Support `/ping` endpoint

[mr-karan]

Clickhouse returns a HTTP 200 response for /ping URL. However, this library doesn't support proxying that.

I want to add that /metrics won't work always, because that is optional and moreover, user can set any value for metrics endpoint (as mentioned here: https://clickhouse.com/docs/en/operations/server-configuration-parameters/settings/#server_configuration_parameters-prometheus)

/ping should be the standard way to do healthchecks.

In health-check scripts use GET /ping request. This handler always returns “Ok.” (with a line feed at the end). Available from version 18.12.13.

https://clickhouse.com/docs/en/interfaces/http/

Additionally, queries on / are also proxied to /query which feels wrong too.

If you make a GET / request without parameters, it returns 200 response code and the string which defined in http_server_default_response default value “Ok.” (with a line feed at the end)

^ To conform to the API of Clickhouse, I believe the proxy should behave the same.

[vfoucault]

Hi @mr-karan,

It seems right to align chproxy on clickhouse api.

Feel free to issue a PR to fix this is you know how.

[gontarzpawel]

Hi @mr-karan , this feature has been released along with the version v0.17.0

[allen12921]

@gontarzpawel I still get unsupported path: "/ping" with the latest chproxy ver. 1.21.0 Is there any configs missed?

[ssube]

Is this supported in recent versions? I am also getting unsupported path: "/ping" errors on the server side, which looks like the code at https://github.com/ContentSquare/chproxy/blob/master/main.go#L252. I don't see a case for "/ping" there - what am I missing?