Upstream: limited next_upstream time and tries (ticket #544).

The new directives {proxy,fastcgi,scgi,uwsgi,memcached}_next_upstream_tries
and {proxy,fastcgi,scgi,uwsgi,memcached}_next_upstream_timeout limit
the number of upstreams tried and the maximum time spent for these tries
when searching for a valid upstream.
diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index 7be137a..9847ec1 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -442,6 +442,20 @@
       offsetof(ngx_http_fastcgi_loc_conf_t, upstream.next_upstream),
       &ngx_http_fastcgi_next_upstream_masks },
 
+    { ngx_string("fastcgi_next_upstream_tries"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_fastcgi_loc_conf_t, upstream.next_upstream_tries),
+      NULL },
+
+    { ngx_string("fastcgi_next_upstream_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_fastcgi_loc_conf_t, upstream.next_upstream_timeout),
+      NULL },
+
     { ngx_string("fastcgi_param"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE23,
       ngx_http_upstream_param_set_slot,
@@ -2314,6 +2328,7 @@
 
     conf->upstream.store = NGX_CONF_UNSET;
     conf->upstream.store_access = NGX_CONF_UNSET_UINT;
+    conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT;
     conf->upstream.buffering = NGX_CONF_UNSET;
     conf->upstream.ignore_client_abort = NGX_CONF_UNSET;
 
@@ -2322,6 +2337,7 @@
     conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
 
     conf->upstream.send_lowat = NGX_CONF_UNSET_SIZE;
     conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
@@ -2387,6 +2403,9 @@
     ngx_conf_merge_uint_value(conf->upstream.store_access,
                               prev->upstream.store_access, 0600);
 
+    ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries,
+                              prev->upstream.next_upstream_tries, 0);
+
     ngx_conf_merge_value(conf->upstream.buffering,
                               prev->upstream.buffering, 1);
 
@@ -2405,6 +2424,9 @@
     ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                               prev->upstream.read_timeout, 60000);
 
+    ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
+                              prev->upstream.next_upstream_timeout, 0);
+
     ngx_conf_merge_size_value(conf->upstream.send_lowat,
                               prev->upstream.send_lowat, 0);
 
diff --git a/src/http/modules/ngx_http_memcached_module.c b/src/http/modules/ngx_http_memcached_module.c
index 9636028..17f1d8e 100644
--- a/src/http/modules/ngx_http_memcached_module.c
+++ b/src/http/modules/ngx_http_memcached_module.c
@@ -102,6 +102,20 @@
       offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream),
       &ngx_http_memcached_next_upstream_masks },
 
+    { ngx_string("memcached_next_upstream_tries"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream_tries),
+      NULL },
+
+    { ngx_string("memcached_next_upstream_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream_timeout),
+      NULL },
+
     { ngx_string("memcached_gzip_flag"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_num_slot,
@@ -583,9 +597,11 @@
      */
 
     conf->upstream.local = NGX_CONF_UNSET_PTR;
+    conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT;
     conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
 
     conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
 
@@ -619,6 +635,9 @@
     ngx_conf_merge_ptr_value(conf->upstream.local,
                               prev->upstream.local, NULL);
 
+    ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries,
+                              prev->upstream.next_upstream_tries, 0);
+
     ngx_conf_merge_msec_value(conf->upstream.connect_timeout,
                               prev->upstream.connect_timeout, 60000);
 
@@ -628,6 +647,9 @@
     ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                               prev->upstream.read_timeout, 60000);
 
+    ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
+                              prev->upstream.next_upstream_timeout, 0);
+
     ngx_conf_merge_size_value(conf->upstream.buffer_size,
                               prev->upstream.buffer_size,
                               (size_t) ngx_pagesize);
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 52c63e1..c8a80ef 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -505,6 +505,20 @@
       offsetof(ngx_http_proxy_loc_conf_t, upstream.next_upstream),
       &ngx_http_proxy_next_upstream_masks },
 
+    { ngx_string("proxy_next_upstream_tries"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_proxy_loc_conf_t, upstream.next_upstream_tries),
+      NULL },
+
+    { ngx_string("proxy_next_upstream_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_proxy_loc_conf_t, upstream.next_upstream_timeout),
+      NULL },
+
     { ngx_string("proxy_pass_header"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_str_array_slot,
@@ -2455,6 +2469,7 @@
 
     conf->upstream.store = NGX_CONF_UNSET;
     conf->upstream.store_access = NGX_CONF_UNSET_UINT;
+    conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT;
     conf->upstream.buffering = NGX_CONF_UNSET;
     conf->upstream.ignore_client_abort = NGX_CONF_UNSET;
 
