Add new file_line option append_on_no_match

Author: ripclawffb

README.markdown

@@ -104,6 +104,18 @@ Match Example:
 
 In this code example, `match` looks for a line beginning with export followed by HTTP_PROXY and replaces it with the value in line.
 
+Match Example:
+
+    file_line { 'bashrc_proxy':
+      ensure             => present,
+      path               => '/etc/bashrc',
+      line               => 'export HTTP_PROXY=http://squid.puppetlabs.vm:3128',
+      match              => '^export\ HTTP_PROXY\=',
+      append_on_no_match => false,
+    }
+
+In this code example, `match` looks for a line beginning with export followed by HTTP_PROXY and replaces it with the value in line. If a match is not found, then no changes are made to the file.
+
 Match Example With `ensure => absent`:
 
     file_line { 'bashrc_proxy':
@@ -1526,7 +1538,7 @@ The deprecation messages you get can vary, depending on the modules and data tha
 
 The `validate_legacy` function helps you move from Puppet 3 style validation to Puppet 4 validation without breaking functionality your module's users depend on.
 
-Moving to Puppet 4 type validation allows much better defined type checking using [data types](https://docs.puppet.com/puppet/latest/reference/lang_data.html). Many of Puppet 3's `validate_*` functions have surprising holes in their validation. For example, [validate_numeric](#validate_numeric) allows not only numbers, but also arrays of numbers or strings that look like numbers, without giving you any control over the specifics. 
+Moving to Puppet 4 type validation allows much better defined type checking using [data types](https://docs.puppet.com/puppet/latest/reference/lang_data.html). Many of Puppet 3's `validate_*` functions have surprising holes in their validation. For example, [validate_numeric](#validate_numeric) allows not only numbers, but also arrays of numbers or strings that look like numbers, without giving you any control over the specifics.
 
 For each parameter of your classes and defined types, choose a new Puppet 4 data type to use. In most cases, the new data type allows a different set of values than the original `validate_*` function. The situation then looks like this:
 

lib/puppet/provider/file_line/ruby.rb

@@ -2,6 +2,8 @@
   def exists?
     if resource[:replace].to_s != 'true' and count_matches(match_regex) > 0
       true
+    elsif resource[:append_on_no_match].to_s == 'false' and count_matches(match_regex) == 0
+      true
     else
       lines.find do |line|
         if resource[:ensure].to_s == 'absent' and resource[:match_for_absence].to_s == 'true'

lib/puppet/type/file_line.rb

@@ -107,6 +107,12 @@
     defaultto true
   end
 
+  newparam(:append_on_no_match) do
+    desc 'If true, append line if match is not found. If false, do not append line if a match is not found'
+    newvalues(true, false)
+    defaultto true
+  end
+
   # Autorequire the file resource if it's being managed
   autorequire(:file) do
     self[:path]

spec/unit/puppet/provider/file_line/ruby_spec.rb

@@ -174,6 +174,24 @@
         @provider.create
         expect(File.read(@tmpfile).chomp).to eql("foo1\nfoo = bar\nfoo2")
       end
+
+      it 'should not add line after no matches found' do
+        @resource = Puppet::Type::File_line.new(
+          {
+            :name               => 'foo',
+            :path               => @tmpfile,
+            :line               => 'inserted = line',
+            :match              => '^foo3$',
+            :append_on_no_match => false,
+          }
+        )
+        @provider = provider_class.new(@resource)
+        File.open(@tmpfile, 'w') do |fh|
+          fh.write("foo1\nfoo = blah\nfoo2\nfoo = baz")
+        end
+        expect(@provider.exists?).to be true
+        expect(File.read(@tmpfile).chomp).to eql("foo1\nfoo = blah\nfoo2\nfoo = baz")
+      end
     end
 
     describe 'using after' do