Commit 43474670 authored by Jim Jagielski's avatar Jim Jagielski
Browse files

Merge r417238, r437773, r446929, r453630 from trunk: 

* Add the following environment variables to expose the information
* about
  the route, the sticky session and the worker used during a request to
  other modules:

  BALANCER_SESSION_STICKY
  BALANCER_SESSION_ROUTE
  BALANCER_NAME
  BALANCER_WORKER_NAME
  BALANCER_WORKER_ROUTE

PR: 39806
Submitted by: Brian <brectanu gmail.com>
Reviewed by: rpluem


fix validation error


* Set the new environment variable BALANCER_ROUTE_CHANGED if a worker with a
  route different from the one supplied by the client had been chosen or if
  the client supplied no routing information for a balancer with sticky
  sessions.


* mod_proxy_balancer: Document BALANCER_ROUTE_CHANGED environment variable.

Submitted by: Brian Rectanus <brectanu gmail.com>
Reviewed by: rpluem

Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@472114 13f79535-47bb-0310-9956-ffa450edef68
parent e87fe625

CHANGES

+9 −0
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                                                        -*- coding: utf-8 -*-

Changes with Apache 2.2.4









  *) mod_proxy_balancer: Set the new environment variable BALANCER_ROUTE_CHANGED









     if a worker with a route different from the one supplied by the client









     had been chosen or if the client supplied no routing information for









     a balancer with sticky sessions. [Ruediger Pluem]

















  *) mod_proxy_balancer: Add information about the route, the sticky session









     and the worker used during a request as environment variables. PR 39806.









     [Brian <brectanu gmail.com>]

















  *) mod_proxy: Don't try to use dead backend connection. PR 37770.









     [Olivier BOEL <ob dorrboel.com>] 










































STATUS



+0
−16



























Changes for STATUS: 0 added lines, 16 removed lines.



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@@ -77,22 +77,6 @@ RELEASE SHOWSTOPPERS:







PATCHES ACCEPTED TO BACKPORT FROM TRUNK:









  [ start all new proposals below, under PATCHES PROPOSED. ]



















   * mod_proxy_balancer: Implement new environment variables









                         BALANCER_NAME









                         BALANCER_WORKER_NAME









                         BALANCER_WORKER_ROUTE









                         BALANCER_SESSION_STICKY









                         BALANCER_SESSION_ROUTE









                         BALANCER_ROUTE_CHANGED









      Trunk versions of patch:









        http://svn.apache.org/viewvc?view=rev&revision=417238 (including docs)









        http://svn.apache.org/viewvc?view=rev&revision=437773 (docs)









        http://svn.apache.org/viewvc?view=rev&revision=446929









        http://svn.apache.org/viewvc?view=rev&revision=453630 (docs)









      2.2.x version of patch:









        Trunk version works









      +1: rpluem, mturk, jim



















PATCHES PROPOSED TO BACKPORT FROM TRUNK:



















    * mpm_winnt: Fix return values from wait_for_many_objects.


































docs/manual/mod/mod_proxy_balancer.xml



+53
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Changes for docs/manual/mod/mod_proxy_balancer.xml: 53 added lines, 0 removed lines.



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@@ -271,6 +271,59 @@ candidate lbstatus -= total factor</code></pre>

















</section>



















<section id="environment">









    <title>Exported Environment Variables</title>









    <p>At present there are 6 environment variables exported:</p>



















    <dl>









    <!-- ============= BALANCER_SESSION_STICKY =============== -->









    <dt><var><a name="balancer_session_sticky" id="balancer_session_sticky">BALANCER_SESSION_STICKY</a></var></dt>









    <dd>









    <p>This is assigned the <var>stickysession</var> value used in the current









    request.  It is the cookie or parameter name used for sticky sessions</p>









    </dd>



















    <!-- ============= BALANCER_SESSION_ROUTE ================ -->









    <dt><var><a name="balancer_session_route" id="balancer_session_route">BALANCER_SESSION_ROUTE</a></var></dt>









    <dd>









    <p>This is assigned the <var>route</var> parsed from the current 









    request.</p>









    </dd>



















    <!-- ============= BALANCER_NAME ========================= -->









    <dt><var><a name="balancer_name" id="balancer_name">BALANCER_NAME</a></var></dt>









    <dd>









    <p>This is assigned the name of the balancer used for the current 









    request. The value is something like <code>balancer://foo</code>.</p>









    </dd>



















    <!-- ============= BALANCER_WORKER_NAME ================== -->









    <dt><var><a name="balancer_worker_name" id="balancer_worker_name">BALANCER_WORKER_NAME</a></var></dt>









    <dd>









    <p>This is assigned the name of the worker used for the current request.









