Re: Associating accesses with cache.log entries

I like the idea too.

2008/11/27 Kinkie <gkinkie_at_gmail.com>:
> On Thu, Nov 27, 2008 at 4:21 AM, Mark Nottingham <mnot_at_yahoo-inc.com> wrote:
>> I've been playing around with associating specific requests with the debug
>> output they generate, with a simple patch to _db_print along these lines:
>>
>> if (Config.Log.accesslogs && Config.Log.accesslogs->logfile) {
>> seqnum = LOGFILE_SEQNO(Config.Log.accesslogs->logfile);
>> }
>> snprintf(f, BUFSIZ, "%s %i| %s",
>> debugLogTime(squid_curtime),
>> seqnum,
>> format);
>>
>> This leverages the sequence number that's available in custom access logs
>> (%sn).
>>
>> It's really useful for debugging requests that are causing problems, etc;
>> rather than having to correlate times and URLs, you can just correlate
>> sequence numbers. It also makes it possible to automate debug output (which
>> is the direction I want to take this in).
>
> Looks interesting to me.
>
>> beyond the obvious cleanup that needs to happen (e.g., outputting '-' or
>> blank instead of 0 if there isn't an access log line associated, a few
>> questions;
>>
>> * How do people feel about putting this in cache.log all the time? I don't
>> think it'll break any scripts (there aren't many, and those that are tend to
>> grep for specific phrases, rather than do an actual parse, AFAICT). Is the
>> placement above appropriate?
>
> I'd avoid the | character, but apart from that it makes sense to me
>
>> * The sequence number mechanism doesn't guarantee uniqueness in the log
>> file; if squid is started between rotates, it will reset the counters. Has
>> fixing this been discussed?
>
> I don't think that uniqueness has much value, correlating seqnum with
> the timestamp will address any uncertain cases.
>
>> * Is it reasonable to hardcode this to associate the numbers with the first
>> configured access_log?
>>
>> * To make this really useful, it would be necessary to be able to trigger
>> debug_options (or just all debugging) based upon an ACL match. However, this
>> looks like it would require changing how debug is #defined. Any comments on
>> this?
>
> YES! It's something I've been thinking about for some time.
> Count me in.
>
> --
> /kinkie
>
>
Received on Thu Nov 27 2008 - 06:59:00 MST