a.patch

gistfile1.txt

--- src/http/ngx_http_upstream_round_robin.c.orig	2011-09-30 14:30:01.000000000 +0000
+++ src/http/ngx_http_upstream_round_robin.c	2012-01-18 18:38:25.438381169 +0000
@@ -7,13 +7,44 @@
 #include <ngx_config.h>
 #include <ngx_core.h>
 #include <ngx_http.h>
+#include <ngx_supervisord.h>
+
+#if (NGX_SUPERVISORD_API_VERSION != 2)
+  #error "ngx_supervisord-aware upstream requires NGX_SUPERVISORD_API v2"
+#endif
 
 
+/*
+ * disable sorting
 static ngx_int_t ngx_http_upstream_cmp_servers(const void *one,
     const void *two);
+ */
 static ngx_uint_t
 ngx_http_upstream_get_peer(ngx_http_upstream_rr_peers_t *peers);
 
+void ngx_http_upstream_backend_monitor(ngx_http_upstream_srv_conf_t *uscf,
+    ngx_uint_t backend, ngx_uint_t new_status)
+{
+    ngx_http_upstream_rr_peers_t  *peers;
+    ngx_uint_t                     i;
+
+    peers = uscf->peer.data;
+    for (i = 0; i < peers->number; i++) {
+        if (peers->peer[i].onumber == backend) {
+            if (new_status == NGX_SUPERVISORD_SRV_UP) {
+                peers->peer[i].down = 0;
+                peers->peer[i].weight = peers->peer[i].oweight;
+                peers->peer[i].current_weight = peers->peer[i].oweight;
+            } else {
+               peers->peer[i].down = 1;
+                peers->peer[i].weight = 0;
+                peers->peer[i].current_weight = 0;
+            }
+        }
+    }
+}
+
+
 #if (NGX_HTTP_SSL)
 
 static ngx_int_t ngx_http_upstream_empty_set_session(ngx_peer_connection_t *pc,
@@ -23,7 +54,6 @@
 
 #endif
 
-
 ngx_int_t
 ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
     ngx_http_upstream_srv_conf_t *us)
@@ -36,6 +66,9 @@
     us->peer.init = ngx_http_upstream_init_round_robin_peer;
 
     if (us->servers) {
+        ngx_supervisord_add_backend_monitor(us,
+            ngx_http_upstream_backend_monitor);
+
         server = us->servers->elts;
 
         n = 0;
@@ -74,15 +107,20 @@
                 peers->peer[n].down = server[i].down;
                 peers->peer[n].weight = server[i].down ? 0 : server[i].weight;
                 peers->peer[n].current_weight = peers->peer[n].weight;
+                peers->peer[n].onumber = i;
+                peers->peer[n].oweight = server[i].weight;
                 n++;
             }
         }
 
         us->peer.data = peers;
 
+/*
+ * disable sorting
         ngx_sort(&peers->peer[0], (size_t) n,
                  sizeof(ngx_http_upstream_rr_peer_t),
                  ngx_http_upstream_cmp_servers);
+ */
 
         /* backup servers */
 
@@ -127,15 +165,20 @@
                 backup->peer[n].max_fails = server[i].max_fails;
                 backup->peer[n].fail_timeout = server[i].fail_timeout;
                 backup->peer[n].down = server[i].down;
+                backup->peer[n].onumber = i;
+                backup->peer[n].oweight = server[i].weight;
                 n++;
             }
         }
 
         peers->next = backup;
 
+/*
+ * disable sorting
         ngx_sort(&backup->peer[0], (size_t) n,
                  sizeof(ngx_http_upstream_rr_peer_t),
                  ngx_http_upstream_cmp_servers);
+ */
 
         return NGX_OK;
     }
@@ -185,6 +228,8 @@
         peers->peer[i].current_weight = 1;
         peers->peer[i].max_fails = 1;
         peers->peer[i].fail_timeout = 10;
+        peers->peer[i].onumber = 0;
+        peers->peer[i].oweight = 1;
     }
 
     us->peer.data = peers;
@@ -194,7 +239,8 @@
     return NGX_OK;
 }
 
-
+/*
+ * disable sorting
 static ngx_int_t
 ngx_http_upstream_cmp_servers(const void *one, const void *two)
 {
@@ -205,6 +251,7 @@
 
     return (first->weight < second->weight);
 }
+ */
 
 
 ngx_int_t
@@ -225,6 +272,7 @@
         r->upstream->peer.data = rrp;
     }
 
+    rrp->uscf = us;
     rrp->peers = us->peer.data;
     rrp->current = 0;
 
@@ -257,7 +305,7 @@
                                ngx_http_upstream_save_round_robin_peer_session;
 #endif
 
-    return NGX_OK;
+    return ngx_supervisord_check_servers(r);
 }
 
 
@@ -415,6 +463,16 @@
 
         /* there are several peers */
 
+        for (i = 0; i < rrp->peers->number; i++) {
+             if (!rrp->peers->peer[i].down) {
+                 break;
+             }
+        }
+
+        if (i == rrp->peers->number) {
+             goto failed;
+        }
+
         if (pc->tries == rrp->peers->number) {
 
             /* it's a first try - get a current peer */
@@ -685,6 +743,10 @@
             peer->current_weight = 0;
         }
 
+        peer->fails = 0;
+        (void) ngx_supervisord_execute(rrp->uscf, NGX_SUPERVISORD_CMD_STOP,
+                                       peer->onumber, NULL);
+
         /* ngx_unlock_mutex(rrp->peers->mutex); */
     }
 
--- src/http/ngx_http_upstream_round_robin.h.orig	2012-01-18 18:23:10.664996742 +0000
+++ src/http/ngx_http_upstream_round_robin.h	2012-01-18 18:41:18.750456106 +0000
@@ -17,9 +17,11 @@
     struct sockaddr                *sockaddr;
     socklen_t                       socklen;
     ngx_str_t                       name;
+    ngx_uint_t                      onumber;
 
     ngx_int_t                       current_weight;
     ngx_int_t                       weight;
+    ngx_int_t                       oweight;
 
     ngx_uint_t                      fails;
     time_t                          accessed;
@@ -54,6 +56,7 @@
 
 
 typedef struct {
+    ngx_http_upstream_srv_conf_t   *uscf;
     ngx_http_upstream_rr_peers_t   *peers;
     ngx_uint_t                      current;
     uintptr_t                      *tried;