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simple, functional interface to add additional balancer lb selection methods

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without requiring code changes to mod_proxy/mod_proxy_balancer;
these can be implemented via sub-modules now.

Let the games begin...


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@232282 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Jim Jagielski
2005-08-12 12:47:04 +00:00
parent 5d7d8f280f
commit a7d488a6d2
5 changed files with 134 additions and 57 deletions
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5
CHANGES
View File

@@ -1,6 +1,11 @@
-*- coding: utf-8 -*-
Changes with Apache 2.3.0
*) mod_proxy/mod_proxy_balancer: Provide a simple, functional
interface to add additional balancer lb selection methods
without requiring code changes to mod_proxy/mod_proxy_balancer;
these can be implemented via sub-modules now. [Jim Jagielski]
*) mod_cache: Fix incorrectly served 304 responses when expired cache
entity is valid, but cache is unwritable and headers cannot be
updated. [Colm MacCarthaigh <colm stdlib.net>]

39
modules/proxy/mod_proxy.c
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@@ -224,7 +224,8 @@ static const char *set_worker_param(apr_pool_t *p,
return NULL;
}
static const char *set_balancer_param(apr_pool_t *p,
static const char *set_balancer_param(proxy_server_conf *conf,
apr_pool_t *p,
proxy_balancer *balancer,
const char *key,
const char *val)
@@ -272,13 +273,17 @@ static const char *set_balancer_param(apr_pool_t *p,
balancer->max_attempts_set = 1;
}
else if (!strcasecmp(key, "lbmethod")) {
/* Which LB scheduler method */
if (!strcasecmp(val, "traffic"))
balancer->lbmethod = lbmethod_traffic;
else if (!strcasecmp(val, "requests"))
balancer->lbmethod = lbmethod_requests;
else
return "lbmethod must be Traffic|Requests";
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)) {
balancer->lbmethod = ent;
return NULL;
}
ent++;
}
return "unknown lbmethod";
}
else {
return "unknown Balancer parameter";
@@ -793,6 +798,7 @@ static void * create_proxy_config(apr_pool_t *p, server_rec *s)
ps->allowed_connect_ports = apr_array_make(p, 10, sizeof(int));
ps->workers = apr_array_make(p, 10, sizeof(proxy_worker));
ps->balancers = apr_array_make(p, 10, sizeof(proxy_balancer));
ps->lbmethods = apr_array_make(p, 10, sizeof(proxy_balancer_method));
ps->forward = NULL;
ps->reverse = NULL;
ps->domain = NULL;
@@ -815,6 +821,9 @@ static void * create_proxy_config(apr_pool_t *p, server_rec *s)
ps->badopt = bad_error;
ps->badopt_set = 0;
ps->pool = p;
proxy_run_load_lbmethods(ps);
return ps;
}
@@ -832,6 +841,7 @@ static void * merge_proxy_config(apr_pool_t *p, void *basev, void *overridesv)
ps->allowed_connect_ports = apr_array_append(p, base->allowed_connect_ports, overrides->allowed_connect_ports);
ps->workers = apr_array_append(p, base->workers, overrides->workers);
ps->balancers = apr_array_append(p, base->balancers, overrides->balancers);
ps->lbmethods = apr_array_append(p, base->lbmethods, overrides->lbmethods);
ps->forward = overrides->forward ? overrides->forward : base->forward;
ps->reverse = overrides->reverse ? overrides->reverse : base->reverse;
@@ -1021,7 +1031,7 @@ static const char *
return apr_pstrcat(cmd->temp_pool, "ProxyPass ", err, NULL);
}
for (i = 0; i < arr->nelts; i++) {
const char *err = set_balancer_param(cmd->pool, balancer, elts[i].key,
const char *err = set_balancer_param(conf, cmd->pool, balancer, elts[i].key,
elts[i].val);
if (err)
return apr_pstrcat(cmd->temp_pool, "ProxyPass ", err, NULL);
@@ -1509,7 +1519,7 @@ static const char *
if (worker)
err = set_worker_param(cmd->pool, worker, word, val);
else
err = set_balancer_param(cmd->pool, balancer, word, val);
err = set_balancer_param(conf, cmd->pool, balancer, word, val);
if (err)
return apr_pstrcat(cmd->temp_pool, "ProxySet ", err, " ", word, " ", name, NULL);
@@ -1754,9 +1764,7 @@ static int proxy_status_hook(request_rec *r, int flags)
ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
apr_time_sec(balancer->timeout));
ap_rprintf(r, "<td>%s</td>\n",
balancer->lbmethod == lbmethod_requests ? "Requests" :
balancer->lbmethod == lbmethod_traffic ? "Traffic" :
"Unknown");
balancer->lbmethod->name);
ap_rputs("</table>\n", r);
ap_rputs("\n\n<table border=\"0\"><tr>"
"<th>Sch</th><th>Host</th><th>Stat</th>"
@@ -1917,6 +1925,7 @@ APR_HOOK_STRUCT(
APR_HOOK_LINK(canon_handler)
APR_HOOK_LINK(pre_request)
APR_HOOK_LINK(post_request)
APR_HOOK_LINK(load_lbmethods)
APR_HOOK_LINK(request_status)
)
@@ -1942,6 +1951,10 @@ APR_IMPLEMENT_EXTERNAL_HOOK_RUN_FIRST(proxy, PROXY, int, post_request,
request_rec *r,
proxy_server_conf *conf),(worker,
balancer,r,conf),DECLINED)
APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(proxy, PROXY, int, load_lbmethods,
(proxy_server_conf *conf),
(conf),
OK, DECLINED)
APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(proxy, PROXY, int, fixups,
(request_rec *r), (r),
OK, DECLINED)

