Rainer,
On 5/16/22 13:48, Christopher Schultz wrote:
Rainer,
I've been looking into this a little more in my production environment.
These errors are not super common, but there seems to be a steady
trickle of errors from my two services that have human users. I see 0
errors for my API-based services, which makes me think that I don't have
any performance issues... I probably have human users disappearing for
random reasons.
The errors in mod_jk.log look like this:
[Sun May 15 04:19:15.643 2022] [5859:139625025315392] [info]
ajp_process_callback::jk_ajp_common.c (2077): (myworker) Writing to
client aborted or client network problems
[Sun May 15 04:19:15.644 2022] [5859:139625025315392] [info]
ajp_service::jk_ajp_common.c (2773): (myworker) sending request to
tomcat failed (unrecoverable), because of client write error (attempt=1)
[Sun May 15 04:19:15.646 2022] [5859:139625025315392] [info]
service::jk_lb_worker.c (1595): service failed, worker myworker is in
local error state
[Sun May 15 04:19:15.646 2022] [5859:139625025315392] [info]
service::jk_lb_worker.c (1614): unrecoverable error 200, request failed.
Client failed in the middle of request, we can't recover to another
instance.
[Sun May 15 04:19:15.646 2022] [5859:139625025315392] [info]
jk_handler::mod_jk.c (2984): Aborting connection for worker=myworker
(Note that the last message "Aborting connection for worker=myworker"
may have a bug; my actual worker name has a name containing a hyphen (-)
and only the text before the hyphen is being emitted in that error
message.)
Anyway, when researching these errors, it would be helpful to me to know
which requests are failing. By looking at the access_log, I only see a
single request logged for 04:19:15 on that server so it's probably the
right one, but httpd says that the response code is 302 instead of e.g.
50x for an error.
When we log these kinds of errors, it would be great to know a few
things IMO:
1. What was the URL of the request
2. How long did the client wait for the response before we found we
couldn't write to the stream (or, conversely, the start-timestamp of the
request as well as the timestamp of the error, which I think is already
in the log itself)
I see the place in the code where the error is generated, but I'm not
familiar enough with the code to know how to add that kind of thing. The
function in question (ajp_process_callback) has a pointer to a
jk_ws_service_t structure. Is it as simple as also logging like this?
/* convert start-time to a string */
char[32] timestamp;
apr_strftime(timestamp, NULL, 32, "%Y-%m-%d %H:%M:%S",
r->r->request_time);
/* emit a detailed log message */
jk_log(l, JK_LOG_INFO,
"(%s) Request to (%s %s) started at %s,%ld",
ae->worker->name, r->method, r->req_uri, timestamp,
r->r->request_time.tm_usec);
Does anyone think this might be generally useful?
It looks like I needed a few more things in order to get this to work:
{
char *timestamp = malloc(32);
apr_time_exp_t *timerec = malloc(sizeof(apr_time_exp_t));
apache_private_data_t *ap = (apache_private_data_t*)r->ws_private;
apr_time_exp_gmt(timerec, ap->r->request_time);
apr_strftime(timestamp, NULL, 32, "%Y-%m-%d %H:%M:%S", timerec);
/* emit a detailed log message */
jk_log(l, JK_LOG_INFO,
"(%s) Request to (%s %s) started at %s",
ae->worker->name, r->method, r->req_uri, timestamp);
free(timerec);
free(timestamp);
}
The compiler wouldn't let me use an automatically-allocated char[32] so
I had to malloc it. I also had to convert from long to apr_time_exp_t
which required another structure/malloc as well.
Finally, I had to cast the r->ws_private to apache_private_data_t* which
required me to copy/paste the definition of apache_private_data_t from
mod_jk.h into jk_ajp_common.c -- just as a test for now.
Obviously, this works only for Apache httpd.
I have it running on one of my web servers for now -- hoping to catch an
error and see this additional logging to see if it's helpful to me. (LOL
just segfaulted; time to go back and look.)
What would be the best way to get the "start time" of the request in a
platform-independent way? Maybe just expand the jk_ws_service structure
to include it?
-chris
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