Add "took" attribute to SearchHits/ReactiveSearchHits

[ELHARROUGUI]

I am working on a Spring API that integrates with Elasticsearch, and my current task involves migrating from the Elasticsearch Java API Client to Spring Data Elasticsearch. While doing so, I noticed that the response body in the Elasticsearch Java API Client includes a valuable attribute called "took", which shows the time (in milliseconds) it took to complete the request. However, this attribute is not accessible in the SearchHits (or ReactiveSearchHits) body in Spring Data Elasticsearch.

This feature is important for performance monitoring and debugging, as it allows developers to measure the responsiveness of Elasticsearch queries.

I propose adding support for retrieving the "took" attribute from SearchHits objects in Spring Data Elasticsearch, ensuring feature parity with the Elasticsearch Java API Client. This enhancement would improve the developer experience by providing essential timing information for queries.

I would be happy to contribute to this feature by submitting a PR if accepted. Thank you!

[sothawo]

Fell free to add it; just a thought: I think we should use a better name than took, perhaps something like executionDuration and instead of using an int or long use a java.time.Duration

[ELHARROUGUI]

Thank you, @sothawo ! I can't think of a better name than executionDuration either :)

I just wanted to point out that in the Elasticsearch Java API, the attribute is declared as tookInMillis (as a private long), but they use getTook() as the getter. The getter returns a TimeValue object (org.elasticsearch.core.TimeValue), which encapsulates the duration.

Following a similar approach, we could retrieve the long value from the TimeValue object like this:
long executionDurationInMillis = searchDocumentResponse.getTook().millis();
Then, we could return a java.time.Duration object instead of a long:
Duration executionDuration = Duration.ofMillis(executionDurationInMillis);

P.S.: java.time.Duration is not currently used in the org.elasticsearch.core.TimeValue class.

Does this approach sound good to you?

[sothawo]

yes, we need this mapping to a java.time.Duration as we cannot pass Elasticsearch classes through our API. So this change must be added in the org.springframework.data.elasticsearch.client.elc.SearchDocumentResponseBuilder class