Update the cron provider to not update the crontab if the current cron entry is already there.

Author: ctennis

chef/lib/chef/provider/cron.rb

@@ -64,7 +64,12 @@ def action_create
           status = popen4("crontab -l -u #{@new_resource.user}") do |pid, stdin, stdout, stderr|
             stdout.each_line do |line|
               if cron_found
-                crontab << "#{@new_resource.minute} #{@new_resource.hour} #{@new_resource.day} #{@new_resource.month} #{@new_resource.weekday} #{@new_resource.command}\n"
+                cronline = "#{@new_resource.minute} #{@new_resource.hour} #{@new_resource.day} #{@new_resource.month} #{@new_resource.weekday} #{@new_resource.command}\n"
+                if(line == cronline)
+                  Chef::Log.debug("Skipping existing cron entry '#{@new_resource.name}'")
+                  return
+                end
+                crontab << cronline
                 cron_found = false
                 next
               end
@@ -76,6 +81,7 @@ def action_create
             end
           end
 
+
           status = popen4("crontab -u #{@new_resource.user} -", :waitlast => true) do |pid, stdin, stdout, stderr|
             crontab.each { |line| stdin.puts "#{line}" }
             stdin.close

chef/spec/unit/provider/cron_spec.rb

@@ -128,7 +128,7 @@
     @provider.action_create
   end
 
-  it "should update the cron entry if it exists" do
+  it "should update the cron entry if it exists and has changed" do
     @status = mock("Status", :exitstatus => 0)
     @stdin = mock("STDIN", :null_object => true)
     @stdout = mock("STDOUT", :null_object => true)    
@@ -142,7 +142,36 @@
     @provider.stub!(:popen4).and_yield(@pid, @stdin, @stdout, @stderr).and_return(@status)
     Chef::Log.should_receive(:info).with("Updated cron '#{@new_resource.name}'")
     @provider.action_create
+  end
+
+  it "should not update the cron entry if it exists and has not changed" do
+    resource = mock("Chef::Resource::Cron",
+      :null_object => true,
+      :name => "foo",
+      :minute => "30",
+      :hour => "*",
+      :day => "*",
+      :month => "*",
+      :weekday => "*",
+      :command => "/bin/true"
+    )
+    provider = Chef::Provider::Cron.new(@node, resource)
 
+
+    @status = mock("Status", :exitstatus => 0)
+    @stdin = mock("STDIN", :null_object => true)
+    @stdout = mock("STDOUT", :null_object => true)    
+    @stderr = mock("STDERR", :null_object => true)
+    @pid = mock("PID", :null_object => true)
+    @stdout.stub!(:each_line).and_yield("# Chef Name: bar").
+      and_yield("* 10 * * * /bin/false").
+      and_yield("# Chef Name: foo\n").
+      and_yield("30 * * * * /bin/true\n")
+    provider.stub!(:popen4).and_yield(@pid, @stdin, @stdout, @stderr).and_return(@status)
+    Chef::Log.should_not_receive(:info).with("Updated cron '#{@new_resource.name}'")
+    Chef::Log.should_receive(:debug).with("Skipping existing cron entry '#{@new_resource.name}'")
+    provider.cron_exists = true
+    provider.action_create
   end
 end