    The value is something like <code>http://hostA:1234</code>.</p>









    </dd>



















    <!-- ============= BALANCER_WORKER_ROUTE ================= -->









    <dt><var><a name="balancer_worker_route" id="balancer_worker_route">BALANCER_WORKER_ROUTE</a></var></dt>









    <dd>









    <p>This is assigned the <var>route</var> of the worker that will be 









    used for the current request.</p>









    </dd>



















    <!-- ============= BALANCER_ROUTE_CHANGED ================= -->









    <dt><var><a name="balancer_route_changed" id="balancer_route_changed">BALANCER_ROUTE_CHANGED</a></var></dt>









    <dd>









    <p>This is set to 1 if the session route does not match the









    worker route (BALANCER_SESSION_ROUTE != BALANCER_WORKER_ROUTE) or the









    session does not yet have an established route.  This can be used to









    determine when/if the client needs to be sent an updated route









    when sticky sessions are used.</p>









    </dd>









    </dl>



















</section>



















<section id="enable">









    <title>Enabling Balancer Manager Support</title>









    <p>This module <em>requires</em> the service of 


































modules/proxy/mod_proxy_balancer.c



+35
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Changes for modules/proxy/mod_proxy_balancer.c: 35 added lines, 0 removed lines.



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@@ -260,6 +260,16 @@ static proxy_worker *find_session_route(proxy_balancer *balancer,







         * Find the worker that has this route defined.









         */









        worker = find_route_worker(balancer, *route, r);









        if (worker && strcmp(*route, worker->s->route)) {









            /*









             * Notice that the route of the worker chosen is different from









             * the route supplied by the client.









             */









            apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");









            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,









                         "proxy: BALANCER: Route changed from %s to %s",









                         *route, worker->s->route);









        }









        return worker;









    }









    else










@@ -417,9 +427,28 @@ static int proxy_balancer_pre_request(proxy_worker **worker,

















            return HTTP_SERVICE_UNAVAILABLE;









        }









        if ((*balancer)->sticky && runtime) {









            /*









             * This balancer has sticky sessions and the client either has not









             * supplied any routing information or all workers for this route









             * including possible redirect and hotstandby workers are in error









             * state, but we have found another working worker for this









             * balancer where we can send the request. Thus notice that we have









             * changed the route to the backend.









             */









            apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");









        }









        *worker = runtime;









    }



















    /* Add balancer/worker info to env. */









    apr_table_setn(r->subprocess_env,









                   "BALANCER_NAME", (*balancer)->name);









    apr_table_setn(r->subprocess_env,









                   "BALANCER_WORKER_NAME", (*worker)->name);









    apr_table_setn(r->subprocess_env,









                   "BALANCER_WORKER_ROUTE", (*worker)->s->route);



















    /* Rewrite the url from 'balancer://url'









     * to the 'worker_scheme://worker_hostname[:worker_port]/url'









     * This replaces the balancers fictional name with the










@@ -430,6 +459,12 @@ static int proxy_balancer_pre_request(proxy_worker **worker,







    if (route) {









        apr_table_setn(r->notes, "session-sticky", (*balancer)->sticky);









        apr_table_setn(r->notes, "session-route", route);



















        /* Add session info to env. */









        apr_table_setn(r->subprocess_env,









                       "BALANCER_SESSION_STICKY", (*balancer)->sticky);









        apr_table_setn(r->subprocess_env,









                       "BALANCER_SESSION_ROUTE", route);









    }









    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,









                 "proxy: BALANCER (%s) worker (%s) rewritten to %s",