mod_proxy_balancer.c revision 50ebf0554e0878bf4e9ee9a3cb574f29323e9692
/* Copyright 1999-2005 The Apache Software Foundation or its licensors, as
* applicable.
*
* Licensed 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.
*/
/* Load balancer module for Apache proxy */
#define CORE_PRIVATE
#include "mod_proxy.h"
#include "ap_mpm.h"
#include "apr_version.h"
#include "apr_hooks.h"
module AP_MODULE_DECLARE_DATA proxy_balancer_module;
static int proxy_balancer_canon(request_rec *r, char *url)
{
char *host, *path, *search;
const char *err;
apr_port_t port = 0;
if (strncasecmp(url, "balancer:", 9) == 0) {
url += 9;
}
else {
return DECLINED;
}
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: BALANCER: canonicalising URL %s", url);
/* do syntatic check.
* We break the URL into host, port, path, search
*/
err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
if (err) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
"error parsing URL %s: %s",
url, err);
return HTTP_BAD_REQUEST;
}
/* now parse path/search args, according to rfc1738 */
/* N.B. if this isn't a true proxy request, then the URL _path_
* has already been decoded. True proxy requests have r->uri
* == r->unparsed_uri, and no others have that property.
*/
if (r->uri == r->unparsed_uri) {
search = strchr(url, '?');
if (search != NULL)
*(search++) = '\0';
}
else
search = r->args;
/* process path */
path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0, r->proxyreq);
if (path == NULL)
return HTTP_BAD_REQUEST;
r->filename = apr_pstrcat(r->pool, "proxy:balancer://", host,
"/", path, (search) ? "?" : "", (search) ? search : "", NULL);
return OK;
}
static int init_balancer_members(proxy_server_conf *conf, server_rec *s,
proxy_balancer *balancer)
{
int i;
proxy_worker *workers;
workers = (proxy_worker *)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++) {
ap_proxy_initialize_worker_share(conf, workers, s);
workers->s->status = PROXY_WORKER_INITIALIZED;
++workers;
}
workers = (proxy_worker *)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++) {
/* Set to the original configuration */
workers[i].s->lbstatus = workers[i].s->lbfactor =
(workers[i].lbfactor ? workers[i].lbfactor : 1);
}
/* Set default number of attempts to the number of
* workers.
*/
if (!balancer->max_attempts_set && balancer->workers->nelts > 1) {
balancer->max_attempts = balancer->workers->nelts - 1;
balancer->max_attempts_set = 1;
}
return 0;
}
/* Retrieve the parameter with the given name
* Something like 'JSESSIONID=12345...N'
*/
static char *get_path_param(apr_pool_t *pool, char *url,
const char *name)
{
char *path = NULL;
for (path = strstr(url, name); path; path = strstr(path + 1, name)) {
path += (strlen(name) + 1);
if (*path == '=') {
/*
* Session path was found, get it's value
*/
++path;
if (strlen(path)) {
char *q;
path = apr_pstrdup(pool, path);
if ((q = strchr(path, '?')))
*q = '\0';
return path;
}
}
}
return NULL;
}
static char *get_cookie_param(request_rec *r, const char *name)
{
const char *cookies;
const char *start_cookie;
if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
for (start_cookie = ap_strstr_c(cookies, name); start_cookie;
start_cookie = ap_strstr_c(start_cookie + 1, name)) {
if (start_cookie == cookies ||
start_cookie[-1] == ';' ||
start_cookie[-1] == ',' ||
isspace(start_cookie[-1])) {
start_cookie += strlen(name);
while(*start_cookie && isspace(*start_cookie))
++start_cookie;
if (*start_cookie == '=' && start_cookie[1]) {
/*
* Session cookie was found, get it's value
*/
char *end_cookie, *cookie;
++start_cookie;
cookie = apr_pstrdup(r->pool, start_cookie);
if ((end_cookie = strchr(cookie, ';')) != NULL)
*end_cookie = '\0';
if((end_cookie = strchr(cookie, ',')) != NULL)
*end_cookie = '\0';
return cookie;
}
}
}
}
return NULL;
}
/* Find the worker that has the 'route' defined
*/
static proxy_worker *find_route_worker(proxy_balancer *balancer,
const char *route)
{
int i;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++) {
if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
return worker;
}
worker++;
}
return NULL;
}
static proxy_worker *find_session_route(proxy_balancer *balancer,
request_rec *r,
char **route,
char **url)
{
if (!balancer->sticky)
return NULL;
/* Try to find the sticky route inside url */
*route = get_path_param(r->pool, *url, balancer->sticky);
if (!*route)
*route = get_cookie_param(r, balancer->sticky);
if (*route) {
/* We have a route in path or in cookie
* Find the worker that has this route defined.
