Re: [dpdk-dev] [RFC] New CLI for DPDK

[Olivier Matz <olivier.matz@6wind.com>]

Hi Keith,

On Thu, 23 Mar 2017 16:13:21 +0000, "Wiles, Keith" <keith.wiles@intel.com> wrote:
> > On Mar 10, 2017, at 9:25 AM, Wiles, Keith <keith.wiles@intel.com> wrote:
> > 
> > I would like to request for comments on a new CLI design and get any feedback. I have attached the cli.rst text, which is still a work in progress for you review.
> > 
> > I have also ported the CLI to a version of Pktgen on the ‘dev’ branch of the repo in DPDK.org.
> > 
> > http://dpdk.org/browse/apps/pktgen-dpdk/refs/?h=dev
> > 
> > I would like to submit the CLI library to be used in DPDK, if that seems reasonable to everyone. I need more testing of the API and Pktgen, but I feel it has a simpler design, easier to understand and hopefully make it easier for developers to add commands.
> > 
> > As an example I quickly converted over testpmd from CMDLINE to CLI (I just add a -I option to select CLI instead) and reduced the test-pmd/cmdline.c file from 12.6K lines to about 4.5K lines. I did not fully test the code, but the ones I did test seem to work.
> > 
> > I do not expect DPDK to convert to the new CLI only if it makes sense and I am not suggesting to replace CMDLINE library.
> > 
> > If you play with the new CLI in pktgen and see any problems or want to suggest new features or changes please let me know.
> > 
> > Comments on the cli.rst text is also welcome, but the cli.rst is not complete. I think this file needs to be broken into two one to explain the example and another to explain CLI internals.  
> 
> Any more comments on the CLI code for DPDK.
> 
> Should I submit a patch for DPDK or would it be better to push this into its own repo on DPDK?
> 

I agree that there is a large possibility of improvements in librte_cmdline.

Just for reference, I think this design was not that bad at the time it
was introduced:
- declaring commands as static variables makes sense when running on
  baremetal without malloc library
- implementing a readline-like part was also needed because not available
  on baremetal
- masking structures to the user was harder due to the lack of malloc
- having a cli is really helpful for a program like testpmd (both for
  a user or for an automatic test program)

Few efforts were made to enhance this library because it's not the heart
of dpdk.

The current status is acceptable to me: this library is mostly used
internally in dpdk for test apps, and application developers are free
to use a better one if they want.

But adding another cli lib in dpdk does not make sense to me. I think
the proper direction would be to remove the cli from dpdk and use a
good cli library that is available in distros. But for that:
- we need to find one
- we need to update all examples/tests that use the cmdline, and
  that will be a lot of work
- we need to enhance dpdk framework to better manage deps with
  external libraries

So, in my opinion, the CLI you are proposing should be hosted on another
repo.

Regards,
Olivier