Is there a way to suppress Firebase Functions Firestore triggers?

Question

I am using aggregation technique to keep track of aggregation data such as total number of doc, etc in Firestore.

Whenever an article document gets created or deleted, I am using Firebase functions' trigger to update aggregation data in a separate doc.

exports.onCreateArticle = functions.firestore.document("/articles/{articleId}").onCreate((change, context) => {
   // Increment a count & other aggregation data in a separate aggregation doc. This is done under transaction.
}

exports.onDeleteArticle= functions.firestore.document("/articles/{articleId}").onDelete((change, context) => {
   // Decrement a count & other aggregation data in a separate aggregation doc. This is done under transaction.
}

The thing is that I also want to have a weekly/monthly scheduled firebase function that moves set of articles into different collection (e.g. e.g. archiving process). For instance, this process deletes articles in /articles/{articleId} path and move them to /archivedArticles/{articleId} different path.

exports.scheduleArchive = functions.pubsub.schedule("every 7 days").onRun(async (context) => {
   /// move articles from `/articles/` to /archiveArticles/` and update aggregation doc at once.
}

The problem is that while this scheduled process updates the aggregation doc and deletes articles, there are many follow up onDelete triggers get called for each doc that got archived, and they unnecessarily attempt to update the aggregation doc which is already done by the scheduled process.

When the scheduled process kicks in, I do not want onDelete to be triggered due to following following reasons.

It is much more cost efficient to update aggregation doc at once (1 document write capacity vs 1 per each archived doc) when this scheduled job already know how many articles have been archived.
If I rely only on onDelete trigger for aggregation doc update, a large number of onDelete trigger will spin up, and transactional update from the trigger to aggregation doc will likely fail. It will also result in unnecessary firebase functions call.

Below are my questions.

Is there a way to suppress onDelete from getting called when my firebase functions deletes the documents? (vs users deleting the doc)
If I cannot suppress onDelete trigger, is there a way to distinguish if onDelete was triggered by user vs functions through firebase admin api? (e.g. using context & DocumentSnapshot parameters that get passed into each trigger event).

Doug Stevenson Doug Stevenson · Accepted Answer · 2019-12-13T01:18:47

No. Functions are always active when they're deployed. You would have delete it to stop it from working, or send it some other signal that you build yourself.
No, user information is not available in the trigger. The best you can do is have the user write their UID to the document to find out who it was, and make sure it's correct in security rules.

Is there a way to suppress Firebase Functions Firestore triggers?

1 Answers