*/
proxy_worker *worker = find_route_worker(balancer, *route);
if (worker && !PROXY_WORKER_IS_USABLE(worker)) {
/* We have a worker that is unusable.
* It can be in error or disabled, but in case
* it has a redirection set use that redirection worker.
* This enables to safely remove the member from the
* balancer. Of course you will need a some kind of
* session replication between those two remote.
*/
if (*worker->s->redirect)
worker = find_route_worker(balancer, worker->s->redirect);
/* Check if the redirect worker is usable */
if (worker && !PROXY_WORKER_IS_USABLE(worker))
worker = NULL;
}
return worker;
}
else
return NULL;
}
static proxy_worker *find_best_worker(proxy_balancer *balancer,
request_rec *r)
{
proxy_worker *candidate = NULL;
if (PROXY_THREAD_LOCK(balancer) != APR_SUCCESS)
return NULL;
candidate = (*balancer->lbmethod->finder)(balancer, r);
/*
PROXY_THREAD_UNLOCK(balancer);
return NULL;
*/
PROXY_THREAD_UNLOCK(balancer);
if (candidate == NULL) {
/* All the workers are in error state or disabled.
* If the balancer has a timeout sleep for a while
* and try again to find the worker. The chances are
* that some other thread will release a connection.
* By default the timeout is not set, and the server
* returns SERVER_BUSY.
*/
#if APR_HAS_THREADS
if (balancer->timeout) {
/* XXX: This can perhaps be build using some
* smarter mechanism, like tread_cond.
* But since the statuses can came from
* different childs, use the provided algo.
*/
apr_interval_time_t timeout = balancer->timeout;
apr_interval_time_t step, tval = 0;
/* Set the timeout to 0 so that we don't
* end in infinite loop
*/
balancer->timeout = 0;
step = timeout / 100;
while (tval < timeout) {
apr_sleep(step);
/* Try again */
if ((candidate = find_best_worker(balancer, r)))
break;
tval += step;
}
/* restore the timeout */
balancer->timeout = timeout;
}
#endif
}
return candidate;
}
static int rewrite_url(request_rec *r, proxy_worker *worker,
char **url)
{
const char *scheme = strstr(*url, "://");
const char *path = NULL;
if (scheme)
path = ap_strchr_c(scheme + 3, '/');
/* we break the URL into host, port, uri */
if (!worker) {
return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
"missing worker. URI cannot be parsed: ", *url,
NULL));
}
*url = apr_pstrcat(r->pool, worker->name, path, NULL);
return OK;
}
static int proxy_balancer_pre_request(proxy_worker **worker,
proxy_balancer **balancer,
request_rec *r,
proxy_server_conf *conf, char **url)
{
int access_status;
proxy_worker *runtime;
char *route = NULL;
apr_status_t rv;
*worker = NULL;
/* Step 1: check if the url is for us
* The url we can handle starts with 'balancer://'
* If balancer is already provided skip the search
* for balancer, because this is failover attempt.
*/
if (!*balancer &&
!(*balancer = ap_proxy_get_balancer(r->pool, conf, *url)))
return DECLINED;
/* Step 2: find the session route */
runtime = find_session_route(*balancer, r, &route, url);
/* Lock the LoadBalancer
* XXX: perhaps we need the process lock here
*/
if ((rv = PROXY_THREAD_LOCK(*balancer)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
"proxy: BALANCER: lock");
return DECLINED;
}
if (runtime) {
int i, total_factor = 0;
proxy_worker *workers;
/* We have a sticky load balancer
* Update the workers status
* so that even session routes get
* into account.
