Re: Generic flow string parser

[Thomas Monjalon <thomas@monjalon.net>]

This thread is an API suggestion, it should be discussed in
the developer mailing list (did the Cc here).

29/04/2023 16:23, Cliff Burdick:
> > Would rather the flow parser was rewritten as well. Doing open coded
> > parser is much more error prone and hard to extend versus writing the
> > parser in yacc/lex (ie bison/flex).
> 
> I agree, and that's kind of why the original suggestion of using testpmd
> came from. Writing a new parser is obviously the better choice and would
> have been great if testpmd started that way, but a significant amount of
> time was invested in that method. Since it works and is tested, it didn't
> seem like a bad request to build off that and bring that code into an rte_
> API. I'd imagine building a proper parser would not just require the parser
> piece, but also making sure all the tests now use that, and also the legacy
> testpmd was converted. It seemed unlikely all of this could be done in a
> reasonable amount of time and a lot of input from many people. Given the
> amount of debugging I (and others) have spent on figuring on why a flow
> spec didn't work properly, this could be a huge timesaver for new projects
> like Tom mentioned.
> 
> On Fri, Apr 28, 2023 at 5:04 PM Stephen Hemminger <
> stephen@networkplumber.org> wrote:
> 
> > On Fri, 28 Apr 2023 12:13:26 -0700
> > Cliff Burdick <shaklee3@gmail.com> wrote:
> >
> > > Hi Stephen, it would definitely not be worthwhile to repeat everything
> > > that's already tested with testpmd. I was thinking that given that there
> > > already is a "flow_parse" function that does almost everything needed,
> > > something like that could be exposed. If we think of the testpmd flow
> > > string as a sort of "IR" for string flow specification, that would allow
> > > others to implement higher-level transform of a schema like JSON or YAML
> > > into the testpmd language. Due to the complexity of testpmd and how it's
> > > the source of true for testing flows, I think it's too great of an ask to
> > > have testpmd support a new type of parsing. My only suggestion would be
> > > to take what already exists and expose it in a public API that is included
> > > in a DPDK install.

So the only things we need are 2 functions, if I understand well:

int rte_flow_to_text(const struct rte_flow*);
struct rte_flow *rte_flow_from_text(const char *);

Here I assume the output of rte_flow_from_text() would be a created flow,
meaning it calls rte_flow_create() under the hood.
Is it what you wish?
Or should it fill port ID, attributes, patterns and actions?