enhancement: support for consul TCP health checks

[Kosta-Github]

consul just recently added support for native TCP health checks (hashicorp/consul#1130). Can this be be supported by registrator as well?

With something like:

SERVICE_<PORT>_CHECK_TCP=true

[anklos]

Also looking for supoort for consul health checks.

just wonder what is the check here: https://github.com/gliderlabs/registrator/blob/master/consul/consul.go#L62?

[anklos]

actually you can put metadata in dockerfile to define SERVICE_CHECK_HTTP for the health check endpoint.

[ianmcorvidae]

I believe this issue should be closed, TCP checks are now supported.

[ralphQi]

"SERVICE__CHECK_TCP=true" dose not work

my solution is "SERVICE_CHECK_SCRIPT=nc -z ip port"