*/
workers = (proxy_worker *)(*balancer)->workers->elts;
for (i = 0; i < (*balancer)->workers->nelts; i++) {
/* Take into calculation only the workers that are
* not in error state or not disabled.
*/
if (PROXY_WORKER_IS_USABLE(workers)) {
workers->s->lbstatus += workers->s->lbfactor;
total_factor += workers->s->lbfactor;
}
workers++;
}
runtime->s->lbstatus -= total_factor;
runtime->s->elected++;
*worker = runtime;
}
else if (route && (*balancer)->sticky_force) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
"proxy: BALANCER: (%s). All workers are in error state for route (%s)",
(*balancer)->name, route);
PROXY_THREAD_UNLOCK(*balancer);
return HTTP_SERVICE_UNAVAILABLE;
}
PROXY_THREAD_UNLOCK(*balancer);
if (!*worker) {
runtime = find_best_worker(*balancer, r);
if (!runtime) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
"proxy: BALANCER: (%s). All workers are in error state",
(*balancer)->name);
return HTTP_SERVICE_UNAVAILABLE;
}
*worker = runtime;
}
/* Rewrite the url from 'balancer://url'
* to the 'worker_scheme://worker_hostname[:worker_port]/url'
* This replaces the balancers fictional name with the
* real hostname of the elected worker.
*/
access_status = rewrite_url(r, *worker, url);
/* Add the session route to request notes if present */
if (route) {
apr_table_setn(r->notes, "session-sticky", (*balancer)->sticky);
apr_table_setn(r->notes, "session-route", route);
}
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: BALANCER (%s) worker (%s) rewritten to %s",
(*balancer)->name, (*worker)->name, *url);
return access_status;
}
static int proxy_balancer_post_request(proxy_worker *worker,
proxy_balancer *balancer,
request_rec *r,
proxy_server_conf *conf)
{
apr_status_t rv;
if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
"proxy: BALANCER: lock");
return HTTP_INTERNAL_SERVER_ERROR;
}
/* TODO: calculate the bytes transferred
* This will enable to elect the worker that has
* the lowest load.
* The bytes transferred depends on the protocol
* used, so each protocol handler should keep the
* track on that.
*/
PROXY_THREAD_UNLOCK(balancer);
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy_balancer_post_request for (%s)", balancer->name);
return OK;
}
static void recalc_factors(proxy_balancer *balancer)
{
int i;
proxy_worker *workers;
/* Recalculate lbfactors */
workers = (proxy_worker *)balancer->workers->elts;
/* Special case if there is only one worker it's
* load factor will always be 1
*/
if (balancer->workers->nelts == 1) {
workers->s->lbstatus = workers->s->lbfactor = 1;
return;
}
for (i = 0; i < balancer->workers->nelts; i++) {
/* Update the status entries */
workers[i].s->lbstatus = workers[i].s->lbfactor;
}
}
/* Manages the loadfactors and member status
*/
static int balancer_handler(request_rec *r)
{
void *sconf = r->server->module_config;
proxy_server_conf *conf = (proxy_server_conf *)
ap_get_module_config(sconf, &proxy_module);
proxy_balancer *balancer, *bsel = NULL;
proxy_worker *worker, *wsel = NULL;
apr_table_t *params = apr_table_make(r->pool, 10);
int access_status;
int i, n;
const char *name;
/* is this for us? */
if (strcmp(r->handler, "balancer-manager"))
return DECLINED;
