Re: [squid-users] logging of headers after request modification

On 05/08/2013 11:48 PM, Martin Sperl wrote:

> Actually I found one that works with the "least" amount of trickery...
>
> Logging via "%{Via}<h"
> And modifying the response headers the same way as the request headers.

Well, if you do not care which Via you are logging (request or
response), then <h will work. I thought you wanted to log the Via sent
to the server, not the Via sent to the client. The last/Squid portion of
that Via header will be the same, of course, but all the other entries
(if any) will usually differ. If you only care about the last/Squid
portion of Via, then logging response Via is a good solution.

> Still in my interpretation the "header modification" via
> request_header_access would fall into the "adaption and redirection"
> phase - maybe an idea for a change to trunk?

A correct implementation of that idea would require more work than it
may seem. From adaptation point of view, request_header_access vectoring
point is "post-cache REQMOD" while ICAP/eCAP and URL rewriter work at
"pre-cache REQMOD" point. We should not mix the two points.

We should add a new logformat code to log request headers sent by Squid,
but it is not trivial because those headers are currently not preserved
anywhere IIRC (and Squid may send multiple requests for a single client
request). Quality patches or sponsorships welcome.

For now, I polished [http::]>h and [http::]>ha logformat descriptions in
trunk to emphasize their pre-cache scope.

Cheers,

Alex.

> -----Original Message-----
> From: Alex Rousskov [mailto:rousskov_at_measurement-factory.com]
> Sent: Dienstag, 07. Mai 2013 18:22
> To: squid-users_at_squid-cache.org
> Subject: Re: [squid-users] logging of headers after request modification
>
> On 05/07/2013 09:49 AM, Martin Sperl wrote:
>
>> Is there any other configuration option (in squid 3.2) to log if an
>> ACL matches in the access-log? (which is all I essentially need)
>
> I have listed all the options I could think of, but I missed the
> "different logformat" options you mentioned. I think they boil down to:
>
> 4) Use multiple stdio/daemon loggers to append records to the same file.
> This does not require development (assuming current stdio/daemon code
> use O_APPEND when opening a log file). If you do not use NFS and manual
> page for open(2) implications are correct, then there should be no
> conflicts.
>
> 5) Use a single tcp logger address to log to the same file (requires
> not-yet-accepted trunk patch to work well). Here is a sketch for such a
> logger:
>
> nc -k -l 127.0.0.1 1234 > one-and-only.log
>
>
> HTH,
>
> Alex.
>
>
>> -----Original Message-----
>> From: Alex Rousskov [mailto:rousskov_at_measurement-factory.com]
>> Sent: Dienstag, 07. Mai 2013 17:37
>> To: squid-users_at_squid-cache.org
>> Subject: Re: [squid-users] logging of headers after request modification
>>
>> On 05/07/2013 08:03 AM, Martin Sperl wrote:
>>
>>> I have configured squid 3.2.7 logging with the following pattern to log:
>>>
>>> logformat xml ...<Via>%{Via}>ha</Via>...
>>> access_log daemon:/var/logs/squid/access_log.xml xml all
>>>
>>> But I have the problem, that the <VIA> fields stay "empty" (actually "-")...
>>>
>>> So I wonder why and how I can change that, so that I get the Via header as well...
>>
>>> P.s: I am modifying the VIA header in my config like this under some circumstances:
>>> request_header_access Via allow CUSTOM_ACL
>>> request_header_access Via deny all
>>> request_header_replace Via mypersonalvalue
>>
>>> The application sees the "expected" value in the Via header, so that
>>> itself is not an issue - only logging the header is NOT working as
>>> expected... (it actually only works IF
>>
>>
>> [http::]>ha logs request headers received by Squid and adapted by
>> ICAP/eCAP. It does not log request headers sent by Squid. There is
>> currently no logformat code to log the latter.
>>
>> If you want to log outgoing Via, your options include:
>>
>> 1) add a logformat code to log outgoing request headers (requires
>> development);
>>
>> 2) use "note" directive and %note logformat code to log mypersonalvalue
>> when needed (requires Squid trunk?)
>>
>> 3) move Via manipulation to ICAP/eCAP while disabling Squid's Via
>> generation (requires writing or adjusting an adaptation service).
>>
>
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Received on Thu May 09 2013 - 15:27:51 MDT