Add the default value to the "loadyaml" function

This value will be returned if the is no file
to load or a file could not be parsed.
It's similar to the "parseyaml" function's
default value.

Add the "loadjson" function too

Author: Dmitry Ilyin

README.markdown

@@ -660,12 +660,38 @@ Returns the keys of a hash as an array. *Type*: rvalue.
 
 #### `loadyaml`
 
-Loads a YAML file containing an array, string, or hash, and returns the data in the corresponding native data type. For example:
+Loads a YAML file containing an array, string, or hash, and returns the data in the corresponding native data type.
+For example:
 
   ~~~
   $myhash = loadyaml('/etc/puppet/data/myhash.yaml')
   ~~~
 
+The second parameter will be returned if the file was not found or could not be parsed.
+For example:
+
+  ~~~
+  $myhash = loadyaml('no-file.yaml', {'default'=>'value'})
+  ~~~
+
+*Type*: rvalue.
+
+#### `loadjson`
+
+Loads a JSON file containing an array, string, or hash, and returns the data in the corresponding native data type.
+For example:
+
+  ~~~
+  $myhash = loadjson('/etc/puppet/data/myhash.json')
+  ~~~
+
+The second parameter will be returned if the file was not found or could not be parsed.
+For example:
+
+  ~~~
+  $myhash = loadjson('no-file.json', {'default'=>'value'})
+  ~~~
+
 *Type*: rvalue.
 
 #### `load_module_metadata`

lib/puppet/parser/functions/loadjson.rb

@@ -0,0 +1,34 @@
+module Puppet::Parser::Functions
+  newfunction(:loadjson, :type => :rvalue, :arity => -2, :doc => <<-'ENDHEREDOC') do |args|
+Load a JSON file containing an array, string, or hash, and return the data
+in the corresponding native data type.
+The second parameter is the default value. It will be returned if the file
+was not found or could not be parsed.
+
+For example:
+
+    $myhash = loadjson('/etc/puppet/data/myhash.json')
+    $myhash = loadjson('no-file.json', {'default' => 'value'})
+  ENDHEREDOC
+
+    raise ArgumentError, 'Wrong number of arguments. 1 or 2 arguments should be provided.' unless args.length >= 1
+
+    if File.exists?(args[0])
+      begin
+        content = File.read(args[0])
+        PSON::load(content) || args[1]
+      rescue Exception => e
+        if args[1]
+          args[1]
+        else
+          raise e
+        end
+      end
+    else
+      warning("Can't load '#{args[0]}' File does not exist!")
+      args[1]
+    end
+
+  end
+
+end

lib/puppet/parser/functions/loadyaml.rb

@@ -1,23 +1,32 @@
 module Puppet::Parser::Functions
+  newfunction(:loadyaml, :type => :rvalue, :arity => -2, :doc => <<-'ENDHEREDOC') do |args|
+Load a YAML file containing an array, string, or hash, and return the data
+in the corresponding native data type.
+The second parameter is the default value. It will be returned if the file
+was not found or could not be parsed.
 
-  newfunction(:loadyaml, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args|
-    Load a YAML file containing an array, string, or hash, and return the data
-    in the corresponding native data type.
+For example:
 
-    For example:
+    $myhash = loadyaml('/etc/puppet/data/myhash.yaml')
+    $myhash = loadyaml('no-file.yaml', {'default' => 'value'})
+  ENDHEREDOC
 
-        $myhash = loadyaml('/etc/puppet/data/myhash.yaml')
-    ENDHEREDOC
+    raise ArgumentError, 'Wrong number of arguments. 1 or 2 arguments should be provided.' unless args.length >= 1
+    require 'yaml'
 
-    unless args.length == 1
-      raise Puppet::ParseError, ("loadyaml(): wrong number of arguments (#{args.length}; must be 1)")
-    end
-
-    if File.exists?(args[0]) then
-      YAML.load_file(args[0])
+    if File.exists?(args[0])
+      begin
+        YAML::load_file(args[0]) || args[1]
+      rescue Exception => e
+        if args[1]
+          args[1]
+        else
+          raise e
+        end
+      end
     else
-      warning("Can't load " + args[0] + ". File does not exist!")
-      nil
+      warning("Can't load '#{args[0]}' File does not exist!")
+      args[1]
     end
 
   end

spec/acceptance/loadjson_spec.rb

@@ -0,0 +1,52 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper_acceptance'
+
+tmpdir = default.tmpdir('stdlib')
+
+describe 'loadjson function', :unless => UNSUPPORTED_PLATFORMS.include?(fact('operatingsystem')) do
+  describe 'success' do
+    it 'loadjsons array of values' do
+      shell("echo '{\"aaa\":1,\"bbb\":2,\"ccc\":3,\"ddd\":4}' > #{tmpdir}/testjson.json")
+      pp = <<-EOS
+      $o = loadjson('#{tmpdir}/testjson.json')
+      notice(inline_template('loadjson[aaa] is <%= @o["aaa"].inspect %>'))
+      notice(inline_template('loadjson[bbb] is <%= @o["bbb"].inspect %>'))
+      notice(inline_template('loadjson[ccc] is <%= @o["ccc"].inspect %>'))
+      notice(inline_template('loadjson[ddd] is <%= @o["ddd"].inspect %>'))
+      EOS
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/loadjson\[aaa\] is 1/)
+        expect(r.stdout).to match(/loadjson\[bbb\] is 2/)
+        expect(r.stdout).to match(/loadjson\[ccc\] is 3/)
+        expect(r.stdout).to match(/loadjson\[ddd\] is 4/)
+      end
+    end
+
+    it 'returns the default value if there is no file to load' do
+      pp = <<-EOS
+      $o = loadjson('#{tmpdir}/no-file.json', {'default' => 'value'})
+      notice(inline_template('loadjson[default] is <%= @o["default"].inspect %>'))
+      EOS
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/loadjson\[default\] is "value"/)
+      end
+    end
+
+    it 'returns the default value if the file was parsed with an error' do
+      shell("echo '!' > #{tmpdir}/testjson.json")
+      pp = <<-EOS
+      $o = loadjson('#{tmpdir}/testjson.json', {'default' => 'value'})
+      notice(inline_template('loadjson[default] is <%= @o["default"].inspect %>'))
+      EOS
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/loadjson\[default\] is "value"/)
+      end
+    end
+  end
+  describe 'failure' do
+    it 'fails with no arguments'
+  end
+end

