Health support

[cescoffier]

No description provided.

[Emily-Jiang]

This is the integration with MP Health by providing implicit readiness check - ready to receive traffic; liveness Health procedure - to be killed if DOWN.

[Emily-Jiang]

This will be just a spec statement regarding the integration with MP Health.

[danielkec]

This will be just a spec statement regarding the integration with MP Health.

Initially this was proposed as integration with MP Health by providing implicit checks.
Such implicit check I would imagine having features like this:

• readiness is considered UP when onSubscribe signal has been registered on all the channels
• liveness is considered DOWN when onError, onComplete or cancel has been detected on any channel
• specified check name
• optional configuration for including/excluding channels

@Emily-Jiang Why leaving the idea?

[Emily-Jiang]

I don't have any objections to take it in. We need a PR to update spec and add tcks. Feel free to contribute @danielkec

[danielkec]

@Emily-Jiang PR #130 is ready

[Emily-Jiang]

Thank you @danielkec for proposing this PR. It serves a good talking point. I took a look at this PR and referred back to this issue. This issue needs a bit more description on describing what behaviour we want to define. What we are going to do with nack? Are we going to consider livessness to be DOWN when there is one channel has issues? At the moment, you introduce an opt out approach, should we use opt-in approaches? @cescoffier can you please comment on this?