cmd: fix outputting resources for CVS mode if only one exists.

[fatih]

This PR fixes the --format csv output for commands that only output a single item. The gocsv package is not able to print individual structs and expects a slice of structs. We fix the issue by explicitly wrapping individual items with a slice.

There is a side effect, though. This changes how we print in JSON mode: instead of printing a single item, it's now printing a list with a single item in it.

Before

$ pscale database show planetscale --format csv
Error: cannot use database.Database, only slice or array supported

After:

$ pscale database show planetscale --format csv
Name,CreatedAt,UpdatedAt,Notes
planetscale,1614012928571,1617039724414,You're looking at it.

fixes: https://github.com/planetscale/project-big-bang/issues/224

[iheanyi]

Is there another way of doing this? Could we perhaps do this hack only at the CSV level?

[fatih]

Is there another way of doing this? Could we perhaps do this hack only at the CSV level?

I checked the gocsv package and it doesn't support any options to change it. We could use an if/else clause for each show function, but that introduces more code than anticipated:

Instead of:

return ch.Printer.PrintResource(toDatabases([]*ps.Database{database}))

We only wrap if it's CSV:

if ch.Printer.Format() == printer.CSV {
	return ch.Printer.PrintResource(toDatabases([]*ps.Database{database}))
} else {
	return ch.Printer.PrintResource(toDatabase(database))
}

[fatih]

There is another solution, but this solution requires quite a work. Before I choose gocsv, we were using encoding/csv from the stdlib. One problem with the package is, it's not able to Marshall a struct or a slice of structs. Instead one has to use a slice of [][]string records. This would mean that each struct had to implement a method or function that would return a slice of records. But adding it to every single resource wasn't easy and required quite a work. We started using gocsv to get rid of it.

But after writing it, I think we could use a mixture of both approaches. Let me check locally whether it's worth it.

[fatih]

@iheanyi check this out: a7251a0

[iheanyi]

LGTM! Thanks for doing this!