Porting functions to the modern Puppet 4.x API

lib/puppet/functions/augeas/augeas.rb

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+# This is an autogenerated function, ported from the original legacy version.
+# It /should work/ as is, but will not have all the benefits of the modern
+# function API. You should see the function docs to learn how to add function
+# signatures for type safety and to document this function using puppet-strings.
+#
+# https://puppet.com/docs/puppet/latest/custom_functions_ruby.html
+#
+# ---- original file header ----
+#
+# augeas.rb
+#
+
+# ---- original file header ----
+#
+# @summary
+#   Modifies a string using Augeas.
+#
+#*Example:*
+#
+#    augeas("proc        /proc   proc    nodev,noexec,nosuid     0       0
+#", 'Fstab.lns', ['rm ./1/opt[3]'])
+#
+#Would result in:
+#
+#    "proc        /proc   proc    nodev,noexec     0       0
+#"
+#
+#
+Puppet::Functions.create_function(:'augeas::augeas') do
+  # @param arguments
+  #   The original array of arguments. Port this to individually managed params
+  #   to get the full benefit of the modern function API.
+  #
+  # @return [Data type]
+  #   Describe what the function returns here
+  #
+  dispatch :default_impl do
+    # Call the method named 'default_impl' when this is matched
+    # Port this to match individual params for better type safety
+    repeated_param 'Any', :arguments
+  end
+
+
+  def default_impl(*arguments)
+
+    unless Puppet.features.augeas?
+      raise Puppet::ParseError, ('augeas(): this function requires the augeas feature. See http://projects.puppetlabs.com/projects/puppet/wiki/Puppet_Augeas#Pre-requisites for how to activate it.')
+    end
+
+    # Check that 2 arguments have been given ...
+    raise(Puppet::ParseError, 'augeas(): Wrong number of arguments ' +
+      "given (#{arguments.size} for 3)") if arguments.size != 3
+
+    content = arguments[0]
+    lens = arguments[1]
+    changes = arguments[2]
+
+    # Check arguments
+    raise(Puppet::ParseError, 'augeas(): content must be a string') unless content.is_a?(String)
+    raise(Puppet::ParseError, 'augeas(): lens must be a string') unless lens.is_a?(String)
+    raise(Puppet::ParseError, 'augeas(): changes must be an array') unless changes.is_a?(Array)
+
+    require 'augeas'
+    aug = Augeas::open(nil, nil, Augeas::NO_MODL_AUTOLOAD)
+    augeas_version = aug.get('/augeas/version')
+    raise(Puppet::ParseError, 'augeas(): requires Augeas 1.0.0 or greater') unless Puppet::Util::Package.versioncmp(augeas_version, '1.0.0') >= 0
+    raise(Puppet::ParseError, 'augeas(): requires ruby-augeas 0.5.0 or greater') unless aug.methods.include?(:text_store)
+
+    result = nil
+    begin
+      aug.set('/input', content)
+      aug.text_store(lens, '/input', '/store')
+      unless aug.match("/augeas/text/store//error").empty?
+          error = aug.get("/augeas/text/store//error/message")
+          raise Puppet::ParseError, "augeas(): Failed to parse string with lens #{lens}: #{error}"
+      end
+
+      # Apply changes
+      aug.context = '/store'
+      changes.each do |c|
+        r = aug.srun(c)
+        raise Puppet::ParseError, "augeas(): Failed to apply change to tree" unless r and r[0] >= 0
+      end
+      unless aug.text_retrieve(lens, '/input', '/store', '/output')
+        error = aug.get("/augeas/text/store//error/message")
+        raise Puppet::ParseError, "augeas(): Failed to apply changes with lens #{lens}: #{error}"
+      end
+      result = aug.get("/output")
+    ensure
+      aug.close
+    end
+    return result
+
+  end
+end

spec/functions/augeas_augeas_spec.rb

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+require 'spec_helper'
+
+describe 'augeas::augeas' do
+  # without knowing details about the implementation, this is the only test
+  # case that we can autogenerate. You should add more examples below!
+  it { is_expected.not_to eq(nil) }
+
+#################################
+# Below are some example test cases. You may uncomment and modify them to match
+# your needs. Notice that they all expect the base error class of `StandardError`.
+# This is because the autogenerated function uses an untyped array for parameters
+# and relies on your implementation to do the validation. As you convert your
+# function to proper dispatches and typed signatures, you should change the
+# expected error of the argument validation examples to `ArgumentError`.
+#
+# Other error types you might encounter include
+#
+# * StandardError
+# * ArgumentError
+# * Puppet::ParseError
+#
+# Read more about writing function unit tests at https://rspec-puppet.com/documentation/functions/
+#
+#   it 'raises an error if called with no argument' do
+#     is_expected.to run.with_params.and_raise_error(StandardError)
+#   end
+#
+#   it 'raises an error if there is more than 1 arguments' do
+#     is_expected.to run.with_params({ 'foo' => 1 }, 'bar' => 2).and_raise_error(StandardError)
+#   end
+#
+#   it 'raises an error if argument is not the proper type' do
+#     is_expected.to run.with_params('foo').and_raise_error(StandardError)
+#   end
+#
+#   it 'returns the proper output' do
+#     is_expected.to run.with_params(123).and_return('the expected output')
+#   end
+#################################
+
+end