Debugging Custom App Templates

#Utah , #App Engine Studio

Lauren McManamon

3 minute read

When creating applications on ServiceNow, instead of starting from scratch you have the option of utilizing app templates. These templates help save you time and effort, coming packed with predefined data, experiences, automation, and even security. Prior to the San Diego release, the only available templates were the ones that ServiceNow provided (see the full list here). However, San Diego opened the doors and allowed everyone access to create templates!

The November Tokyo store release further expanded this capability by finally providing developers with details on why a template can’t be published or created as-intended.

The Types of Broken App Templates

When building an app template, it is during the second “App review” stage that you will know which of the three buckets your potential app template falls into.

All Items Are Supported

If this were a video game with multiple endings, this would be considering the “best ending.” This means that all of the objects you developed will be available in the new custom template.

Some Items Aren’t Supported

While custom app templates support most features and metadata, there are some exceptions. Receiving this outcome means that you used some unsupported features, but they can be skipped over to complete the app template. The template creation process only skips items that should not impact the template or apps created from the template, and luckily it tells you exactly what will be skipped. Click here for a full list of what features are supported and which are skipped.

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NOTE: When looking at the “Your template won’t include the following items” list, be sure to try and scroll down on that bulleted list. No matter what font size you’re using, it will only show the first 4 issues. Any additional ones are hidden and currently there is no easy way to see that’s the case.

Your Updates Can’t Be Saved

Back to the video game metaphor, this would be the “bad ending.” While some unsupported things can be skipped, there are times when this is not the case. This means that the proposed template cannot be created until those errors are corrected. Similarly to those that are skipped, however, not only are they listed in a general fashion BUT also saved in detail to the Scan Failure table. To view that list in full, click View all errors in the paragraph after the screen title.

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Identifying App Template Errors

Clicking that View all errors link will take you to a filtered list of the Scan Failure table. The list will show the error type, what its effecting, and who created that functionality. From here, developers can work their way through what is wrong before trying again.

Error Message Definition Resolution
UNSUPPORTED_TABLE Record class for which there is no allow rule, and therebs an unknown level of support One or more unsupported records are unrecognized by App Engine Studio and must be removed for the template creation process to continue
DENIED_TABLE Record class for which there is a deny rule, and template creation isnbt supported The record class is explicitly denied and must be removed for the template creation process to continue
SCRIPTED_RECORD / SCRIPTED_APP Scripted rule that runs on each record in the app or a scripted rule that runs once for the app Current scripted deny rules include, but aren’t limited to custom metadata (the app has tables that extend the sys_metadata table), scoped administration (the app has scoped administration turned on), and template execution in progress (the template associated with the source app is currently being executed)

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