Adding Global Flag in Modern CLI

[JyotikaGargg]

In order to migrate all the commands from Kong to Modern CLI,
I have started with one flag here : InputFile.

[shueybubbles]

inputType string

why is this a root level parameter?

[stuartpa]

This is a good question. Where should we put all these back-compat switches. They are needed either when the customer uses the query subcommand, or when the use uses no subcommand (which is defined in this Root type!).

Should we add all these back-compat switches to the Query subcommand, and then have them accessable to the Root when no subcommand is provided.

[shueybubbles]

this implies 3 different concepts -

1. input type
2. input file name
3. Output type

[stuartpa]

I think this is a copy and paste error (from outputType above)

[shueybubbles]

The sqlcmd package defines the main parameter structure for the query command, here https://github.com/microsoft/go-sqlcmd/blob/main/pkg/sqlcmd/connect.go

What I think you would do is update query.go here https://github.com/microsoft/go-sqlcmd/blob/main/cmd/modern/root/query.go to define the new modern command structure. That command implementation will construct a Connect object to pass to the Sqlcmd instance to do its work.
modern/root/query.go will eventually replace cmd/sqlcmd/sqlcmd.go

[stuartpa]

I've added discussion #193 to work through how we do this, we can use this PR as a proof point.

Part of the issue here is we need to make, in this case, the -i switch available on the root command (for back-compat), and on the query subcommand. What's the best way to wire this up. Add the -i flag to query.go, and somehow provide a mechanism to also have it made available on the root command (when no sub-command is presented).

We also need to deal with when to show help. Presuming we make it so the -i command works when no sub-command is added, should we show help for -i when sqlcmd --help is run?