Add Log.warn_oncejk/warn_once

2 files changed, 46 insertions, 3 deletions

diff --git a/lib/mixlib/log.rb b/lib/mixlib/log.rb
index 5ff243d..118c58e 100644
--- a/lib/mixlib/log.rb
+++ b/lib/mixlib/log.rb
@@ -19,6 +19,7 @@
 require 'logger'
 require 'mixlib/log/version'
 require 'mixlib/log/formatter'
+require 'set'
 
 module Mixlib
   module Log
@@ -30,7 +31,7 @@ module Mixlib
 
 
     def reset!
-      @logger, @loggers = nil, nil
+      @logger, @loggers, @warned_from = nil, nil
     end
 
     # An Array of log devices that will be logged to. Defaults to just the default
@@ -116,6 +117,18 @@ module Mixlib
       METHOD_DEFN
     end
 
+    #
+    # Warn the user about something, but only once per caller. Subsequent log
+    # messages are logged at debug level.
+    #
+    def warn_once(msg=nil, &block)
+      if warned_from.add?(caller[0])
+        warn(msg, &block)
+      else
+        debug("WARN: #{msg}", &block)
+      end
+    end
+
     # Define the methods to interrogate the logger for the current log level.
     # Note that we *only* query the default logger (@logger) and not any other
     # loggers that may have been added, even though it is possible to configure
@@ -147,6 +160,10 @@ module Mixlib
 
     private
 
+    def warned_from
+      @warned_from ||= Set.new
+    end
+
     def logger_for(*opts)
       if opts.empty?
         Logger.new(STDOUT)
diff --git a/spec/mixlib/log_spec.rb b/spec/mixlib/log_spec.rb
index 640ae81..813cc6e 100644
--- a/spec/mixlib/log_spec.rb
+++ b/spec/mixlib/log_spec.rb
@@ -130,6 +130,32 @@ describe Mixlib::Log do
     lambda { Logit.debug("Gimme some sugar!") }.should_not raise_error
   end
 
+  context "#warn_once" do
+    it "should warn the first time a given caller logs, but not subsequent times" do
+      expect(Logit).to receive(:warn).with("hi").exactly(1).times
+      expect(Logit).to receive(:debug).with("WARN: hi").exactly(2).times
+      1.upto(3) do
+        Logit.warn_once("hi")
+      end
+    end
+
+    it "should warn the first time a given caller logs, but not subsequent times, even if the message is different" do
+      expect(Logit).to receive(:warn).with("hi 1").exactly(1).times
+      expect(Logit).to receive(:debug).with("WARN: hi 2").exactly(1).times
+      expect(Logit).to receive(:debug).with("WARN: hi 3").exactly(1).times
+      1.upto(3) do |i|
+        Logit.warn_once("hi #{i}")
+      end
+    end
+
+    it "should warn each time for different callers" do
+      expect(Logit).to receive(:warn).with("hi").exactly(3).times
+      Logit.warn_once("hi")
+      Logit.warn_once("hi")
+      Logit.warn_once("hi")
+    end
+  end
+
   it "should pass add method calls directly to logger" do
     logdev = StringIO.new
     Logit.init(logdev)
@@ -141,14 +167,14 @@ describe Mixlib::Log do
 
   it "should default to STDOUT if init is called with no arguments" do
     logger_mock = Struct.new(:formatter, :level).new
-    Logger.stub!(:new).and_return(logger_mock)
+    Logger.stub(:new).and_return(logger_mock)
     Logger.should_receive(:new).with(STDOUT).and_return(logger_mock)
     Logit.init
   end
 
   it "should have by default a base log level of warn" do
     logger_mock = Struct.new(:formatter, :level).new
-    Logger.stub!(:new).and_return(logger_mock)
+    Logger.stub(:new).and_return(logger_mock)
     Logit.init
     Logit.level.should eql(:warn)
   end