Persist local balancer-manager changes across restart/graceful.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1387110 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -1,6 +1,10 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_proxy: Allow for persistence of local changes (via the
+     balancer-manager) between graceful and normal restarts.
+     [Jim Jagielski]
+
   *) mod_slotmem: New provider function, fgrab(), which forces an
      allocation of a slot. [Jim Jagielski]
 

docs/manual/mod/mod_proxy.xml

@@ -649,6 +649,26 @@ expressions</description>
 </usage>
 </directivesynopsis>
 
+<directivesynopsis>
+    <name>BalancerPersist</name>
+    <description>Attempt to persist changes made by the Balancer Manager across restarts.</description>
+    <syntax>BalancerPersist On|Off</syntax>
+    <default>BalancerPersist Off</default>
+    <contextlist><context>server config</context><context>virtual host</context></contextlist>
+    <compatibility>BalancerPersist is only available in Apache HTTP Server 2.5.0
+        and later.</compatibility>
+    <usage>
+        <p>This directive will cause the shared memory storage associated
+        with the balancers and balancer members to be persisted across
+        restarts. This allows these local changes to not be lost during the
+        normal restart/graceful state transitions.</p>
+    </usage>
+    <note type="warning"><title>Warning</title>
+        <p>Data is not persisted across a stop/start cycle.</p>
+    </note>
+</directivesynopsis>
+    
+
 <directivesynopsis>
     <name>BalancerMember</name>
     <description>Add a member to a load balancing group</description>

include/ap_mmn.h

@@ -400,6 +400,7 @@
  * 20120724.0 (2.5.0-dev)  Add hostname argument to ap_proxy_checkproxyblock.
  * 20120724.1 (2.5.0-dev)  Add post_perdir_config hook.
  * 20120724.2 (2.5.0-dev)  Add fgrab slotmem function to struct
+ * 20120724.3 (2.5.0-dev)  Add bal_persist to proxy_server_conf
  */
 
 #define MODULE_MAGIC_COOKIE 0x41503235UL /* "AP25" */
@@ -407,7 +408,7 @@
 #ifndef MODULE_MAGIC_NUMBER_MAJOR
 #define MODULE_MAGIC_NUMBER_MAJOR 20120724
 #endif
-#define MODULE_MAGIC_NUMBER_MINOR 2                   /* 0...n */
+#define MODULE_MAGIC_NUMBER_MINOR 3                   /* 0...n */
 
 /**
  * Determine if the server's current MODULE_MAGIC_NUMBER is at least a

modules/proxy/mod_proxy.c

@@ -1145,13 +1145,14 @@ static void * create_proxy_config(apr_pool_t *p, server_rec *s)
 #if 0
     id = ap_proxy_hashfunc(apr_psprintf(p, "%pp-%" APR_TIME_T_FMT, ps, apr_time_now()), PROXY_HASHFUNC_DEFAULT);
 #else
-    id = ap_proxy_hashfunc(apr_psprintf(p, "%pp", ps), PROXY_HASHFUNC_DEFAULT);
+    id = ap_proxy_hashfunc(apr_psprintf(p, "%pp", s), PROXY_HASHFUNC_DEFAULT);
 #endif
     ps->id = apr_psprintf(p, "s%x", id);
     ps->viaopt = via_off; /* initially backward compatible with 1.3.1 */
     ps->viaopt_set = 0; /* 0 means default */
     ps->req = 0;
     ps->max_balancers = 0;
+    ps->bal_persist = 0;
     ps->bgrowth = 5;
     ps->bgrowth_set = 0;
     ps->req_set = 0;
@@ -1197,6 +1198,7 @@ static void * merge_proxy_config(apr_pool_t *p, void *basev, void *overridesv)
     ps->bgrowth = (overrides->bgrowth_set == 0) ? base->bgrowth : overrides->bgrowth;
     ps->bgrowth_set = overrides->bgrowth_set || base->bgrowth_set;
     ps->max_balancers = overrides->max_balancers || base->max_balancers;
+    ps->bal_persist = overrides->bal_persist || base->bal_persist;
     ps->recv_buffer_size = (overrides->recv_buffer_size_set == 0) ? base->recv_buffer_size : overrides->recv_buffer_size;
     ps->recv_buffer_size_set = overrides->recv_buffer_size_set || base->recv_buffer_size_set;
     ps->io_buffer_size = (overrides->io_buffer_size_set == 0) ? base->io_buffer_size : overrides->io_buffer_size;
@@ -1872,6 +1874,15 @@ static const char *set_bgrowth(cmd_parms *parms, void *dummy, const char *arg)
     return NULL;
 }
 
