Supports health checking

[MichaelScofield]

As GreptimeTeam/greptimedb#4674 suggests, a method like is_connected is good to have in our Go SDK.

[killme2008]

We already have the heath checking protocol

https://github.com/GreptimeTeam/greptime-proto/blob/973f49cde88a582fb65755cc572ebcf6fb93ccf7/proto/greptime/v1/health.proto#L26

[daviderli614]

@killme2008 @MichaelScofield
In the greptime healthcheck proto, the message returned by HealthCheckResponse is empty. It can only determine whether the network is connected. It should return a judgment similar to ready or ok field?

I added a PR and here are the results:

• The GreptimeDB running:

go run main.go
2024/09/11 01:54:47 health check response:

• The GreptimeDB stop:

go run main.go 
2024/09/11 01:54:38 rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing: dial tcp 127.0.0.1:4001: connect: connection refused"
2024/09/11 01:54:38 health check response: <nil>

[MichaelScofield]

@daviderli614 It's expected that the response body is empty. When the response is successfully returned, it means the server's connectivity is good, and that's all we need (fow now).

[daviderli614]

@daviderli614 It's expected that the response body is empty. When the response is successfully returned, it means the server's connectivity is good, and that's all we need (fow now).

ok, PTAL: #45

[MichaelScofield]

@daviderli614 I've merged #45 , please release it and don't forget to update our docs.

[daviderli614]

A new version v0.5.2 was released to users:

go get -u github.com/GreptimeTeam/[email protected]

Use example: https://github.com/GreptimeTeam/greptimedb-ingester-go/tree/main/examples/healthcheck

#48
After this is merged, can write health check and hints docs together.