Add a document:createOrUpdate route

[scottinet]

Document

Now this one is a bit counterintuitive. Until now, there weren't use cases for an upsert API route. Because document updates apply partial content modification to documents, it's normally not something we want to create a new document on the fly with only partial content.

However, here is a use case coming from one of our clients, which to me seems to justify the addition of that new route to Kuzzle:

Well, we have a use case where we want to maintain a list of recommendations for a user. Those reccomendations come from different sources from a kafka topic.

So when a recommendation is received we want to add it to the document for that user in our recommendations collection. If the customer is new, the document which matches the customer id will not exist yet. So we want to update the document by changing a specific set of recommendations OR create a new document with that user id and add the recommendation type. We don;t really want a collection per rec type, because that means millions of documents in each of those collections.

In that specific case, it is desirable to add partial content to a document, or to create a new one on the fly if needed.

[robkane1]

Thanks for adding this feature request. Just to add to this...

Without this feature, options are:

A: Call exists, wait for a response, then based on the response, call either create or update.

• too noisy
• creates a lot of synchronous traffic when we will potentially have spikes of >1m messages in an hour
• risk of triggering unnecessary rebalancing.

B: Aggregate our messages into a ktable and fire the compiled result of that into the kuzzle collection.

• makes recovery from a kuzzle failure easier
• creates an unnecessary storage and memory overhead
• message schema does't really suit a RDB - more suited to nosql
• overhead of creating external custom state store that operate across the consumer group
• replicating what we already have in kuzzle.

Given that kuzzle supports dynamic fields on documents and elasticsearch provides upsert functionality, seems reasonable to have this available in kuzzle.

Equivalent ES:

POST test/_update/1
{
  "doc": {
    "name": "new_name"
  },
  "doc_as_upsert": true
}