Step towards #5027 -- add Logging#deprication_warning facility

This commit adds a method analogous to Puppet.warn which 1) only logs each
message the first time it is received and 2) only logs the first 100 messages
it receives.  Messages are logged via warn.

This could easily be made more flexible by making the hard limit and effective
log level user settable, if desired.

2 files changed, 36 insertions, 0 deletions

diff --git a/lib/puppet/util/logging.rb b/lib/puppet/util/logging.rb
index bc52b17f0..b6845b8fa 100644
--- a/lib/puppet/util/logging.rb
+++ b/lib/puppet/util/logging.rb
@@ -15,6 +15,17 @@ module Puppet::Util::Logging
     end
   end
 
+  def deprication_warning(message)
+    $deprication_warnings ||= Hash.new(0)
+    if $deprication_warnings.length < 100 and ($deprication_warnings[message] += 1) == 1
+      warn message
+    end
+  end
+
+  def clear_deprication_warnings
+    $deprication_warnings.clear if $deprication_warnings
+  end
+
   private
 
   def is_resource?
diff --git a/spec/unit/util/logging_spec.rb b/spec/unit/util/logging_spec.rb
index edc88f115..1585c3e64 100755
--- a/spec/unit/util/logging_spec.rb
+++ b/spec/unit/util/logging_spec.rb
@@ -92,4 +92,29 @@ describe Puppet::Util::Logging do
       end
     end
   end
+
+  describe "when sending a deprication warning" do
+    before do
+      @logger.clear_deprication_warnings
+    end
+
+    it "should the message with warn" do
+      @logger.expects(:warn).with('foo')
+      @logger.deprication_warning 'foo'
+    end
+
+    it "should only log each unique message once" do
+      @logger.expects(:warn).with('foo').once
+      5.times { @logger.deprication_warning 'foo' }
+    end
+
+    it "should only log the first 100 messages" do
+      (1..100).each { |i|
+          @logger.expects(:warn).with(i).once
+          @logger.deprication_warning i
+      }
+      @logger.expects(:warn).with(101).never
+      @logger.deprication_warning 101
+    end
+  end
 end