type augeas: add 'incl' and 'lens' parameters

These parameters allow loading a file anywhere on the filesystem; using
them also greatly speeds up processing the resource.

  * lib/puppet/type/augeas.rb: add 'incl' and 'lens' parameters; change
    default for 'context' when 'incl' is given.
  * lib/puppet/provider/augeas/augeas.rb: when 'lens' and 'incl' are given,
    only load that file
  * spec/unit/type/augeas.rb: check that constraints on new parameters are
    enforced

This fixes ticket #2694

2 files changed, 31 insertions, 3 deletions

diff --git a/lib/puppet/provider/augeas/augeas.rb b/lib/puppet/provider/augeas/augeas.rb
index a645fbe8a..78be1d79e 100644
--- a/lib/puppet/provider/augeas/augeas.rb
+++ b/lib/puppet/provider/augeas/augeas.rb
@@ -133,6 +133,7 @@ Puppet::Type.type(:augeas).provide(:augeas) do
         unless @aug
             flags = Augeas::NONE
             flags = Augeas::TYPE_CHECK if resource[:type_check] == :true
+            flags |= Augeas::NO_MODL_AUTOLOAD if resource[:incl]
             root = resource[:root]
             load_path = resource[:load_path]
             debug("Opening augeas with root #{root}, lens path #{load_path}, flags #{flags}")
@@ -141,6 +142,12 @@ Puppet::Type.type(:augeas).provide(:augeas) do
             if get_augeas_version >= "0.3.6"
                 debug("Augeas version #{get_augeas_version} is installed")
             end
+
+            if resource[:incl]
+                aug.set("/augeas/load/Xfm/lens", resource[:lens])
+                aug.set("/augeas/load/Xfm/incl", resource[:incl])
+                aug.load
+            end
         end
         @aug
     end
diff --git a/lib/puppet/type/augeas.rb b/lib/puppet/type/augeas.rb
index 4ae3f06e1..b8d08bb81 100644
--- a/lib/puppet/type/augeas.rb
+++ b/lib/puppet/type/augeas.rb
@@ -58,10 +58,15 @@ Puppet::Type.newtype(:augeas) do
     end
 
     newparam (:context) do
-        desc "Optional context path. This value is pre-pended to the paths of all changes if the
-              path is relative. So a path specified as /files/foo will not be prepended with the
-              context whild files/foo will be prepended"
+        desc "Optional context path. This value is prepended to the paths of all changes if the path is relative. If INCL is set, defaults to '/files' + INCL, otherwise the empty string"
         defaultto ""
+        munge do |value|
+            if value.empty? and resource[:incl]
+                "/files" + resource[:incl]
+            else
+                value
+            end
+        end
     end
 
     newparam (:onlyif) do
@@ -129,6 +134,22 @@ Puppet::Type.newtype(:augeas) do
         defaultto :false
     end
 
+    newparam(:lens) do
+        desc "Use a specific lens, e.g. 'Hosts.lns'. When this parameter is set, you must also set the incl parameter to indicate which file to load. Only that file will be loaded, which greatly speeds up execution of the type"
+    end
+
+    newparam(:incl) do
+        desc "Load only a specific file, e.g. '/etc/hosts'.  When this parameter is set, you must also set the lens parameter to indicate which lens to use."
+    end
+
+    validate do
+        has_lens = !self[:lens].nil?
+        has_incl = !self[:incl].nil?
+        if has_lens != has_incl
+            self.fail "You must specify both the lens and incl parameters, or neither"
+        end
+    end
+
     # This is the acutal meat of the code. It forces
     # augeas to be run and fails or not based on the augeas return
     # code.