Subject: Re: [PATCH net-next 1/3] tools: ynl: cli: Add --list-attrs option to show operation attributes

From: Jakub Kicinski <[email-masked]>
Date: Mon, 17 Nov 2025 17:35:03 -0800

On Sun, 16 Nov 2025 21:28:43 +0200 Gal Pressman wrote:
> Add a --list-attrs option to the YNL CLI that displays information about
> netlink operations, including request and reply attributes.
> This eliminates the need to manually inspect YAML spec files to
> determine the JSON structure required for operations, or understand the
> structure of the reply.
> 
> Example usage:
>   # ./cli.py --family netdev --list-attrs dev-get
>   Operation: dev-get
> 
>   Do request attributes:
>     - ifindex: u32
>       netdev ifindex
> 
>   Do reply attributes:
>     - ifindex: u32
>       netdev ifindex
>     - xdp-features: u64 (enum: xdp-act)
>       Bitmask of enabled xdp-features.
>     - xdp-zc-max-segs: u32
>       max fragment count supported by ZC driver
>     - xdp-rx-metadata-features: u64 (enum: xdp-rx-metadata)
>       Bitmask of supported XDP receive metadata features. See Documentation/networking/xdp-rx-metadata.rst for more details.
>     - xsk-features: u64 (enum: xsk-flags)
>       Bitmask of enabled AF_XDP features.
> 
>   Dump reply attributes:
>     - ifindex: u32
>       netdev ifindex
>     - xdp-features: u64 (enum: xdp-act)
>       Bitmask of enabled xdp-features.
>     - xdp-zc-max-segs: u32
>       max fragment count supported by ZC driver
>     - xdp-rx-metadata-features: u64 (enum: xdp-rx-metadata)
>       Bitmask of supported XDP receive metadata features. See Documentation/networking/xdp-rx-metadata.rst for more details.
>     - xsk-features: u64 (enum: xsk-flags)
>       Bitmask of enabled AF_XDP features.

Could you try to detect that do and dump replies are identical 
and combine them? They are the same more often than not so 
I think it'd be nice to avoid printing the same info twice.

> Reviewed-by: Nimrod Oren <[email-masked]>
> Signed-off-by: Gal Pressman <[email-masked]>
> ---
>  tools/net/ynl/pyynl/cli.py | 55 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/tools/net/ynl/pyynl/cli.py b/tools/net/ynl/pyynl/cli.py
> index 8c192e900bd3..7ac3b4627f1b 100755
> --- a/tools/net/ynl/pyynl/cli.py
> +++ b/tools/net/ynl/pyynl/cli.py
> @@ -7,6 +7,7 @@ import os
>  import pathlib
>  import pprint
>  import sys
> +import textwrap
>  
>  sys.path.append(pathlib.Path(__file__).resolve().parent.as_posix())
>  from lib import YnlFamily, Netlink, NlError
> @@ -70,6 +71,8 @@ def main():
>      group.add_argument('--dump', dest='dump', metavar='DUMP-OPERATION', type=str)
>      group.add_argument('--list-ops', action='store_true')
>      group.add_argument('--list-msgs', action='store_true')
> +    group.add_argument('--list-attrs', dest='list_attrs', metavar='OPERATION', type=str,
> +                       help='List attributes for an operation')
>  
>      parser.add_argument('--duration', dest='duration', type=int,
>                          help='when subscribed, watch for DURATION seconds')
> @@ -128,6 +131,40 @@ def main():
>      if args.ntf:
>          ynl.ntf_subscribe(args.ntf)
>  
> +    def print_attr_list(attr_names, attr_set):

It nesting functions inside main() a common pattern for Python?
Having a function declared in the middle of another function,
does not seem optimal to me, but for some reason Claude loves
to do that.

> +        """Print a list of attributes with their types and documentation."""
> +        for attr_name in attr_names:
> +            if attr_name in attr_set.attrs:
> +                attr = attr_set.attrs[attr_name]
> +                attr_info = f'  - {attr_name}: {attr.type}'
> +                if 'enum' in attr.yaml:
> +                    attr_info += f" (enum: {attr.yaml['enum']})"
> +                if attr.yaml.get('doc'):
> +                    doc_text = textwrap.indent(attr.yaml['doc'], '    ')
> +                    attr_info += f"\n{doc_text}"
> +                print(attr_info)
> +            else:
> +                print(f'  - {attr_name}')
> +