Fix vtctlclient help

[deepthi]

Right now vtctlclient --help will list a bunch of flags.
Snippet:

$ vtctlclient --help
Usage of vtctlclient:
  -action_timeout duration
    	timeout for the total command (default 1h0m0s)
  -alsologtostderr
    	log to standard error as well as files

What we would like it to do is to return the list of valid commands after the list of flags similar to how vtctl --help works.

The commands are listed below, sorted by group. Use 'vtctl <command> -h' for more help.

Tablets:
  InitTablet DEPRECATED [-allow_update] [-allow_different_shard] [-allow_master_override] [-parent] [-db_name_override=<db name>] [-hostname=<hostname>] [-mysql_port=<port>] [-port=<port>] [-grpc_port=<port>] [-tags=tag1:value1,tag2:value2] -keyspace=<keyspace> -shard=<shard> <tablet alias> <tablet type>
  GetTablet <tablet alias>

While we are at it, we should also:

• Send output to stdout instead of stderr
• Remove any flags that are not actually used by vtctlclient

[deepthi]

Since we are planning to deprecate vtctlclient once #7058 is available, we could make sure to capture this in vtctldclient instead.
cc @ajm188

[ajm188]

Yeah, because the new client uses cobra we actually get this for free, e.g.

❯ ./bin/vtctldclient --help
Usage:
   [command]

Available Commands:
  GetKeyspace  
  GetKeyspaces 
  help         Help about any command

Flags:
      --action_timeout duration                timeout for the total command (default 1h0m0s)
      --alsologtostderr                        log to standard error as well as files
      --datadog-agent-host string              host to send spans to. if empty, no tracing will be done
      --datadog-agent-port string              port to send spans to. if empty, no tracing will be done
      ... [more flags]

I'll have to think about how to best filter out the default servenv flags from the help, but we're already halfway there 😄

[deepthi]

Since vtctlclient will be deprecated once vtctldclient reaches parity, this issue is no longer needed.

[ajm188]

(fwiw i also think this was resolved by the flag work)

[Anders-PlanetScale]

For future posterity. while vtctlclient --help does not display the list of commands available it looks like in v15 at least vtctlclient --server=X help does work. Example below with truncated output.

vtctlclient --server=localhost:15999 help
Available commands: 
Tablets:
  (DEPRECATED) InitTablet [--allow_update] [--allow_different_shard] [--allow_master_override] [--parent] [--db_name_override=<db name>] [--hostname=<hostname>] [--mysql_port=<port>] [--port=<port>] [--grpc_port=<port>] [--tags=tag1:value1,tag2:value2] --keyspace=<keyspace> --shard=<shard> <tablet alias> <tablet type>
  GetTablet <tablet alias>
  (DEPRECATED) UpdateTabletAddrs [--hostname <hostname>] [--ip-addr <ip addr>] [--mysql-port <mysql port>] [--vt-port <vt port>] [--grpc-port <grpc port>] <tablet alias> 
  DeleteTablet [--allow_primary] <tablet alias> ...
  SetReadOnly <tablet alias>

...

[deepthi]

(fwiw i also think this was resolved by the flag work)

not really. --help still prints only flags, except it now has the same behavior for vtctl as well as vtctlclient 😭

[deepthi]

Nice find @Anders-PlanetScale!
Inspired by that, I found out this works as well

$ vtctl --topo_implementation etcd2 --topo_global_root /vitess/global --topo_global_server_address localhost:2379 help