Is there a way to retrieve the CAS from the document?

[xavierchow]

As one of the approaches to concurrency-safe mutating document, I need to get the CAS from the document and replace the doc with it.

I didn't find a documentation about the CAS retrieving, digging into the code it seems the findById only gets back the value(that is replaced by content according to latest sdk)

node-ottoman/src/model/create-model.ts

Lines 190 to 192 in d8a4936

	const key = _keyGenerator!(keyGenerator, { metadata, id }, keyGeneratorDelimiter);
	const { value: pojo } = await collection().get(key, findOptions);

Will it be a good idea to have the ottoman to support both query CAS and update with it?
my two cents,

• Enhancement on FindByIdOptions to allow querying the CAS
• Enhancement on updateById to allow passing a CAS(probably via MutationFunctionOptions)?

[AV25242]

@gsi-alejandro can you please address this, I think we dont have this as a feature today like @xavierchow had mentioned. Is there a limitation as to not exposing the getOptions ?

[gsi-alejandro]

@AV25242

I think we can expose it, no problem.

[gsi-alejandro]

Next release we plan to expose a way to return the CAS value when available.

[xavierchow]

@gsi-alejandro hey, any updates about this?

[superbogy]

+1

[AV25242]

@gsi-alejandro where are we on this ? cc @ejscribner @thejcfactor

[bsdelf]

another solution is:

• let IDocument hold the CAS as its internal data
• add a boolean parameter to IDocument.save() method to enable CAS check when updating

therefore SDK user won't explicitly use the CAS at all.