class Chef::Resource::File::Verification

See RFC 027 for a full specification

File verifications allow user-supplied commands a means of preventing file resource content deploys. Their intended use is to verify the contents of a temporary file before it is deployed onto the system.

Similar to not_if and only_if, file verifications can take a ruby block, which will be called, or a string, which will be executed as a Shell command.

Additonally, Chef or third-party verifications can ship “registered verifications” that the user can use by specifying a :symbol as the command name.

To create a registered verification, create a class that inherits from Chef::Resource::File::Verification and use the provides class method to give it name. Registered verifications are expected to supply a verify instance method that takes 2 arguments.

Example: class Chef

class Resource
  class File::Verification::Foo < Chef::Resource::File::Verification
    provides :noop
    def verify(path, opts)
      #yolo
      true
    end
  end
end

end

Public Class Methods

lookup(name) click to toggle source
# File lib/chef/resource/file/verification.rb, line 75
def self.lookup(name)
  c = descendants.find { |d| d.provides?(name) }
  if c.nil?
    raise Chef::Exceptions::VerificationNotFound.new "No file verification for #{name} found."
  end
  c
end
new(parent_resource, command, opts, &block) click to toggle source
# File lib/chef/resource/file/verification.rb, line 87
def initialize(parent_resource, command, opts, &block)
  @command, @command_opts = command, opts
  @block = block
  @parent_resource = parent_resource
end
provides(name) click to toggle source
# File lib/chef/resource/file/verification.rb, line 67
def self.provides(name)
  @provides = name
end
provides?(name) click to toggle source
# File lib/chef/resource/file/verification.rb, line 71
def self.provides?(name)
  @provides == name
end

Public Instance Methods

logger() click to toggle source
# File lib/chef/resource/file/verification.rb, line 83
def logger
  @parent_resource.logger
end
to_s() click to toggle source
# File lib/chef/resource/file/verification.rb, line 127
def to_s
  if @block
    "<Proc>"
  elsif @command.is_a?(Symbol)
    "#{@command.inspect} (#{Chef::Resource::File::Verification.lookup(@command).name})"
  elsif @command.is_a?(String)
    @command
  end
end
verify(path, opts = {}) click to toggle source
# File lib/chef/resource/file/verification.rb, line 93
def verify(path, opts = {})
  logger.trace("Running verification[#{self}] on #{path}")
  if @block
    verify_block(path, opts)
  elsif @command.is_a?(Symbol)
    verify_registered_verification(path, opts)
  elsif @command.is_a?(String)
    verify_command(path, opts)
  end
end
verify_block(path, opts) click to toggle source

opts is currently unused, but included in the API to support future extensions

# File lib/chef/resource/file/verification.rb, line 106
def verify_block(path, opts)
  @block.call(path)
end
verify_command(path, opts) click to toggle source

We reuse Chef::GuardInterpreter in order to support the same set of options that the not_if/only_if blocks do

# File lib/chef/resource/file/verification.rb, line 112
def verify_command(path, opts)
  if @command.include?("%{file}")
    raise ArgumentError, "The %{file} expansion for verify commands has been removed. Please use %{path} instead."
  end
  command = @command % { path: path }
  interpreter = Chef::GuardInterpreter.for_resource(@parent_resource, command, @command_opts)
  interpreter.evaluate
end
verify_registered_verification(path, opts) click to toggle source
# File lib/chef/resource/file/verification.rb, line 121
def verify_registered_verification(path, opts)
  verification_class = Chef::Resource::File::Verification.lookup(@command)
  v = verification_class.new(@parent_resource, @command, @command_opts, &@block)
  v.verify(path, opts)
end