r->allowed = (AP_METHOD_BIT << M_GET);
if (r->method_number != M_GET)
return DECLINED;
if (r->args) {
char *args = apr_pstrdup(r->pool, r->args);
char *tok, *val;
while (args && *args) {
if ((val = ap_strchr(args, '='))) {
*val++ = '\0';
if ((tok = ap_strchr(val, '&')))
*tok++ = '\0';
if ((access_status = ap_unescape_url(val)) != OK)
return access_status;
apr_table_setn(params, args, val);
args = tok;
}
else
return HTTP_BAD_REQUEST;
}
}
if ((name = apr_table_get(params, "b")))
bsel = ap_proxy_get_balancer(r->pool, conf,
apr_pstrcat(r->pool, "balancer://", name, NULL));
if ((name = apr_table_get(params, "w"))) {
const char *sc = apr_table_get(params, "s");
char *asname = NULL;
proxy_worker *ws = NULL;
if (sc) {
asname = apr_pstrcat(r->pool, sc, "://", name, NULL);
ws = ap_proxy_get_worker(r->pool, conf, asname);
}
if (ws) {
worker = (proxy_worker *)bsel->workers->elts;
for (n = 0; n < bsel->workers->nelts; n++) {
if (strcasecmp(worker->name, ws->name) == 0) {
wsel = worker;
break;
}
++worker;
}
}
}
/* First set the params */
if (bsel) {
const char *val;
if ((val = apr_table_get(params, "ss"))) {
if (strlen(val))
bsel->sticky = apr_pstrdup(conf->pool, val);
else
bsel->sticky = NULL;
}
if ((val = apr_table_get(params, "tm"))) {
int ival = atoi(val);
if (ival >= 0)
bsel->timeout = apr_time_from_sec(ival);
}
if ((val = apr_table_get(params, "fa"))) {
int ival = atoi(val);
if (ival >= 0)
bsel->max_attempts = ival;
bsel->max_attempts_set = 1;
}
if ((val = apr_table_get(params, "lm"))) {
struct proxy_balancer_method *ent =
(struct proxy_balancer_method *) conf->lbmethods->elts;
int i;
for (i = 0; i < conf->lbmethods->nelts; i++) {
if (!strcasecmp(val, ent->name)) {
bsel->lbmethod = ent;
break;
}
ent++;
}
}
}
if (wsel) {
const char *val;
if ((val = apr_table_get(params, "lf"))) {
int ival = atoi(val);
if (ival >= 1 && ival <= 100) {
wsel->s->lbfactor = ival;
if (bsel)
recalc_factors(bsel);
}
}
if ((val = apr_table_get(params, "wr"))) {
if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
strcpy(wsel->s->route, val);
else
*wsel->s->route = '\0';
}
if ((val = apr_table_get(params, "rr"))) {
if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
strcpy(wsel->s->redirect, val);
else
*wsel->s->redirect = '\0';
}
if ((val = apr_table_get(params, "dw"))) {
if (!strcasecmp(val, "Disable"))
wsel->s->status |= PROXY_WORKER_DISABLED;
else if (!strcasecmp(val, "Enable"))
wsel->s->status &= ~PROXY_WORKER_DISABLED;
}
}
if (apr_table_get(params, "xml")) {
ap_set_content_type(r, "text/xml");
ap_rputs("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n", r);
ap_rputs("<httpd:manager xmlns:httpd=\"http://httpd.apache.org\">\n", r);
ap_rputs(" <httpd:balancers>\n", r);
balancer = (proxy_balancer *)conf->balancers->elts;
for (i = 0; i < conf->balancers->nelts; i++) {
ap_rputs(" <httpd:balancer>\n", r);
ap_rvputs(r, " <httpd:name>", balancer->name, "</httpd:name>\n", NULL);
ap_rputs(" <httpd:workers>\n", r);
worker = (proxy_worker *)balancer->workers->elts;
for (n = 0; n < balancer->workers->nelts; n++) {
ap_rputs(" <httpd:worker>\n", r);
ap_rvputs(r, " <httpd:scheme>", worker->scheme,
"</httpd:scheme>\n", NULL);
ap_rvputs(r, " <httpd:hostname>", worker->hostname,
