Re: mod_proxy_ajp equivalent for JK_LB_ACTIVATION?
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Hash: SHA256
All,
Maybe I can earn myself a beer.
>> On 3/6/20 13:44, Rainer Jung wrote:
>>> no, the status unfortunately is not available as an Apache env
>>> var.
>
>>> mod_proxy_ajp has a builtin provision for automatic env var
>>> forwarding: alle env vars named AJP_SOMETHING will be
>>> forwarded as request attribute SOMETHING. But I see no easy way
>>> of detecting drain mode and setting an env var and there seems
>>> to be nothing builtin. I remember having added the forwarding
>>> for the LB activation to mod_jk many years ago but well after
>>> mod_proxy_ajp was done by Mladen. It seems to be one of the
>>> missing features in mod_proxy_ajp.
>
>> I'd of course want this to be available in mod_proxy_balancer so
>> any protocol would get it.
>
>>> But of course it could be added ...
In Apache 2.4.x, mod_proxy_balancer.c looks like this starting at line
636:
/* Add session info to env. */
apr_table_setn(r->subprocess_env,
"BALANCER_SESSION_STICKY", sticky);
apr_table_setn(r->subprocess_env,
"BALANCER_SESSION_ROUTE", route);
This seems like a great place to add:
apr_table_setn(r->subprocess_env,
"BALANCER_WORKER_STATUS", ???);
The question is "what should the '???' be?"
The local "proxy_worker **worker" is the place to start. It looks like
I can get the status bits using:
(*worker)->s->status
So I could either convert that into a char* (because the environment
works on strings) or use ap_proxy_parse_wstatus to convert the status
into a human-readable char*.
In either case, what's the proper way to handle memory management for
strings in httpd/mod_proxy/etc.?
There is the brute-force yet safe:
char *status = apr_table_get(r->subprocess_env,
"BALANCER_WORKER_STATUS");
if(NULL == status) {
free(status);
}
status = (char*)malloc(5 * sizeof char); // 4 characters is enough + \0
if(NULL != status) {
if(0 <= snprintf(status, 5, "%d", (*worker)->s->status)) {
apr_table_setn(r->subprocess_env,
"BALANCER_WORKER_STATUS", status);
} else {
apr_table_unset(r->subprocess_env,
"BALANCER_WORKER_STATUS");
free(status);
}
} else {
apr_table_unset(r->subprocess_env,
"BALANCER_WORKER_STATUS");
}
This is a little wasteful, as it re-allocates a 5-byte buffer for
every request. I can get away with a /single/ allocation if I
understand the worker lifecycle a little better.
Is this moving toward the right approach?
Other thoughts:
* Would hex be a better representation?
* Would a spelled-out version be better? It looks like
ap_proxy_parse_wstatus will generate a string like "ONH".
- How to handle memory management of the return value?
(Is this what the apt_pool_r* is being passed-around for?)
Thanks,
- -chris
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Re: mod_proxy_ajp equivalent for JK_LB_ACTIVATION?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 All, https://bz.apache.org/bugzilla/show_bug.cgi?id=64338 For anyone who likes beer. Or whatever you like to drink (within reason) . - -chris On 3/9/20 17:44, Christopher Schultz wrote: > Rainer, > > On 3/6/20 13:44, Rainer Jung wrote: >> Hi Chris, > >> no, the status unfortunately is not available as an Apache env >> var. > >> mod_proxy_ajp has a builtin provision for automatic env var >> forwarding: alle env vars named AJP_SOMETHING will be forwarded >> as request attribute SOMETHING. But I see no easy way of >> detecting drain mode and setting an env var and there seems to be >> nothing builtin. I remember having added the forwarding for the >> LB activation to mod_jk many years ago but well after >> mod_proxy_ajp was done by Mladen. It seems to be one of the >> missing features in mod_proxy_ajp. > > I'd of course want this to be available in mod_proxy_balancer so > any protocol would get it. > >> But of course it could be added ... > > :) > > I'll happily buy a round of drinks at ApacheCon if someone would > look into this. Without it, my "how to easily move from mod_jk to > mod_proxy_http" presentation is going to have a bit of a hole in > it. :( > > Thanks, -chris > >> Am 06.03.2020 um 16:34 schrieb Christopher Schultz: >>> -BEGIN PGP SIGNED MESSAGE- Hash: SHA256 >>> >>> All, >>> >>> At $work, we use mod_jk for proxying and I'd like to move to >>> mod_proxy_ajp with an eye toward moving to mod_proxy_http >>> eventually. >>> >>> We use the JK_LB_ACTIVATION state to perform load-balanced >>> node-draining[1] for maintenance and I'm trying to find out >>> how to get mod_proxy to give me its current status. >>> >>> I don't see anything in the documentation