# HG changeset patch
# User Igor Sysoev <igor@sysoev.ru>
# Date 1319472545 0
# Node ID 016352c19049192a1c2e6565e3e0c9b413ed2310
# Parent  4c4997de65b80604d60df31c13d2d51778302133
Support of several servers in the "resolver" directive.

Patch by Kirill A. Korinskiy.

diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c
--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -91,8 +91,10 @@ static u_char *ngx_resolver_log_error(ng
 
 
 ngx_resolver_t *
-ngx_resolver_create(ngx_conf_t *cf, ngx_addr_t *addr)
+ngx_resolver_create(ngx_conf_t *cf, ngx_str_t *names, ngx_uint_t n)
 {
+    ngx_url_t              u;
+    ngx_uint_t             i;
     ngx_resolver_t        *r;
     ngx_pool_cleanup_t    *cln;
     ngx_udp_connection_t  *uc;
@@ -109,6 +111,15 @@ ngx_resolver_create(ngx_conf_t *cf, ngx_
         return NULL;
     }
 
+    if (n) {
+        if (ngx_array_init(&r->udp_connections, cf->pool, n,
+                           sizeof(ngx_udp_connection_t))
+            != NGX_OK)
+        {
+            return NULL;
+        }
+    }
+
     cln->data = r;
 
     r->event = ngx_calloc(sizeof(ngx_event_t), cf->log);
@@ -140,17 +151,27 @@ ngx_resolver_create(ngx_conf_t *cf, ngx_
     r->log = &cf->cycle->new_log;
     r->log_level = NGX_LOG_ERR;
 
-    if (addr) {
-        uc = ngx_calloc(sizeof(ngx_udp_connection_t), cf->log);
+    for (i = 0; i < n; i++) {
+        ngx_memzero(&u, sizeof(ngx_url_t));
+
+        u.host = names[i];
+        u.port = 53;
+
+        if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V: %s", &u.host, u.err);
+            return NULL;
+        }
+
+        uc = ngx_array_push(&r->udp_connections);
         if (uc == NULL) {
             return NULL;
         }
 
-        r->udp_connection = uc;
-
-        uc->sockaddr = addr->sockaddr;
-        uc->socklen = addr->socklen;
-        uc->server = addr->name;
+        ngx_memzero(uc, sizeof(ngx_udp_connection_t));
+
+        uc->sockaddr = u.addrs->sockaddr;
+        uc->socklen = u.addrs->socklen;
+        uc->server = u.addrs->name;
 
         uc->log = cf->cycle->new_log;
         uc->log.handler = ngx_resolver_log_error;
@@ -167,6 +188,9 @@ ngx_resolver_cleanup(void *data)
 {
     ngx_resolver_t  *r = data;
 
+    ngx_uint_t             i;
+    ngx_udp_connection_t  *uc;
+
     if (r) {
         ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
                        "cleanup resolver");
@@ -179,12 +203,13 @@ ngx_resolver_cleanup(void *data)
             ngx_free(r->event);
         }
 
-        if (r->udp_connection) {
-            if (r->udp_connection->connection) {
-                ngx_close_connection(r->udp_connection->connection);
+
+        uc = r->udp_connections.elts;
+
+        for (i = 0; i < r->udp_connections.nelts; i++) {
+            if (uc[i].connection) {
+                ngx_close_connection(uc[i].connection);
             }
-
-            ngx_free(r->udp_connection);
         }
 
         ngx_free(r);
@@ -242,7 +267,7 @@ ngx_resolve_start(ngx_resolver_t *r, ngx
         }
     }
 
-    if (r->udp_connection == NULL) {
+    if (r->udp_connections.nelts == 0) {
         return NGX_NO_RESOLVER;
     }
 
@@ -826,7 +851,12 @@ ngx_resolver_send_query(ngx_resolver_t *
     ssize_t                n;
     ngx_udp_connection_t  *uc;
 
-    uc = r->udp_connection;
+    uc = r->udp_connections.elts;
+
+    uc = &uc[r->last_connection++];
+    if (r->last_connection == r->udp_connections.nelts) {
+        r->last_connection = 0;
+    }
 
     if (uc->connection == NULL) {
         if (ngx_udp_connect(uc) != NGX_OK) {
diff --git a/src/core/ngx_resolver.h b/src/core/ngx_resolver.h
--- a/src/core/ngx_resolver.h
+++ b/src/core/ngx_resolver.h
@@ -77,16 +77,16 @@ typedef struct {
 typedef struct {
     /* has to be pointer because of "incomplete type" */
     ngx_event_t              *event;
-
-    /* TODO: DNS peers balancer */
-    /* STUB */
-    ngx_udp_connection_t     *udp_connection;
-
+    void                     *dummy;
     ngx_log_t                *log;
 
