JSON input / output for CLI utilities

[Andrew Walker]

On Sat, May 29, 2021 at 5:55 AM Martin Schwenke <martin at meltin.net> wrote:

> Hi Andrew,
>
> On Thu, 27 May 2021 17:42:20 -0400, Andrew Walker via samba-technical
> <samba-technical at lists.samba.org> wrote:
>
> > I know we've added JSON output to a few of the CLI utils. Over the past
> > year or so I've added this to various utils in FreeNAS (using
> libjansson).
> > Is there an overall strategy for this? I'd be happy to upstream what I
> have.
>
> Sounds good!
>
> > Also is there an effort to add support for JSON input to them?
>
> Your effort appears to be it!  Thanks for that!  :-)
>
> One wishlist item to think about... and my example is for CTDB...  :-)
>
> If adding JSON output and, perhaps, input it would cool to have the
> command-line tools be able to run in a mode where they stay connected
> to the relevant Unix domain socket.  The most useful example would
> allow "ctdb statistics" to be repeatedly run within the one session, so
> a reporting tool can periodically collect the output without the need
> to reconnect.
>
> This could go hand-in-hand with addition of an interactive mode on
> tools that don't have one (e.g. "ctdb").
>
> If this is an interesting idea then I'm happy to try to work on that
> with you in whatever time I have available...
>
> peace & happiness,
> martin
>

Yeah, I have some added for most of the ctdb commands.

truenas# ctdb -j status | jq
{
  "nodemap": {
    "node_count": 2,
    "deleted_node_count": 1,
    "nodes": [
      {
        "pnn": 0,
        "address": "192.168.122.176",
        "flags_str": "OK",
        "flags_raw": 0,
        "partially_online": false,
        "this_node": true
      }
    ]
  },
  "generation": 1598490685,
  "size": 1,
  "vnnmap": [
    {
      "hash": 0,
      "lmaster": 0
    }
  ],
  "recovery_mode_raw": 0,
  "recovery_mode_str": "NORMAL"
}

This one will take a little more time since in the patchset I duplicated
many functions from /lib/audit_logging to separate library
"/lib/json_minimal" to have some minimal set of JSON-related functions to
make bolting-on JSON support somewhat simpler.