25
modules/proxy/mod_proxy.h
View File

@@ -120,6 +120,7 @@ struct noproxy_entry {
typedef struct proxy_balancer proxy_balancer;
typedef struct proxy_worker proxy_worker;
typedef struct proxy_conn_pool proxy_conn_pool;
typedef struct proxy_balancer_method proxy_balancer_method;
typedef struct {
apr_array_header_t *proxies;
@@ -179,6 +180,7 @@ typedef struct {
} proxy_status; /* Status display options */
char proxy_status_set;
apr_pool_t *pool; /* Pool used for allocating this struct */
apr_array_header_t *lbmethods;
} proxy_server_conf;
@@ -257,6 +259,7 @@ typedef struct {
apr_size_t elected; /* Number of times the worker was elected */
char route[PROXY_WORKER_MAX_ROUTE_SIZ+1];
char redirect[PROXY_WORKER_MAX_ROUTE_SIZ+1];
void *context; /* general purpose storage */
} proxy_worker_stat;
/* Worker configuration */
@@ -293,6 +296,7 @@ struct proxy_worker {
#if APR_HAS_THREADS
apr_thread_mutex_t *mutex; /* Thread lock for updating address cache */
#endif
void *context; /* general purpose storage */
};
struct proxy_balancer {
@@ -303,10 +307,7 @@ struct proxy_balancer {
apr_interval_time_t timeout; /* Timeout for waiting on free connection */
int max_attempts; /* Number of attempts before failing */
char max_attempts_set;
enum {
lbmethod_requests = 1,
lbmethod_traffic = 2
} lbmethod;
proxy_balancer_method *lbmethod;
/* XXX: Perhaps we will need the proc mutex too.
* Altrough we are only using arithmetic operations
@@ -316,6 +317,14 @@ struct proxy_balancer {
#if APR_HAS_THREADS
apr_thread_mutex_t *mutex; /* Thread lock for updating lb params */
#endif
void *context; /* general purpose storage */
};
struct proxy_balancer_method {
const char *name; /* name of the load balancer method*/
proxy_worker *(*finder)(proxy_balancer *balancer,
request_rec *r);
void *context; /* general purpose storage */
};
#if APR_HAS_THREADS
@@ -365,6 +374,14 @@ APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, canon_handler, (request_rec *r,
APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, create_req, (request_rec *r, request_rec *pr))
APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, fixups, (request_rec *r))
/*
* Useful hook run within the create per-server phase which
* adds the required lbmethod structs, so they exist at
* configure time
*/
APR_DECLARE_EXTERNAL_HOOK(proxy, PROXY, int, load_lbmethods,
(proxy_server_conf *conf))
/**
* pre request hook.
* It will return the most suitable worker at the moment