"</httpd:hostname>\n", NULL);
ap_rprintf(r, " <httpd:loadfactor>%d</httpd:loadfactor>\n",
worker->s->lbfactor);
ap_rputs(" </httpd:worker>\n", r);
++worker;
}
ap_rputs(" </httpd:workers>\n", r);
ap_rputs(" </httpd:balancer>\n", r);
++balancer;
}
ap_rputs(" </httpd:balancers>\n", r);
ap_rputs("</httpd:manager>", r);
}
else {
ap_set_content_type(r, "text/html");
ap_rputs(DOCTYPE_HTML_3_2
"<html><head><title>Balancer Manager</title></head>\n", r);
ap_rputs("<body><h1>Load Balancer Manager for ", r);
ap_rvputs(r, ap_get_server_name(r), "</h1>\n\n", NULL);
ap_rvputs(r, "<dl><dt>Server Version: ",
ap_get_server_version(), "</dt>\n", NULL);
ap_rvputs(r, "<dt>Server Built: ",
ap_get_server_built(), "\n</dt></dl>\n", NULL);
balancer = (proxy_balancer *)conf->balancers->elts;
for (i = 0; i < conf->balancers->nelts; i++) {
ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
ap_rvputs(r, "<a href=\"", r->uri, "?b=",
balancer->name + sizeof("balancer://") - 1,
"\">", NULL);
ap_rvputs(r, balancer->name, "</a></h3>\n\n", NULL);
ap_rputs("\n\n<table border=\"0\"><tr>"
"<th>StickySession</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
"</tr>\n<tr>", r);
ap_rvputs(r, "<td>", balancer->sticky, NULL);
ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
apr_time_sec(balancer->timeout));
ap_rprintf(r, "<td>%d</td>\n", balancer->max_attempts);
ap_rprintf(r, "<td>%s</td>\n",
balancer->lbmethod->name);
ap_rputs("</table>\n", r);
ap_rputs("\n\n<table border=\"0\"><tr>"
"<th>Scheme</th><th>Host</th>"
"<th>Route</th><th>RouteRedir</th>"
"<th>Factor</th><th>Status</th>"
"</tr>\n", r);
worker = (proxy_worker *)balancer->workers->elts;
for (n = 0; n < balancer->workers->nelts; n++) {
ap_rvputs(r, "<tr>\n<td>", worker->scheme, "</td><td>", NULL);
ap_rvputs(r, "<a href=\"", r->uri, "?b=",
balancer->name + sizeof("balancer://") - 1,
"&s=", worker->scheme, "&w=", worker->hostname,
"\">", NULL);
ap_rvputs(r, worker->hostname, "</a></td>", NULL);
ap_rvputs(r, "<td>", worker->s->route, NULL);
ap_rvputs(r, "</td><td>", worker->s->redirect, NULL);
ap_rprintf(r, "</td><td>%d</td><td>", worker->s->lbfactor);
if (worker->s->status & PROXY_WORKER_DISABLED)
ap_rputs("Dis", r);
else if (worker->s->status & PROXY_WORKER_IN_ERROR)
ap_rputs("Err", r);
else if (worker->s->status & PROXY_WORKER_INITIALIZED)
ap_rputs("Ok", r);
else
ap_rputs("-", r);
ap_rputs("</td></tr>\n", r);
++worker;
}
ap_rputs("</table>\n", r);
++balancer;
}
ap_rputs("<hr />\n", r);
if (wsel && bsel) {
ap_rputs("<h3>Edit worker settings for ", r);
ap_rvputs(r, wsel->name, "</h3>\n", NULL);
ap_rvputs(r, "<form method=\"GET\" action=\"", NULL);
ap_rvputs(r, r->uri, "\">\n<dl>", NULL);
ap_rputs("<table><tr><td>Load factor:</td><td><input name=\"lf\" type=text ", r);
ap_rprintf(r, "value=\"%d\"></td><tr>\n", wsel->s->lbfactor);
ap_rputs("<tr><td>Route:</td><td><input name=\"wr\" type=text ", r);
ap_rvputs(r, "value=\"", wsel->route, NULL);
ap_rputs("\"></td><tr>\n", r);
ap_rputs("<tr><td>Route Redirect:</td><td><input name=\"rr\" type=text ", r);
ap_rvputs(r, "value=\"", wsel->redirect, NULL);
ap_rputs("\"></td><tr>\n", r);
ap_rputs("<tr><td>Status:</td><td>Disabled: <input name=\"dw\" value=\"Disable\" type=radio", r);