@@ -2463,6 +2478,7 @@
     conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
 
     conf->upstream.send_lowat = NGX_CONF_UNSET_SIZE;
     conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
@@ -2543,6 +2559,9 @@
     ngx_conf_merge_uint_value(conf->upstream.store_access,
                               prev->upstream.store_access, 0600);
 
+    ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries,
+                              prev->upstream.next_upstream_tries, 0);
+
     ngx_conf_merge_value(conf->upstream.buffering,
                               prev->upstream.buffering, 1);
 
@@ -2561,6 +2580,9 @@
     ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                               prev->upstream.read_timeout, 60000);
 
+    ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
+                              prev->upstream.next_upstream_timeout, 0);
+
     ngx_conf_merge_size_value(conf->upstream.send_lowat,
                               prev->upstream.send_lowat, 0);
 
diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
index b4b89ff..313f3b3 100644
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -299,6 +299,20 @@
       offsetof(ngx_http_scgi_loc_conf_t, upstream.next_upstream),
       &ngx_http_scgi_next_upstream_masks },
 
+    { ngx_string("scgi_next_upstream_tries"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_scgi_loc_conf_t, upstream.next_upstream_tries),
+      NULL },
+
+    { ngx_string("scgi_next_upstream_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_scgi_loc_conf_t, upstream.next_upstream_timeout),
+      NULL },
+
     { ngx_string("scgi_param"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE23,
       ngx_http_upstream_param_set_slot,
@@ -1074,6 +1088,7 @@
 
     conf->upstream.store = NGX_CONF_UNSET;
     conf->upstream.store_access = NGX_CONF_UNSET_UINT;
+    conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT;
     conf->upstream.buffering = NGX_CONF_UNSET;
     conf->upstream.ignore_client_abort = NGX_CONF_UNSET;
 
@@ -1082,6 +1097,7 @@
     conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
 
     conf->upstream.send_lowat = NGX_CONF_UNSET_SIZE;
     conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
@@ -1142,6 +1158,9 @@
     ngx_conf_merge_uint_value(conf->upstream.store_access,
                               prev->upstream.store_access, 0600);
 
+    ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries,
+                              prev->upstream.next_upstream_tries, 0);
+
     ngx_conf_merge_value(conf->upstream.buffering,
                               prev->upstream.buffering, 1);
 
@@ -1160,6 +1179,9 @@
     ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                               prev->upstream.read_timeout, 60000);
 
+    ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
+                              prev->upstream.next_upstream_timeout, 0);
+
     ngx_conf_merge_size_value(conf->upstream.send_lowat,
                               prev->upstream.send_lowat, 0);
 
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
index 0185cba..9556aa4 100644
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -354,6 +354,20 @@
       offsetof(ngx_http_uwsgi_loc_conf_t, upstream.next_upstream),
       &ngx_http_uwsgi_next_upstream_masks },
 
+    { ngx_string("uwsgi_next_upstream_tries"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_uwsgi_loc_conf_t, upstream.next_upstream_tries),
+      NULL },
+
+    { ngx_string("uwsgi_next_upstream_timeout"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_msec_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_uwsgi_loc_conf_t, upstream.next_upstream_timeout),
+      NULL },
+
     { ngx_string("uwsgi_param"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE23,
       ngx_http_upstream_param_set_slot,
@@ -1254,6 +1268,7 @@
 
     conf->upstream.store = NGX_CONF_UNSET;
     conf->upstream.store_access = NGX_CONF_UNSET_UINT;
+    conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT;
     conf->upstream.buffering = NGX_CONF_UNSET;
     conf->upstream.ignore_client_abort = NGX_CONF_UNSET;
 
@@ -1262,6 +1277,7 @@
     conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
     conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC;
 
     conf->upstream.send_lowat = NGX_CONF_UNSET_SIZE;
     conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;
@@ -1329,6 +1345,9 @@
     ngx_conf_merge_uint_value(conf->upstream.store_access,
                               prev->upstream.store_access, 0600);
 
+    ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries,
+                              prev->upstream.next_upstream_tries, 0);
+
     ngx_conf_merge_value(conf->upstream.buffering,
                               prev->upstream.buffering, 1);
 
@@ -1347,6 +1366,9 @@
     ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                               prev->upstream.read_timeout, 60000);
 
+    ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout,
+                              prev->upstream.next_upstream_timeout, 0);
+
     ngx_conf_merge_size_value(conf->upstream.send_lowat,
                               prev->upstream.send_lowat, 0);