Optimistic Concurrency Control on Writes about bloodhound

[bitemyapp]

Your design for Version sounds good to me.

I agree IndexDocumentSettings rather than a separate function is probably the way to go.

For handling conflicts, we're talking about either a proper error or exception. Documentation on how to catch it is probably sufficient. Is it worth trying to parse out the new version number or is it mostly not going to matter and they just need to know it failed and to see the error body?

[MichaelXavier]

So I decided to actually try this out while writing tests for my change and I'm pretty sure ES is just putting some Java exception through a serializer. It would be awesome if we could parse out the exact version and stuff, but it looks like doing so would require us to parse an Error message which makes my skin crawl. For reference, here's the reply:

Response {responseStatus = Status {statusCode = 409, statusMessage = "Conflict"}, responseVersion = HTTP/1.1, responseHeaders = [("Content-Type","application/json; charset=UTF-8"),("Content-Length","144")], responseBody = "{\"error\":\"VersionConflictEngineException[[bloodhound-tests-twitter-1][2] [tweet][1]: version conflict, current [1], provided [1]]\",\"status\":409}", responseCookieJar = CJ {expose = []}, responseClose' = ResponseClose}

What would be a nice compromise though is I could look through the API conventions documentation and provide to start with:

isVersionConflict :: Reply -> Bool
isVersionConflict = (== 409) . statusCode . responseStatus

With more to come later.

[MichaelXavier]

Pushed a commit that implements this. Added a simple test case that writes a value with a version control strategy that requires the value to increment, fails to increment it and asserts that the index is rejected with a version conflict. Have a look and let me know what you think.

[bitemyapp]

@MichaelXavier other than my comment about the query appending, your commit looks good to me. Good tests, thank you! 👍

[bitemyapp]

I believe this is resolved and generally available now. Thank you @MichaelXavier ! 🐻 👍