spec/acceptance/loadyaml_spec.rb

@@ -26,6 +26,29 @@
         expect(r.stdout).to match(/loadyaml\[ddd\] is 4/)
       end
     end
+
+    it 'returns the default value if there is no file to load' do
+      pp = <<-EOS
+      $o = loadyaml('#{tmpdir}/no-file.yaml', {'default' => 'value'})
+      notice(inline_template('loadyaml[default] is <%= @o["default"].inspect %>'))
+      EOS
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/loadyaml\[default\] is "value"/)
+      end
+    end
+
+    it 'returns the default value if the file was parsed with an error' do
+      shell("echo '!' > #{tmpdir}/testyaml.yaml")
+      pp = <<-EOS
+      $o = loadyaml('#{tmpdir}/testyaml.yaml', {'default' => 'value'})
+      notice(inline_template('loadyaml[default] is <%= @o["default"].inspect %>'))
+      EOS
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/loadyaml\[default\] is "value"/)
+      end
+    end
   end
   describe 'failure' do
     it 'fails with no arguments'

spec/functions/loadjson_spec.rb

@@ -0,0 +1,38 @@
+require 'spec_helper'
+
+describe 'loadjson' do
+  it { is_expected.not_to eq(nil) }
+  it { is_expected.to run.with_params().and_raise_error(ArgumentError, /wrong number of arguments/i) }
+
+  context 'when a non-existing file is specified' do
+    let(:filename) { '/tmp/doesnotexist' }
+    before {
+      File.expects(:exists?).with(filename).returns(false).once
+      PSON.expects(:load).never
+    }
+    it { is_expected.to run.with_params(filename, {'default' => 'value'}).and_return({'default' => 'value'}) }
+  end
+
+  context 'when an existing file is specified' do
+    let(:filename) { '/tmp/doesexist' }
+    let(:data) { { 'key' => 'value' } }
+    let(:json) { '{"key":"value"}' }
+    before {
+      File.expects(:exists?).with(filename).returns(true).once
+      File.expects(:read).with(filename).returns(json).once
+      PSON.expects(:load).with(json).returns(data).once
+    }
+    it { is_expected.to run.with_params(filename).and_return(data) }
+  end
+
+  context 'when the file could not be parsed' do
+    let(:filename) { '/tmp/doesexist' }
+    let(:json) { '{"key":"value"}' }
+    before {
+      File.expects(:exists?).with(filename).returns(true).once
+      File.expects(:read).with(filename).returns(json).once
+      PSON.stubs(:load).with(json).once.raises StandardError, 'Something terrible have happened!'
+    }
+    it { is_expected.to run.with_params(filename, {'default' => 'value'}).and_return({'default' => 'value'}) }
+  end
+end

spec/functions/loadyaml_spec.rb

@@ -2,16 +2,17 @@
 
 describe 'loadyaml' do
   it { is_expected.not_to eq(nil) }
-  it { is_expected.to run.with_params().and_raise_error(Puppet::ParseError, /wrong number of arguments/i) }
-  it { is_expected.to run.with_params('', '').and_raise_error(Puppet::ParseError, /wrong number of arguments/i) }
+  it { is_expected.to run.with_params().and_raise_error(ArgumentError, /wrong number of arguments/i) }
+
   context 'when a non-existing file is specified' do
     let(:filename) { '/tmp/doesnotexist' }
     before {
       File.expects(:exists?).with(filename).returns(false).once
       YAML.expects(:load_file).never
     }
-    it { is_expected.to run.with_params(filename).and_return(nil) }
+    it { is_expected.to run.with_params(filename, {'default' => 'value'}).and_return({'default' => 'value'}) }
   end
+
   context 'when an existing file is specified' do
     let(:filename) { '/tmp/doesexist' }
     let(:data) { { 'key' => 'value' } }
@@ -21,4 +22,13 @@
     }
     it { is_expected.to run.with_params(filename).and_return(data) }
   end
+
+  context 'when the file could not be parsed' do
+    let(:filename) { '/tmp/doesexist' }
+    before {
+      File.expects(:exists?).with(filename).returns(true).once
+      YAML.stubs(:load_file).with(filename).once.raises StandardError, 'Something terrible have happened!'
+    }
+    it { is_expected.to run.with_params(filename, {'default' => 'value'}).and_return({'default' => 'value'}) }
+  end
 end