104
modules/proxy/mod_proxy_balancer.c
View File

@@ -21,6 +21,7 @@
#include "mod_proxy.h"
#include "ap_mpm.h"
#include "apr_version.h"
#include "apr_hooks.h"
module AP_MODULE_DECLARE_DATA proxy_balancer_module;
@@ -262,13 +263,14 @@ static proxy_worker *find_session_route(proxy_balancer *balancer,
* b a d c d a c d b d ...
*
*/
static proxy_worker *find_best_byrequests(proxy_balancer *balancer,
request_rec *r)
request_rec *r)
{
int i;
int total_factor = 0;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
proxy_worker *candidate = NULL;
proxy_worker *mycandidate = NULL;
/* First try to see if we have available candidate */
for (i = 0; i < balancer->workers->nelts; i++) {
@@ -286,18 +288,18 @@ static proxy_worker *find_best_byrequests(proxy_balancer *balancer,
if (PROXY_WORKER_IS_USABLE(worker)) {
worker->s->lbstatus += worker->s->lbfactor;
total_factor += worker->s->lbfactor;
if (!candidate || worker->s->lbstatus > candidate->s->lbstatus)
candidate = worker;
if (!mycandidate || worker->s->lbstatus > mycandidate->s->lbstatus)
mycandidate = worker;
}
worker++;
}
if (candidate) {
candidate->s->lbstatus -= total_factor;
candidate->s->elected++;
if (mycandidate) {
mycandidate->s->lbstatus -= total_factor;
mycandidate->s->elected++;
}
return candidate;
return mycandidate;
}
/*
@@ -318,13 +320,13 @@ static proxy_worker *find_best_byrequests(proxy_balancer *balancer,
* chosen more often, to even things out.
*/
static proxy_worker *find_best_bytraffic(proxy_balancer *balancer,
request_rec *r)
request_rec *r)
{
int i;
apr_off_t mytraffic = 0;
apr_off_t curmin = 0;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
proxy_worker *candidate = NULL;
proxy_worker *mycandidate = NULL;
/* First try to see if we have available candidate */
for (i = 0; i < balancer->workers->nelts; i++) {
@@ -342,19 +344,19 @@ static proxy_worker *find_best_bytraffic(proxy_balancer *balancer,
if (PROXY_WORKER_IS_USABLE(worker)) {
mytraffic = (worker->s->transferred/worker->s->lbfactor) +
(worker->s->read/worker->s->lbfactor);
if (!candidate || mytraffic < curmin) {
candidate = worker;
if (!mycandidate || mytraffic < curmin) {
mycandidate = worker;
curmin = mytraffic;
}
}
worker++;
}
if (candidate) {
candidate->s->elected++;
if (mycandidate) {
mycandidate->s->elected++;
}
return candidate;
return mycandidate;
}
static proxy_worker *find_best_worker(proxy_balancer *balancer,
@@ -365,14 +367,12 @@ static proxy_worker *find_best_worker(proxy_balancer *balancer,
if (PROXY_THREAD_LOCK(balancer) != APR_SUCCESS)
return NULL;
if (balancer->lbmethod == lbmethod_requests) {
candidate = find_best_byrequests(balancer, r);
} else if (balancer->lbmethod == lbmethod_traffic) {
candidate = find_best_bytraffic(balancer, r);
} else {
candidate = (*balancer->lbmethod->finder)(balancer, r);
/*
PROXY_THREAD_UNLOCK(balancer);
return NULL;
}
*/
PROXY_THREAD_UNLOCK(balancer);
@@ -657,18 +657,15 @@ static int balancer_handler(request_rec *r)
bsel->max_attempts_set = 1;
}
if ((val = apr_table_get(params, "lm"))) {
int ival = atoi(val);
switch(ival) {
case 0:
break;
case lbmethod_traffic:
bsel->lbmethod = lbmethod_traffic;
break;
case lbmethod_requests:
bsel->lbmethod = lbmethod_requests;
break;
default:
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++;
}
}
}
@@ -755,8 +752,7 @@ static int balancer_handler(request_rec *r)
apr_time_sec(balancer->timeout));
ap_rprintf(r, "<td>%d</td>\n", balancer->max_attempts);
ap_rprintf(r, "<td>%s</td>\n",
balancer->lbmethod == lbmethod_requests ? "Requests" :
balancer->lbmethod == lbmethod_traffic ? "Traffic" : "Unknown");
balancer->lbmethod->name);
ap_rputs("</table>\n", r);
ap_rputs("\n\n<table border=\"0\"><tr>"
"<th>Scheme</th><th>Host</th>"
@@ -834,10 +830,17 @@ static int balancer_handler(request_rec *r)
ap_rprintf(r, "value=\"%d\"></td></tr>\n",
bsel->max_attempts);
ap_rputs("<tr><td>LB Method:</td><td><select name=\"lm\">", r);
ap_rprintf(r, "<option value=\"%d\" %s>Requests</option>", lbmethod_requests,
bsel->lbmethod == lbmethod_requests ? "selected" : "");
ap_rprintf(r, "<option value=\"%d\" %s>Traffic</option>", lbmethod_traffic,
bsel->lbmethod == lbmethod_traffic ? "selected" : "");
{
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);
@@ -871,6 +874,30 @@ static void child_init(apr_pool_t *p, server_rec *s)
}
/*
* How to add additional lbmethods:
* 1. Create func which determines "best" candidate worker
* (eg: find_best_bytraffic, above)
* 2. Create proxy_balancer_method struct which
* defines the method and add it to
* available server methods using
* the proxy_hook_load_lbmethods hook
* (eg: add_lbmethods below).
*/
static int add_lbmethods(proxy_server_conf *conf)
{
proxy_balancer_method *new;
new = apr_array_push(conf->lbmethods);
new->name = "byrequests";
new->finder = find_best_byrequests;
new = apr_array_push(conf->lbmethods);
new->name = "bytraffic";
new->finder = find_best_bytraffic;
return OK;
}
static void ap_proxy_balancer_register_hook(apr_pool_t *p)
{
/* Only the mpm_winnt has child init hook handler.
@@ -884,6 +911,7 @@ static void ap_proxy_balancer_register_hook(apr_pool_t *p)
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);
proxy_hook_load_lbmethods(add_lbmethods, NULL, NULL, APR_HOOK_FIRST);
}
module AP_MODULE_DECLARE_DATA proxy_balancer_module = {

