Handle Unicorn Deploy Once in a Production Environment

Question

So we've been successfully using Unicorn in a development only environment for the past few months. We have Content and Media Library items synced and always deployed which obviously shouldn't be the case when we go to a production environment, but I'm unsure of the best way to transition. Since we will have content in the Content and Media Library that we might need to "Deploy Once" and the rest we wouldn't want to ever deploy (we will work on deleting those items).

How can we configure this correctly. Is there a way to specify the serialization as deploy once in the serialization patch. Example, we have a patch that looks like this:

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <unicorn>
      <configurations>
        <configuration name="Feature.Navigation" description="Feature Navigation" dependencies="Foundation.Serialization" patch:after="configuration[@name='Foundation.Serialization']">
          <targetDataStore physicalRootPath="$(sourceFolder)\feature\navigation\Serialization" type="Rainbow.Storage.SerializationFileSystemDataStore, Rainbow" useDataCache="false" singleInstance="true" />
          <predicate type="Unicorn.Predicates.SerializationPresetPredicate, Unicorn" singleInstance="true">>
            <include name="Feature.Navigation.Templates" database="master" path="/sitecore/templates/Feature/Navigation" />
            <include name="Feature.Navigation.Renderings" database="master" path="/sitecore/layout/Renderings/Feature/Navigation" />
            <include name="Feature.Navigation.Media" database="master" path="/sitecore/media library/Feature/Navigation" />
            <include name="Feature.Navigation.Dictionary" database="master" path="/sitecore/content/global/dictionary/navigation" />
          </predicate>
        </configuration>
      </configurations>
    </unicorn>
  </sitecore>
</configuration>

So in that example above, the dictionary items and the media library are both areas in the content portion of Sitecore and ideally, we would only want to deploy once the items in those areas. Is there a way to configure Unicorn to deploy once for those folders.

Answer 1

Yep. Using the NewItemsOnly evaluator.

Add this under your <configuration> element.

<evaluator type="Unicorn.Evaluators.NewItemOnlyEvaluator, Unicorn" singleInstance="true"/>

You can find an example of this in your Unicorn folder. Unicorn.Configs.NewItemsOnly.example

---

Be aware.

Be aware of a few caveats though. I've been using this one myself in a scenario not too different from what you describe. And for most content, we had various example images and content set up - like menu elements for the Footer and so on.

What happened was, that the client wanted to get rid of some of these example navigational elements and therefore deleted them. Then complained they kept coming back on each deploy. Which is obvious when you think about it - just keep this in mind when layout out your configurations :-)