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

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 10 Mar 2017 16:22:49 +0000
"Wiles, Keith" <keith.wiles@intel.com> wrote:

> > On Mar 10, 2017, at 10:06 AM, Stephen Hemminger <stephen@networkplumber.org> wrote:
> > 
> > On Fri, 10 Mar 2017 15:25:31 +0000
> > "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.
> >>   
> > 
> > It would be great if all DPDK examples used a similar architecture. And having a common
> > infrastructure would help.
> > 
> > But not sure it needs to be special. Why should this be DPDK specific?
> > What you are building really ends up being an application
> > framework at some point. Surely, there are lots of others already in open source.
> > 
> > Heck even VPP has its own CLI inside.  
> 
> I have been looking for one for years and never found one that met my needs of easy to use and easy to understand. If you can find a better one then please let me know.
> 
> This code does use some DPDK APIs but they can be removed to make it standalone and the first version I did was standalone. Some of the ones I found were similar to cmdline and some took it a step farther by trying to do everything one would ever need in a CLI. Those are way too big and difficult to use, then you have the ones that are barely a step above readline or just writing you own. The cmdline interface falls closer to the trying to do everything for you, by converting strings into values with structures/macros difficult to understand at a glance. IMHO this one is simple and easy to understand.
> 
> But in truth the cmdline interface in DPDK is difficult to use and to write code for, takes way to many lines of code to make a simple command. The current Cmdline is  also not dynamic, which makes it difficult to add features on the fly.
> 
> All of the commands are at the same level and using a directory structure allows the developer to use what directory path he takes to denote a context for the command. As the example of converting test-pmd to use CLI the number of lines dropped from 12.6K to 4.5K lines. The cmdline code is also not consider to be production quality (from the docs) and I would like to fix that problem for DPDK.
> 

If you look beyond the simple C model there are a lot.
 TCL
 http://wanderinghorse.net/computing/shellish/eshell.html

Though these may not match what is needed.  Agree that the current cmdline() method is not suitable.