Re: Maybe too strict check for frontend/backend name conflicts

On Fri, 2 Nov 2007, Willy Tarreau wrote:

> On Fri, Nov 02, 2007 at 11:43:23AM +0100, Krzysztof Oledzki wrote:
>>> Take a look at how I managed to pass the error messages in return from
>>> dumpstats.c,
>> OK, found it.
>>
>>> or even in backend.c (backend_parse_balance, in latest master-git).
>> There is no backend_parse_balance. :( Checked both
>> 0e21b201e6892c25e8264e43ceb12fed6d0c5e82 (1.3.13) and
>> 85130941e7ba66656e302a68a211c3834d7d5a93 (master).
>
> Grrr. I was 100% sure I had pushed to the web tree, and obviously I was
> wrong, only 1.3.13 was updated. It's now updated master too.

OK, get it.

>>> I've not found the perfect interface to all parsing functions yet, but
>>> I'm sure we'll soon have something standard for use with all
>>> sub-components.
>>>
>>> It will also greatly improve error messages report since each level can
>>> complete the message with more information, and the last level can put
>>> the line number which we don't always have. I'll have to update ACLs to
>>> use the same interface so that we can at last get human-readable error
>>> messages for incorrectly written ACLs.
>>
>> How about adding a global "char errstr[BUFSIZE]"? Each function can then
>> easily return a appropriate error message. No need to pass additional
>> buffers and lengths.
>
> That's what I thought about first, then I realized that it would not be
> convenient for intermediate functions to prefix the error messages with
> their part of context. For instance, such a message could be completed
> by 4 different levels :
>
> "Proxy xxx: rule yyy: acl zzz requires HTTP mode"
> <--- level 4 ---->
> <------- level 3 -------->
> <------------ level 2 ------------->
> <------------------ level 1 ------------------>
>
> So in certain circumstances, the error message will be on the caller's
> stack.

Oh, indeed. But this still can be solved without passing additional references. Attached example code that produces:

"Proxy xxx: rule yyy: acl zzz requires HTTP mode"

However, for long messages I think multi-line output may be better:   Refusing to use duplicated proxy 'aqq1' with conflicting capabilities: backend/backend!   Proxy 'www.example.com': unable to find required default_backend: 'aqq1'.

Best regards,

                                 Krzysztof Olêdzki