--- /dev/null
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mod_proxy.h"
+#include "scoreboard.h"
+#include "ap_mpm.h"
+#include "apr_version.h"
+#include "apr_hooks.h"
+
+module AP_MODULE_DECLARE_DATA lbmethod_bybusyness_module;
+
+static proxy_worker *find_best_bybusyness(proxy_balancer *balancer,
+ request_rec *r)
+{
+
+ int i;
+ proxy_worker *worker;
+ proxy_worker *mycandidate = NULL;
+ int cur_lbset = 0;
+ int max_lbset = 0;
+ int checking_standby;
+ int checked_standby;
+
+ int total_factor = 0;
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
+ "proxy: Entering bybusyness for BALANCER (%s)",
+ balancer->name);
+
+ /* First try to see if we have available candidate */
+ do {
+
+ checking_standby = checked_standby = 0;
+ while (!mycandidate && !checked_standby) {
+
+ worker = (proxy_worker *)balancer->workers->elts;
+ for (i = 0; i < balancer->workers->nelts; i++, worker++) {
+ if (!checking_standby) { /* first time through */
+ if (worker->s->lbset > max_lbset)
+ max_lbset = worker->s->lbset;
+ }
+
+ if (worker->s->lbset > cur_lbset)
+ continue;
+
+ if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
+ continue;
+
+ /* If the worker is in error state run
+ * retry on that worker. It will be marked as
+ * operational if the retry timeout is elapsed.
+ * The worker might still be unusable, but we try
+ * anyway.
+ */
+ if (!PROXY_WORKER_IS_USABLE(worker))
+ ap_proxy_retry_worker("BALANCER", worker, r->server);
+
+ /* Take into calculation only the workers that are
+ * not in error state or not disabled.
+ */
+ if (PROXY_WORKER_IS_USABLE(worker)) {
+
+ worker->s->lbstatus += worker->s->lbfactor;
+ total_factor += worker->s->lbfactor;
+
+ if (!mycandidate
+ || worker->s->busy < mycandidate->s->busy
+ || (worker->s->busy == mycandidate->s->busy && worker->s->lbstatus > mycandidate->s->lbstatus))
+ mycandidate = worker;
+
+ }
+
+ }
+
+ checked_standby = checking_standby++;
+
+ }
+
+ cur_lbset++;
+
+ } while (cur_lbset <= max_lbset && !mycandidate);
+
+ if (mycandidate) {
+ mycandidate->s->lbstatus -= total_factor;
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
+ "proxy: bybusyness selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d",
+ mycandidate->name, mycandidate->s->busy, mycandidate->s->lbstatus);
+
+ }
+
+ return mycandidate;
+
+}
+
+static const proxy_balancer_method bybusyness =
+{
+ "bybusyness",
+ &find_best_bybusyness,
+ NULL
+};
+
+
+static void register_hook(apr_pool_t *p)
+{
+ ap_register_provider(p, PROXY_LBMETHOD, "bybusyness", "0", &bybusyness);
+}
+
+module AP_MODULE_DECLARE_DATA lbmethod_bybusyness_module = {
+ STANDARD20_MODULE_STUFF,
+ NULL, /* create per-directory config structure */
+ NULL, /* merge per-directory config structures */
+ NULL, /* create per-server config structure */
+ NULL, /* merge per-server config structures */
+ NULL, /* command apr_table_t */
+ register_hook /* register hooks */
+};