+static const char *set_persist(cmd_parms *parms, void *dummy, int flag)
+{
+    proxy_server_conf *psf =
+    ap_get_module_config(parms->server->module_config, &proxy_module);
+
+    psf->bal_persist = flag;
+    return NULL;
+}
+
 static const char *add_member(cmd_parms *cmd, void *dummy, const char *arg)
 {
     server_rec *s = cmd->server;
@@ -2259,6 +2270,8 @@ static const command_rec proxy_cmds[] =
      "A balancer name and scheme with list of params"),
     AP_INIT_TAKE1("BalancerGrowth", set_bgrowth, NULL, RSRC_CONF,
      "Number of additional Balancers that can be added post-config"),
+    AP_INIT_FLAG("BalancerPersist", set_persist, NULL, RSRC_CONF,
+     "on if the balancer should persist changes on reboot/restart made via the Balancer Manager"),
     AP_INIT_TAKE1("ProxyStatus", set_status_opt, NULL, RSRC_CONF,
      "Configure Status: proxy status to one of: on | off | full"),
     AP_INIT_RAW_ARGS("ProxySet", set_proxy_param, NULL, RSRC_CONF|ACCESS_CONF,

modules/proxy/mod_proxy.h

@@ -178,6 +178,7 @@ typedef struct {
     unsigned int proxy_status_set:1;
     unsigned int source_address_set:1;
     unsigned int bgrowth_set:1;
+    unsigned int bal_persist:1;
 } proxy_server_conf;
 
 

modules/proxy/mod_proxy_balancer.c

@@ -744,6 +744,7 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
     while (s) {
         int i,j;
         proxy_balancer *balancer;
+        ap_slotmem_type_t type;
         sconf = s->module_config;
         conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
 
@@ -753,6 +754,11 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
             s = s->next;
             continue;
         }
+        if (conf->bal_persist) {
+            type = AP_SLOTMEM_TYPE_PREGRAB | AP_SLOTMEM_TYPE_PERSIST;
+        } else {
+            type = AP_SLOTMEM_TYPE_PREGRAB;
+        }
         if (conf->balancers->nelts) {
             conf->max_balancers = conf->balancers->nelts + conf->bgrowth;
             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01178) "Doing balancers create: %d, %d (%d)",
@@ -761,7 +767,7 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
 
             rv = storage->create(&new, conf->id,
                                  ALIGNED_PROXY_BALANCER_SHARED_SIZE,
-                                 conf->max_balancers, AP_SLOTMEM_TYPE_PREGRAB, pconf);
+                                 conf->max_balancers, type, pconf);
             if (rv != APR_SUCCESS) {
                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01179) "balancer slotmem_create failed");
                 return !OK;
@@ -776,7 +782,6 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
             proxy_worker **workers;
             proxy_worker *worker;
             proxy_balancer_shared *bshm;
-            unsigned int index;
 
             balancer->max_workers = balancer->workers->nelts + balancer->growth;
 
@@ -794,29 +799,29 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
                                       apr_pool_cleanup_null);
 
             /* setup shm for balancers */
-            if ((rv = storage->grab(conf->bslot, &index)) != APR_SUCCESS) {
+            if ((rv = storage->fgrab(conf->bslot, i)) != APR_SUCCESS) {
                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01181) "balancer slotmem_grab failed");
                 return !OK;
 