for >>> mod_proxy_balancer or mod_proxy_ajp. >>> >>> - From the balancer-manager, I can see that there are several >>> items of status metadata that might be useful: >>> >>> - - worker "draining mode" - - worker "disabled" state - - >>> worker "hot standby" state - - worker "stopped" state >>> >>> Each worker has a "status" value, which can be any of >>> D/S/I/R/H/E/N but it also looks like each of those can be set >>> independently. So the worker can be in "hot standby" + "error" >>> states. Hmm. >>> >>> Is that state available in an environment variable I can >>> forward-over to the origin node? >>> >>> - -chris > >> - > >> > > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org > > -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl6QrhIACgkQHPApP6U8 pFgBahAAhXGUNBAobLyBRgT3BtY+x9OrFVS5DnG1sMzJSej9V6wEm003Q83GSlB1 eTrC9wcJM2vuqiC+eZc2u5ruWDpsUnt/FxiU16URAjtXqwbbSg+LZ1qmtqkX7l6J eSE2NuEKHxeB0JoqFwxfpDI5uaulVJCb71bQzh/xQEbCbKLwt0uQVJ8h/z2XmfEh nYhhmY2spmfCsdMl0l+pnqjXAjQ70qK36JRNlGGlIkHD111BsOtN41vlg3WlCQ/v jpHqmB0b2Y7VwiQjXBDCXuwZxQ69+1FGoo7TQ1TAmb5YQzL8iSJ45Pzz9DSiVO+j 3lSfDJG8pCGQIFSuX/FagMWWJHOR9ZF+11/n8B/iOLv3RAWsKfEJwTS1y+Xxurzw M/64nQyXmfAqladkLXAFwTWqtFeuLFKmN3taBvVgX73SQ89HXLiUpOjOyG6U1HO8 rvn7E/lIMPFGPUZGFUWXMKMns9lXaDsfI5T/DfPhSjLxO2fX6W4LpJpe2OAd3uhA LgPsCZENLxOpe5J9DKpeMygV9MwSZ3TJgyXTtOBmXs9nWJeY83dy7PHNGad/Jpcp hpINTVMDp4cxvFSNz46dJ5Wkh9v3ss5esH8XglueaYUFzsf+/KqOvn3zrNKWdAqJ pgtAK0azSieW4oU7Ukn8nWUAwNl9LXastgzwKBuoJAMXAb7iIvw= =hiGB -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: mod_proxy_ajp equivalent for JK_LB_ACTIVATION?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Rainer, On 3/6/20 13:44, Rainer Jung wrote: > Hi Chris, > > no, the status unfortunately is not available as an Apache env > var. > > mod_proxy_ajp has a builtin provision for automatic env var > forwarding: alle env vars named AJP_SOMETHING will be forwarded as > request attribute SOMETHING. But I see no easy way of detecting > drain mode and setting an env var and there seems to be nothing > builtin. I remember having added the forwarding for the LB > activation to mod_jk many years ago but well after mod_proxy_ajp > was done by Mladen. It seems to be one of the missing features in > mod_proxy_ajp. I'd of course want this to be available in mod_proxy_balancer so any protocol would get it. > But of course it could be added ... :) I'll happily buy a round of drinks at ApacheCon if someone would look into this. Without it, my "how to easily move from mod_jk to mod_proxy_http" presentation is going to have a bit of a hole in it. :( Thanks, - -chris > Am 06.03.2020 um 16:34 schrieb Christopher Schultz: >> -BEGIN PGP SIGNED MESSAGE- Hash: SHA256 >> >> All, >> >> At $work, we use mod_jk for proxying and I'd like to move to >> mod_proxy_ajp with an eye toward moving to mod_proxy_http >> eventually. >> >> We use the JK_LB_ACTIVATION state to perform load-balanced >> node-draining[1] for maintenance and I'm trying to find out how >> to get mod_proxy to give me its current status. >> >> I don't see anything in the documentation for mod_proxy_balancer >> or mod_proxy_ajp. >> >> - From the balancer-manager, I can see that there are several >> items of status metadata that might be useful: >> >> - - worker "draining mode" - - worker "disabled" state - - worker >> "hot standby" state - - worker "stopped" state >> >> Each worker has a "status" value, which can be any of >> D/S/I/R/H/E/N but it also looks like each of those can be set >> independently. So the worker can be in "hot standby" + "error" >> states. Hmm. >> >> Is that state available in an environment variable I can >> forward-over to the origin node? >> >> - -chris > > - > > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl5muMEACgkQHPApP6U8 pFhNfw//c0JqDs7CQoCpc9u7eYZUU86yMr1Nlj/IXabIuyU0hfiwCWpmxpOgex+3 iPEXoO0qje0+lOW/D61FfzIJ+zZqIBJpq/e2MixLVntvfsDjfVpFZF7TpdHAwEfy rZx0k7ErNP3vNJT089sCyu7+XxPJocY5avk7b5va5z9TTOHNT136wqphRf4ka9yc AimmKhTNs3SsGiy7CJp47BXvyl5Nybhm5i1NkJF39oEXdiAVodUTThexjedTjwoi VESvX1K5A+ST5Zt8dw/teJmJPn3pV70LJz/JFnvTqIZ1aa0xB+niTqw/B4jTVW6W FUdnuRH9Z1choh7n9ipop62/suJpLaIwCXjm1n4iWKVhEDKntT1WtfUrp1BTr5UQ 3Z6BQX2TkAIVQ1rE3oMYbT7fSHCmEp86XQCg1tCm9cu9T2xlA4Ab09mpSrdEInQg +IPaUnvuHXmMghdULxjKuKGYGwdNTGfOTkLz9hMh3ghplZpZwg0lugba4+tN2z1y bp0pN+FaeSDTGwkF12xwSftr0+kt20WRO2l0MdbU9/xAQtf1tOgzH8CR1yxh1j0L YX3J8iHm7N6OzOL6vCbXDoYV0AL6KSbfeYboJu8fnvUEre6aw+ERz7RdWpaoGzYI uRO69QJpBE/fqoS7LIor4VTaFXU8khhO+KwwGObmfuYApT78Css= =jM3C -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: mod_proxy_ajp equivalent for JK_LB_ACTIVATION?