16
modules/proxy/proxy_util.c
View File

@@ -1155,6 +1155,8 @@ PROXY_DECLARE(const char *) ap_proxy_add_balancer(proxy_balancer **balancer,
const char *url)
{
char *c, *q, *uri = apr_pstrdup(p, url);
int i;
proxy_balancer_method *lbmethod;
c = strchr(uri, ':');
if (c == NULL || c[1] != '/' || c[2] != '/' || c[3] == '\0')
@@ -1167,8 +1169,20 @@ PROXY_DECLARE(const char *) ap_proxy_add_balancer(proxy_balancer **balancer,
*balancer = apr_array_push(conf->balancers);
memset(*balancer, 0, sizeof(proxy_balancer));
/*
* NOTE: The default method is byrequests, which we assume
* exists!
*/
lbmethod = (proxy_balancer_method *)conf->lbmethods->elts;
for (i = 0; i < conf->lbmethods->nelts; i++) {
if (!strcasecmp(lbmethod->name, "byrequests")) {
break;
}
lbmethod++;
}
(*balancer)->name = uri;
(*balancer)->lbmethod = lbmethod_requests;
(*balancer)->lbmethod = lbmethod;
(*balancer)->workers = apr_array_make(p, 5, sizeof(proxy_worker));
/* XXX Is this a right place to create mutex */
#if APR_HAS_THREADS