Add support for a 'match' parameter to file_line

This commit adds a new parameter called "match"
to the file_line resource type, and support for
this new parameter to the corresponding ruby
provider.

This parameter is optional; file_line should work
just as before if you do not specify this parameter...
so this change should be backwards-compatible.

If you do specify the parameter, it is treated
as a regular expression that should be used when
looking through the file for a line.  This allows
you to do things like find a line that begins with
a certain prefix (e.g., "foo=.*"), and *replace*
the existing line with the line you specify in your
"line" parameter.  Without this capability, if you
already had a line "foo=bar" in your file and your
"line" parameter was set to "foo=baz", you'd end up
with *both* lines in the final file.  In many cases
this is undesirable.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/puppet/type/file_line.rb b/lib/puppet/type/file_line.rb
index f6fe1d0..6b35902 100644
--- a/lib/puppet/type/file_line.rb
+++ b/lib/puppet/type/file_line.rb
@@ -32,6 +32,11 @@ Puppet::Type.newtype(:file_line) do
     desc 'An arbitrary name used as the identity of the resource.'
   end
 
+  newparam(:match) do
+    desc 'An optional regular expression to run against existing lines in the file;\n' +
+        'if a match is found, we replace that line rather than adding a new line.'
+  end
+
   newparam(:line) do
     desc 'The line to be appended to the file located by the path parameter.'
   end
@@ -49,5 +54,12 @@ Puppet::Type.newtype(:file_line) do
     unless self[:line] and self[:path]
       raise(Puppet::Error, "Both line and path are required attributes")
     end
+
+    if (self[:match])
+      unless Regexp.new(self[:match]).match(self[:line])
+        raise(Puppet::Error, "When providing a 'match' parameter, the value must be a regex that matches against the value of your 'line' parameter")
+      end
+    end
+
   end
 end