CA-413424: Enhance xe help output

[BengangY]

The previous xe help is as below:

Usage: xe <cmd> [-s server] [-p port] ([-u username] [-pw password] or [-pwf <password file>]) [--traceparent traceparent] <other arguments>

A full list of commands can be obtained by running
	xe help -s <server> -p <port>

The previous xe help output lacked debug-related options and did not provide detailed parameter description.
The new xe help output is as follows:

Usage:
  xe <command>
    [ -s <server> ]            XenServer host
    [ -p <port> ]              XenServer port number
    [ -u <username> -pw <password> | -pwf <password file> ]
                               User authentication (password or file)
    [ --nossl ]                Disable SSL/TLS
    [ --debug ]                Enable debug output
    [ --debug-on-fail ]        Enable debug output only on failure
    [ --traceparent <value> ]  Distributed tracing context
    [ <other arguments> ... ]  Command-specific options

A full list of commands can be obtained by running
  xe help -s <server> -p <port>

[lindig]

When I run xe help I am getting this, which seems more comprehensive - see below. However, I like the proposed presentation of options in a table.

Usage: xe <command> [-s server] [-pw passwd] [-p port] [-u user] [-pwf password-file]
  [command specific arguments]

To get help on a specific command: xe help <command>
To get a full listing of commands: xe help --all

Common command list
-------------------
    cd-list, diagnostic-vm-status, network-list, snapshot-clone
    snapshot-copy, snapshot-disk-list, snapshot-export-to-template
    snapshot-reset-powerstate, snapshot-revert, snapshot-uninstall, sr-list
    template-export, template-uninstall, vm-cd-add, vm-cd-eject
    vm-cd-insert, vm-cd-list, vm-cd-remove, vm-checkpoint, vm-clone
    vm-compute-maximum-memory, vm-copy, vm-disk-add, vm-disk-list
    vm-disk-remove, vm-export, vm-import, vm-install, vm-list, vm-migrate
    vm-pause, vm-reboot, vm-reset-powerstate, vm-restart-device-models
    vm-resume, vm-shutdown, vm-snapshot, vm-snapshot-with-quiesce, vm-start
    vm-suspend, vm-uninstall, vm-unpause, vm-vif-list

[lindig]

Another way to format this in source code would be using {| ... |}

[psafont]

This is definitely better, but we really need to stop hard-coding this and autogenerate it, the OCaml libraries for generating CLIs take care of this

[changlei-li]

will you also change xe help? Different with xe or xe -h, it seems be on server side.

[BengangY]

Yes, I will.

[changlei-li]

I think for xe help you can manipulate the usage at client side and manipulate the remaining (Common command list .etc) at server side. Then the usage will keep consistent no matter if autogenerate it.

[BengangY]

When I run xe help I am getting this, which seems more comprehensive - see below. However, I like the proposed presentation of options in a table.
Yes, I just found xe and xe help are coming from different code. Will change all of them.

[BengangY]

This is definitely better, but we really need to stop hard-coding this and autogenerate it, the OCaml libraries for generating CLIs take care of this

Let me investigate how to auto-generate it.

[psafont]

Let me investigate how to auto-generate it.

We usually use cmdliner for these. But don't feel pressured into adding it for this PR. xe's CLI has many shortcomings and needs a good rework.

[lindig]

I think we should merge this. Moving towards Cmdliner will be a bigger change.