Hi Chris, no, the status unfortunately is not available as an Apache env var. mod_proxy_ajp has a builtin provision for automatic env var forwarding: alle env vars named AJP_SOMETHING will be forwarded as request attribute SOMETHING. But I see no easy way of detecting drain mode and setting an env var and there seems to be nothing builtin. I remember having added the forwarding for the LB activation to mod_jk many years ago but well after mod_proxy_ajp was done by Mladen. It seems to be one of the missing features in mod_proxy_ajp. But of course it could be added ... Regards, Rainer Am 06.03.2020 um 16:34 schrieb Christopher Schultz: -BEGIN PGP SIGNED MESSAGE- Hash: SHA256 All, At $work, we use mod_jk for proxying and I'd like to move to mod_proxy_ajp with an eye toward moving to mod_proxy_http eventually. We use the JK_LB_ACTIVATION state to perform load-balanced node-draining[1] for maintenance and I'm trying to find out how to get mod_proxy to give me its current status. I don't see anything in the documentation for mod_proxy_balancer or mod_proxy_ajp. - From the balancer-manager, I can see that there are several items of status metadata that might be useful: - - worker "draining mode" - - worker "disabled" state - - worker "hot standby" state - - worker "stopped" state Each worker has a "status" value, which can be any of D/S/I/R/H/E/N but it also looks like each of those can be set independently. So the worker can be in "hot standby" + "error" states. Hmm. Is that state available in an environment variable I can forward-over to the origin node? - -chris - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
mod_proxy_ajp equivalent for JK_LB_ACTIVATION?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 All, At $work, we use mod_jk for proxying and I'd like to move to mod_proxy_ajp with an eye toward moving to mod_proxy_http eventually. We use the JK_LB_ACTIVATION state to perform load-balanced node-draining[1] for maintenance and I'm trying to find out how to get mod_proxy to give me its current status. I don't see anything in the documentation for mod_proxy_balancer or mod_proxy_ajp. - From the balancer-manager, I can see that there are several items of status metadata that might be useful: - - worker "draining mode" - - worker "disabled" state - - worker "hot standby" state - - worker "stopped" state Each worker has a "status" value, which can be any of D/S/I/R/H/E/N but it also looks like each of those can be set independently. So the worker can be in "hot standby" + "error" states. Hmm. Is that state available in an environment variable I can forward-over to the origin node? - -chris -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl5ibZQACgkQHPApP6U8 pFgAnA//W4YL1edSOGE3P11DcgAbmAkemxi+h6gjM9oU54S5Yc+/3rwwg1Hxnnam t5PeAiO8OyEl3eq/Vr2gF87Xco04x1YEFmj844+TPC8VdGx5Em6hFWxFYBvLNY30 pzt2jKMVKUf+wdtZMvhT2uQYdtTxUbc3aVuCaaXBcR62ihAQ39CaRDalX2vr903Y 8fqT2YQXsYZlO0h6zX0vK37WB1DG4/iqYohcKKtEOvvwL9ZB5iMS40r+MqDulur+ 1q9WQPF25oemieC2G9pzRf014ftBdcnzJ5P7xQtWj5xy2b7+WQ7ZNlMyLNEc336K 1iVdM8AtyS4B2tax7hJIPDLlNQUUVTr1SAp1Jj6brEQFVFM+K0ilWjQnSWKBZdW1 lzs7KBzRTxDrsxl92G9cKBX3+2LqOLwjzWTwnjS7dA5P1mWvXGUkKuZLreaeyDod +WDjPhgK3lxAAXj+WP4NJPSrEbmzZZigN+Ad1BgRk0wsaXejudwYB1fvFnYMWHJC F9Ty16GlQGtaVI6aACeDX7zV2lO8kKXszKcPks0tZG7abpgom3s99WJvaeGfYEhh h+YC1Wjyym8EQdCjO0hQU1RiJvRifCuuJbI+DyupxsFEJLjM2zGSkaRYMEn9b2/V mkQeNPnsDCCr2NADdp1e0mRbAYUs9O0EsVrDs2wTKRw6HiUx1pk= =XKMA -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
