Rename 'details' to 'components' in health actuator JSON

[philwebb]

Currently we have "details" in the JSON that represents both details of a Health and components of CompositeHealth. I would like to rename the latter to components.

The catch is we need to do this in a back compatible way.

[spencergibb]

This change broke a test in spring-cloud-netflix looking for 'details'. Doesn't seem to be backward compatible. https://github.com/spring-cloud/spring-cloud-netflix/blob/40ec6066c1e82a447314ebe0b45ca34e9e7034ce/spring-cloud-netflix-hystrix/src/test/java/org/springframework/cloud/netflix/hystrix/HystrixOnlyTests.java#L86-L93

Changing "details" to "components" fixes it. I can point you to the jenkins build if you'd like.

[wilkinsona]

As far as I can tell, there's no Accept header being sent in the test so it's saying that it'll happily accept anything. If you specify application/vnd.spring-boot.actuator.v2+json you should get a response with details in it rather than components.

[spencergibb]

Ok. I think of backward-compatible as the user shouldn't have to make a change. This is opt-in to backward-compatibility. There should be something in a migration guide then.

[wilkinsona]

I'm not sure I agree with that. Your client was saying that it was happy to accept anything, but was actually only capable of consuming application/vnd.spring-boot.actuator.v2+json. With an appropriate accept header that expressed the client's capabilities, no change would have been necessary.

That said, there may be plenty of users that have clients that do not send an Accept header and can also only consume application/vnd.spring-boot.actuator.v2+json. IMO, this fits within Boot's goal of minor updates causing at most minor pain on upgrade. Let's see what the rest of the team thinks.

[spencergibb]

there may be plenty of users that have clients that do not send an Accept header and can also only consume application/vnd.spring-boot.actuator.v2+json.

This was what I was thinking as well.