RUBY-306 added missing file

lib/mongo/util/logging.rb

@@ -0,0 +1,42 @@
+module Mongo
+  module Logging
+
+    # Log a message with the given level.
+    def log(level, message)
+      return unless @logger
+      case level
+        when :debug then
+          @logger.debug "MONGODB [DEBUG] #{msg}"
+        when :warn then
+          @logger.warn "MONGODB [WARNING] #{msg}"
+        when :error then
+          @logger.error "MONGODB [ERROR] #{msg}"
+        when :fatal then
+          @logger.fatal "MONGODB [FATAL] #{msg}"
+        else
+          @logger.info "MONGODB [INFO] #{msg}"
+      end
+    end
+
+    # Execute the block and log the operation described by name and payload.
+    def instrument(name, payload = {}, &blk)
+      res = yield
+      log_operation(name, payload)
+      res
+    end
+
+    protected
+
+    def log_operation(name, payload)
+      @logger ||= nil
+      return unless @logger
+      msg = "#{payload[:database]}['#{payload[:collection]}'].#{name}("
+      msg += payload.values_at(:selector, :document, :documents, :fields ).compact.map(&:inspect).join(', ') + ")"
+      msg += ".skip(#{payload[:skip]})"  if payload[:skip]
+      msg += ".limit(#{payload[:limit]})"  if payload[:limit]
+      msg += ".sort(#{payload[:order]})"  if payload[:order]
+      @logger.debug "MONGODB #{msg}"
+    end
+
+  end
+end