             }
-            if ((rv = storage->dptr(conf->bslot, index, (void *)&bshm)) != APR_SUCCESS) {
+            if ((rv = storage->dptr(conf->bslot, i, (void *)&bshm)) != APR_SUCCESS) {
                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01182) "balancer slotmem_dptr failed");
                 return !OK;
             }
-            if ((rv = ap_proxy_share_balancer(balancer, bshm, index)) != APR_SUCCESS) {
+            if ((rv = ap_proxy_share_balancer(balancer, bshm, i)) != APR_SUCCESS) {
                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01183) "Cannot share balancer");
                 return !OK;
             }
 
             /* create slotmem slots for workers */
-            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01184) "Doing workers create: %s (%s), %d, %d",
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01184) "Doing workers create: %s (%s), %d, %d [%u]",
                          balancer->s->name, balancer->s->sname,
                          (int)ALIGNED_PROXY_WORKER_SHARED_SIZE,
-                         (int)balancer->max_workers);
+                         (int)balancer->max_workers, i);
 
             rv = storage->create(&new, balancer->s->sname,
                                  ALIGNED_PROXY_WORKER_SHARED_SIZE,
-                                 balancer->max_workers, AP_SLOTMEM_TYPE_PREGRAB, pconf);
+                                 balancer->max_workers, type, pconf);
             if (rv != APR_SUCCESS) {
                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01185) "worker slotmem_create failed");
                 return !OK;
@@ -833,21 +838,26 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
                 proxy_worker_shared *shm;
 
                 worker = *workers;
-                if ((rv = storage->grab(balancer->wslot, &index)) != APR_SUCCESS) {
+                if ((rv = storage->fgrab(balancer->wslot, j)) != APR_SUCCESS) {
                     ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01186) "worker slotmem_grab failed");
                     return !OK;
 
                 }
-                if ((rv = storage->dptr(balancer->wslot, index, (void *)&shm)) != APR_SUCCESS) {
+                if ((rv = storage->dptr(balancer->wslot, j, (void *)&shm)) != APR_SUCCESS) {
                     ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01187) "worker slotmem_dptr failed");
                     return !OK;
                 }
-                if ((rv = ap_proxy_share_worker(worker, shm, index)) != APR_SUCCESS) {
+                if ((rv = ap_proxy_share_worker(worker, shm, j)) != APR_SUCCESS) {
                     ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01188) "Cannot share worker");
                     return !OK;
                 }
                 worker->s->updated = tstamp;
             }
+            if (conf->bal_persist) {
+                /* We could have just read-in a persisted config. Force a sync. */
+                balancer->wupdated--;
+                ap_proxy_sync_balancer(balancer, s, conf);
+            }
         }
         s = s->next;
     }

modules/proxy/proxy_util.c

@@ -1198,9 +1198,12 @@ PROXY_DECLARE(apr_status_t) ap_proxy_share_balancer(proxy_balancer *balancer,
     if (!shm || !balancer->s)
         return APR_EINVAL;
 
-    memcpy(shm, balancer->s, sizeof(proxy_balancer_shared));
+    if ((balancer->s->hash.def != shm->hash.def) ||
-    if (balancer->s->was_malloced)
+        (balancer->s->hash.fnv != shm->hash.fnv)) {
-        free(balancer->s);
+        memcpy(shm, balancer->s, sizeof(proxy_balancer_shared));
+        if (balancer->s->was_malloced)
+            free(balancer->s);
+    }
     balancer->s = shm;
     balancer->s->index = i;
     /* the below should always succeed */
@@ -1637,9 +1640,13 @@ PROXY_DECLARE(apr_status_t) ap_proxy_share_worker(proxy_worker *worker, proxy_wo
     if (!shm || !worker->s)
         return APR_EINVAL;
 
-    memcpy(shm, worker->s, sizeof(proxy_worker_shared));
+    if ((worker->s->hash.def != shm->hash.def) ||
-    if (worker->s->was_malloced)
+        (worker->s->hash.fnv != shm->hash.fnv)) {
-        free(worker->s); /* was malloced in ap_proxy_define_worker */
+        memcpy(shm, worker->s, sizeof(proxy_worker_shared));
+        if (worker->s->was_malloced)
+            free(worker->s); /* was malloced in ap_proxy_define_worker */
+    }
+
     worker->s = shm;
     worker->s->index = i;
     return APR_SUCCESS;