing_provider: nil, &resource_attrs_block)
  created_at ||= caller[0]

  resource = build_resource(type, name, created_at: created_at, enclosing_provider: enclosing_provider, &resource_attrs_block)

  run_context.resource_collection.insert(resource, resource_type: resource.declared_type, instance_name: resource.name)
  resource
end
delete_resource(type, name, run_context: self.run_context) click to toggle source

Lookup a resource in the resource collection by name and delete it. Returns nil if the resource is not found and should not fail.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param run_context [Chef::RunContext] the run_context of the resource collection to operate on

@return [Chef::Resource] The resource

@example

delete_resource(:template, '/x/y.txt')
# File lib/chef/dsl/declare_resource.rb, line 98
def delete_resource(type, name, run_context: self.run_context)
  delete_resource!(type, name, run_context: run_context)
rescue Chef::Exceptions::ResourceNotFound
  nil
end
delete_resource!(type, name, run_context: self.run_context) click to toggle source

Lookup a resource in the resource collection by name and delete it. This will raise Chef::Exceptions::ResourceNotFound if the resource is not found.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param run_context [Chef::RunContext] the run_context of the resource collection to operate on

@return [Chef::Resource] The resource

@example

delete_resource!(:template, '/x/y.txt')
# File lib/chef/dsl/declare_resource.rb, line 74
def delete_resource!(type, name, run_context: self.run_context)
  run_context.resource_collection.delete("#{type}[#{name}]").tap do |resource|
    # Purge any pending notifications too. This will not raise an exception
    # if there are no notifications.
    if resource
      run_context.before_notification_collection.delete(resource.declared_key)
      run_context.immediate_notification_collection.delete(resource.declared_key)
      run_context.delayed_notification_collection.delete(resource.declared_key)
    end
  end
end
edit_resource(type, name, created_at: nil, run_context: self.run_context, &resource_attrs_block) click to toggle source

Lookup a resource in the resource collection by name. If it exists, return it. If it does not exist, create it. This is a useful function for accumulator patterns. In CRUD terminology this is an “upsert” operation and is used to assert that the resource must exist with the specified properties.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param created_at [String] The caller of the resource. Use `caller`

to get the caller of your function.  Defaults to the caller of this
function.

@param run_context [Chef::RunContext] the run_context of the resource collection to operate on @param resource_attrs_block A block that lets you set attributes of the

resource (it is instance_eval'd on the resource instance).

@return [Chef::Resource] The updated or created resource

@example

resource = edit_resource(:template, '/x/y.txt') do
  source "y.txt.erb"
  variables {}
end
resource.variables.merge!({ home: "/home/clowns"  })
# File lib/chef/dsl/declare_resource.rb, line 156
def edit_resource(type, name, created_at: nil, run_context: self.run_context, &resource_attrs_block)
  edit_resource!(type, name, created_at: created_at, run_context: run_context, &resource_attrs_block)
rescue Chef::Exceptions::ResourceNotFound
  declare_resource(type, name, created_at: created_at, run_context: run_context, &resource_attrs_block)
end
edit_resource!(type, name, created_at: nil, run_context: self.run_context, &resource_attrs_block) click to toggle source

Lookup a resource in the resource collection by name and edit the resource. If the resource is not found this will raise Chef::Exceptions::ResourceNotFound. This is the correct API to use for “chef_rewind” functionality.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param run_context [Chef::RunContext] the run_context of the resource collection to operate on @param resource_attrs_block A block that lets you set attributes of the

resource (it is instance_eval'd on the resource instance).

