136 lines
4.4 KiB
C
136 lines
4.4 KiB
C
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "mod_proxy.h"
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#include "scoreboard.h"
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#include "ap_mpm.h"
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#include "apr_version.h"
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#include "ap_hooks.h"
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module AP_MODULE_DECLARE_DATA lbmethod_bytraffic_module;
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static APR_OPTIONAL_FN_TYPE(proxy_balancer_get_best_worker)
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*ap_proxy_balancer_get_best_worker_fn = NULL;
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static int is_best_bytraffic(proxy_worker *current, proxy_worker *prev_best, void *baton)
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{
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apr_off_t *min_traffic = (apr_off_t *)baton;
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apr_off_t traffic = (current->s->transferred / current->s->lbfactor)
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+ (current->s->read / current->s->lbfactor);
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if (!prev_best || (traffic < *min_traffic)) {
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*min_traffic = traffic;
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return TRUE;
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}
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return FALSE;
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}
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/*
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* The idea behind the find_best_bytraffic scheduler is the following:
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*
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* We know the amount of traffic (bytes in and out) handled by each
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* worker. We normalize that traffic by each workers' weight. So assuming
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* a setup as below:
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*
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* worker a b c
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* lbfactor 1 1 3
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*
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* the scheduler will allow worker c to handle 3 times the
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* traffic of a and b. If each request/response results in the
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* same amount of traffic, then c would be accessed 3 times as
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* often as a or b. If, for example, a handled a request that
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* resulted in a large i/o bytecount, then b and c would be
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* chosen more often, to even things out.
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*/
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static proxy_worker *find_best_bytraffic(proxy_balancer *balancer,
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request_rec *r)
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{
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apr_off_t min_traffic = 0;
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return ap_proxy_balancer_get_best_worker_fn(balancer, r, is_best_bytraffic,
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&min_traffic);
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}
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/* assumed to be mutex protected by caller */
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static apr_status_t reset(proxy_balancer *balancer, server_rec *s)
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{
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int i;
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proxy_worker **worker;
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worker = (proxy_worker **)balancer->workers->elts;
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for (i = 0; i < balancer->workers->nelts; i++, worker++) {
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(*worker)->s->lbstatus = 0;
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(*worker)->s->busy = 0;
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(*worker)->s->transferred = 0;
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(*worker)->s->read = 0;
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}
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return APR_SUCCESS;
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}
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static apr_status_t age(proxy_balancer *balancer, server_rec *s)
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{
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return APR_SUCCESS;
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}
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static const proxy_balancer_method bytraffic =
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{
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"bytraffic",
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&find_best_bytraffic,
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NULL,
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&reset,
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&age,
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NULL
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};
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/* post_config hook: */
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static int lbmethod_bytraffic_post_config(apr_pool_t *pconf, apr_pool_t *plog,
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apr_pool_t *ptemp, server_rec *s)
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{
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/* lbmethod_bytraffic_post_config() will be called twice during startup. So, don't
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* set up the static data the 1st time through. */
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if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG) {
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return OK;
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}
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ap_proxy_balancer_get_best_worker_fn =
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APR_RETRIEVE_OPTIONAL_FN(proxy_balancer_get_best_worker);
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if (!ap_proxy_balancer_get_best_worker_fn) {
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ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(10150)
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"mod_proxy must be loaded for mod_lbmethod_bytraffic");
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return !OK;
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}
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return OK;
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}
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static void register_hook(apr_pool_t *p)
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{
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ap_register_provider(p, PROXY_LBMETHOD, "bytraffic", "0", &bytraffic);
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ap_hook_post_config(lbmethod_bytraffic_post_config, NULL, NULL, APR_HOOK_MIDDLE);
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}
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AP_DECLARE_MODULE(lbmethod_bytraffic) = {
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STANDARD20_MODULE_STUFF,
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NULL, /* create per-directory config structure */
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NULL, /* merge per-directory config structures */
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NULL, /* create per-server config structure */
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NULL, /* merge per-server config structures */
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NULL, /* command apr_table_t */
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register_hook /* register hooks */
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};
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