if (wsel->s->status & PROXY_WORKER_DISABLED)
ap_rputs(" checked", r);
ap_rputs("> | Enabled: <input name=\"dw\" value=\"Enable\" type=radio", r);
if (!(wsel->s->status & PROXY_WORKER_DISABLED))
ap_rputs(" checked", r);
ap_rputs("></td><tr>\n", r);
ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
ap_rvputs(r, "</table>\n<input type=hidden name=\"s\" ", NULL);
ap_rvputs(r, "value=\"", wsel->scheme, "\">\n", NULL);
ap_rvputs(r, "<input type=hidden name=\"w\" ", NULL);
ap_rvputs(r, "value=\"", wsel->hostname, "\">\n", NULL);
ap_rvputs(r, "<input type=hidden name=\"b\" ", NULL);
ap_rvputs(r, "value=\"", bsel->name + sizeof("balancer://") - 1,
"\">\n</form>\n", NULL);
ap_rputs("<hr />\n", r);
}
else if (bsel) {
ap_rputs("<h3>Edit balancer settings for ", r);
ap_rvputs(r, bsel->name, "</h3>\n", NULL);
ap_rvputs(r, "<form method=\"GET\" action=\"", NULL);
ap_rvputs(r, r->uri, "\">\n<dl>", NULL);
ap_rputs("<table><tr><td>StickySession Identifier:</td><td><input name=\"ss\" type=text ", r);
if (bsel->sticky)
ap_rvputs(r, "value=\"", bsel->sticky, "\"", NULL);
ap_rputs("></td><tr>\n<tr><td>Timeout:</td><td><input name=\"tm\" type=text ", r);
ap_rprintf(r, "value=\"%" APR_TIME_T_FMT "\"></td></tr>\n",
apr_time_sec(bsel->timeout));
ap_rputs("<tr><td>Failover Attempts:</td><td><input name=\"fa\" type=text ", r);
ap_rprintf(r, "value=\"%d\"></td></tr>\n",
bsel->max_attempts);
ap_rputs("<tr><td>LB Method:</td><td><select name=\"lm\">", r);
{
struct proxy_balancer_method *ent =
(struct proxy_balancer_method *) conf->lbmethods->elts;
int i;
for (i = 0; i < conf->lbmethods->nelts; i++) {
ap_rprintf(r, "<option value=\"%s\" %s>%s</option>", ent->name,
(!strcasecmp(bsel->lbmethod->name, ent->name)) ? "selected" : "",
ent->name);
ent++;
}
}
ap_rputs("</select></td></tr>\n", r);
ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
ap_rvputs(r, "</table>\n<input type=hidden name=\"b\" ", NULL);
ap_rvputs(r, "value=\"", bsel->name + sizeof("balancer://") - 1,
"\">\n</form>\n", NULL);
ap_rputs("<hr />\n", r);
}
ap_rputs(ap_psignature("",r), r);
ap_rputs("</body></html>\n", r);
}
return OK;
}
static void child_init(apr_pool_t *p, server_rec *s)
{
while (s) {
void *sconf = s->module_config;
proxy_server_conf *conf;
proxy_balancer *balancer;
int i;
conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
/* Initialize shared scoreboard data */
balancer = (proxy_balancer *)conf->balancers->elts;
for (i = 0; i < conf->balancers->nelts; i++) {
init_balancer_members(conf, s, balancer);
balancer++;
}
s = s->next;
}
}
static void ap_proxy_balancer_register_hook(apr_pool_t *p)
{
/* Only the mpm_winnt has child init hook handler.
* make sure that we are called after the mpm
* initializes and after the mod_proxy
*/
static const char *const aszPred[] = { "mpm_winnt.c", "mod_proxy.c", NULL};
/* manager handler */
ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
ap_hook_child_init(child_init, aszPred, NULL, APR_HOOK_MIDDLE);
proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
}
module AP_MODULE_DECLARE_DATA proxy_balancer_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 */
ap_proxy_balancer_register_hook /* register hooks */
};