@return [Chef::Resource] The updated resource

@example

edit_resource!(:template, '/x/y.txt') do
  cookbook_name: cookbook_name
end
# File lib/chef/dsl/declare_resource.rb, line 121
def edit_resource!(type, name, created_at: nil, run_context: self.run_context, &resource_attrs_block)
  resource = find_resource!(type, name, run_context: run_context)
  if resource_attrs_block
    if defined?(new_resource)
      resource.instance_exec(new_resource, &resource_attrs_block)
    else
      resource.instance_exec(&resource_attrs_block)
    end
  end
  resource
end
find_resource(type, name, created_at: nil, run_context: self.run_context, &resource_attrs_block) click to toggle source

Lookup a resource in the resource collection by name. If the resource is not found the will be no exception raised and the call will return nil. If a block is given and no resource is found it will create the resource using the block, if the resource is found then the block will not be applied. The block version is similar to create_if_missing

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param run_context [Chef::RunContext] the run_context of the resource collection to operate on

@return [Chef::Resource] The updated resource

@example

if ( find_resource(:template, '/x/y.txt') )
  # do something
else
  # don't worry about the error
end

@example

# this API can be used to return a resource from an outer run context, and will only create
# an action :nothing service if one does not already exist.
resource = with_run_context(:root) do
  find_resource(:service, 'whatever') do
    action :nothing
  end
end
# File lib/chef/dsl/declare_resource.rb, line 229
def find_resource(type, name, created_at: nil, run_context: self.run_context, &resource_attrs_block)
  find_resource!(type, name, run_context: run_context)
rescue Chef::Exceptions::ResourceNotFound
  if resource_attrs_block
    declare_resource(type, name, created_at: created_at, run_context: run_context, &resource_attrs_block)
  end # returns nil otherwise
end
find_resource!(type, name, run_context: self.run_context) click to toggle source

Lookup a resource in the resource collection by name. If the resource is not found this will raise Chef::Exceptions::ResourceNotFound. This API is identical to the resources() call and while it is a synonym it is not intended to deprecate that call.

@param type [Symbol] The type of resource (e.g. `:file` or `:package`) @param name [String] The name of the resource (e.g. '/x/y.txt' or 'apache2') @param run_context [Chef::RunContext] the run_context of the resource collection to operate on

@return [Chef::Resource] The updated resource

@example

resource = find_resource!(:template, '/x/y.txt')
# File lib/chef/dsl/declare_resource.rb, line 196
def find_resource!(type, name, run_context: self.run_context)
  raise ArgumentError, "find_resource! does not take a block" if block_given?

  run_context.resource_collection.find(type => name)
end
resources(*args) click to toggle source

Find existing resources by searching the list of existing resources. Possible forms are:

find(:file => "foobar")
find(:file => [ "foobar", "baz" ])
find("file[foobar]", "file[baz]")
find("file[foobar,baz]")

Calls `run_context.resource_collection.find(*args)`

The is backcompat API, the use of find_resource, below, is encouraged.

@return the matching resource, or an Array of matching resources.

@raise ArgumentError if you feed it bad lookup information @raise RuntimeError if it can't find the resources you are looking for.

# File lib/chef/dsl/declare_resource.rb, line 179
def resources(*args)
  run_context.resource_collection.find(*args)
end
with_run_context(rc) { || ... } click to toggle source

Helper for switching run_contexts. Allows for using :parent or :root in place of passing the run_context. Executes the block in the run_context. Returns the return value of the passed block.

@param rc [Chef::RunContext,Symbol] Either :root, :parent or a Chef::RunContext

@return return value of the block

@example

# creates/returns a 'service[foo]' resource in the root run_context
resource = with_run_context(:root)
  edit_resource(:service, "foo") do
    action :nothing
  end
end
# File lib/chef/dsl/declare_resource.rb, line 42
def with_run_context(rc)
  raise ArgumentError, "with_run_context is useless without a block" unless block_given?

  old_run_context = @run_context
  @run_context =
    case rc
    when Chef::RunContext
      rc
    when :root
      run_context.root_run_context
    when :parent
      run_context.parent_run_context
    else
      raise ArgumentError, "bad argument to run_context helper, must be :root, :parent, or a Chef::RunContext"
    end
  yield
ensure
  @run_context = old_run_context
end