[Dnsmasq-discuss] [PATCH] --bind-dynamic and fast netlink changes

[Simon Kelley]

Cool. I just pushed two commits. One to implement --log-debug and one to
enable it for those messages.

Simon.


On 09/03/2021 00:01, Petr Menšík wrote:
> Hi,
> 
> --debug-log is good as well, whatever suits you more.
> 
> On 3/2/21 6:49 PM, Simon Kelley wrote:
>> On 01/03/2021 10:56, Petr Menšík wrote:
>>> On 3/1/21 1:02 AM, Simon Kelley wrote:
>>>> That looks sensible except for one thing. I wasn't sure about the
>>>> logging in the first place, and having to add Yet Another Config Option
>>>> to control it is the last straw; I think it's better just removed.
>>> Is there any good way to monitor them without logging possible? I
>>> considered also enabling the log just in debug mode (-d). It seems
>>> better if it can be configured separately. Still, I find those logs very
>>> important to observe listener changes. It was hard to watch more than
>>> single change using debugger.
>>>
>>> I also considered using log-queries option, because it logs quite often
>>> anyway. But I think it would be better to have separate option.
>>
>> For debugging, logging is useful for fixing these problmes, but once
>> this is working, is this logging providing anything useful for someone
>> who is setting up and configuring a dnsmasq installation?  I think that
>> was my hesitation to this originally. I'd expect bind-dynamic to just
>> work, in the same was that the other two bind- modes do, and not to need
>> to fill the logs with details of its internal behaviour.
>>
>> Debug mode is not a good choice, since you may well want to control
>> logging independently of making forking and suchlike work in a way which
>> makes running under gdb.
>>
>> Maybe to should have a new option to control debug-level logging.
>> Without that set my_syslog could just discard any calls with LOG_LEVEL
>> set to DEBUG (which is just the ones we're talking about, as far as I
>> can see, but could be extended later, once the facility exists.) I'm
>> sure the various varieties of syslog daemons can be configured to dom
>> something similar, but there's still the overhead of talking to them.
>>
>>
>>
>>>
>>> Logging those events seems right to me. But they should not be logged
>>> during netlink reading, but after it. It seems quite complicated to
>>> gather changed listeners after iface_enumerate is finished however. They
>>> are usually just one or two lines, just during my artificial test, it
>>> was worth noting. I should mention, the first commit itself fixed it
>>> well on 2.79 in RHEL8. Listeners logging still in place and slowing down
>>> the test. Yet it always passed.
>>>
>>> I removed them just as precaution to improve performance. As a last
>>> resort, could they remain there under compile time define?
>>>
>>
>> Yes, but I like my --debug-log option better. What do you think?
>>
>>
>> Simon.
>>
>>>>
>>>>
>>>> Will apply the others and test tomorrow.
>>> Great, if you need help with testing, just let me know.
>>
>> Sorry, yesterday didn't go to plan. Applying patches now.
>>
>>
>> Simon.
>>
>>>
>>> Cheers,
>>> Petr
>>>
>>
>