Render health checks as JSON for ratpack-codahale-metrics

[wmacgyver]

per #416

I kept it simple and just use the Jackson mapper

[ldaley]

@rhart do you mind shepharding this one as you're our metrics expert?

[rhart]

No prob, will take a look tomorrow

[wmacgyver]

since I'm being shepherded, Baaaaaa....

[rhart]

Never say "Baaaa" to a Welshman ;)

[rhart]

@wmacgyver now we're returning json we should prob be using Context#byContent in the renderer, what do you think? There's an example in DefaultJsonRenderer https://github.com/ratpack/ratpack/blob/master/ratpack-jackson/src/main/java/ratpack/jackson/internal/DefaultJsonRenderer.java#L42

Also, I think we should use Context#getResponse()#send instead of Context#render to avoid another renderer lookup.

[wmacgyver]

sure, I'll make the changes you suggested tomorrow.

[coveralls]

Coverage decreased (-0.15%) when pulling 8d9b9c5 on wmacgyver:master into d9242af on ratpack:master.

[coveralls]

Coverage decreased (-0.11%) when pulling 8d9b9c5 on wmacgyver:master into d9242af on ratpack:master.

[rhart]

I'll merge this when I get back from hols. It'll be after 0.9.10

I'm thinking it might be worthwhile explicitly setting "no cache" response headers too. As I understand it you can't guarantee the browser won't cache the response without setting them. Unless you're explicit you're at the mercy of the browser.

[wmacgyver]

added http header to disable caching. I did all 3 variant to make sure it cover all the browsers. Hope that wasn't too over zealous.

[coveralls]

Coverage decreased (-0.52%) when pulling 6237d0b on wmacgyver:master into d9242af on ratpack:master.

[rhart]

Sorry it's taken so long but y'know, hols take priority :)

[wmacgyver]

@rhart no worries, thanks for the hand holding