     /* ident must be after 3 pointers */
     ngx_int_t                 ident;
 
+    /* simple round robin DNS peers balancer */
+    ngx_array_t               udp_connections;
+    ngx_uint_t                last_connection;
+
     ngx_rbtree_t              name_rbtree;
     ngx_rbtree_node_t         name_sentinel;
 
@@ -123,8 +123,6 @@ struct ngx_resolver_ctx_s {
     in_addr_t                *addrs;
     in_addr_t                 addr;
 
-    /* TODO: DNS peers balancer ctx */
-
     ngx_resolver_handler_pt   handler;
     void                     *data;
     ngx_msec_t                timeout;
@@ -135,7 +133,8 @@ struct ngx_resolver_ctx_s {
 };
 
 
-ngx_resolver_t *ngx_resolver_create(ngx_conf_t *cf, ngx_addr_t *addr);
+ngx_resolver_t *ngx_resolver_create(ngx_conf_t *cf, ngx_str_t *names,
+    ngx_uint_t n);
 ngx_resolver_ctx_t *ngx_resolve_start(ngx_resolver_t *r,
     ngx_resolver_ctx_t *temp);
 ngx_int_t ngx_resolve_name(ngx_resolver_ctx_t *ctx);
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -718,7 +718,7 @@ static ngx_command_t  ngx_http_core_comm
       NULL },
 
     { ngx_string("resolver"),
-      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
       ngx_http_core_resolver,
       NGX_HTTP_LOC_CONF_OFFSET,
       0,
@@ -3535,7 +3535,7 @@ ngx_http_core_merge_loc_conf(ngx_conf_t 
              * to inherit it in all servers
              */
 
-            prev->resolver = ngx_resolver_create(cf, NULL);
+            prev->resolver = ngx_resolver_create(cf, NULL, 0);
             if (prev->resolver == NULL) {
                 return NGX_CONF_ERROR;
             }
@@ -4540,7 +4540,6 @@ ngx_http_core_resolver(ngx_conf_t *cf, n
 {
     ngx_http_core_loc_conf_t  *clcf = conf;
 
-    ngx_url_t   u;
     ngx_str_t  *value;
 
     if (clcf->resolver) {
@@ -4549,21 +4548,11 @@ ngx_http_core_resolver(ngx_conf_t *cf, n
 
     value = cf->args->elts;
 
-    ngx_memzero(&u, sizeof(ngx_url_t));
-
-    u.host = value[1];
-    u.port = 53;
-
-    if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
-        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V: %s", &u.host, u.err);
+    clcf->resolver = ngx_resolver_create(cf, &value[1], cf->args->nelts - 1);
+    if (clcf->resolver == NULL) {
         return NGX_CONF_ERROR;
     }
 
-    clcf->resolver = ngx_resolver_create(cf, &u.addrs[0]);
-    if (clcf->resolver == NULL) {
-        return NGX_OK;
-    }
-
     return NGX_CONF_OK;
 }
 
diff --git a/src/mail/ngx_mail_core_module.c b/src/mail/ngx_mail_core_module.c
--- a/src/mail/ngx_mail_core_module.c
+++ b/src/mail/ngx_mail_core_module.c
@@ -69,7 +69,7 @@ static ngx_command_t  ngx_mail_core_comm
       NULL },
 
     { ngx_string("resolver"),
-      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
       ngx_mail_core_resolver,
       NGX_MAIL_SRV_CONF_OFFSET,
       0,
@@ -493,7 +493,6 @@ ngx_mail_core_resolver(ngx_conf_t *cf, n
 {
     ngx_mail_core_srv_conf_t  *cscf = conf;
 
-    ngx_url_t   u;
     ngx_str_t  *value;
 
     value = cf->args->elts;
@@ -507,21 +506,11 @@ ngx_mail_core_resolver(ngx_conf_t *cf, n
         return NGX_CONF_OK;
     }
 
-    ngx_memzero(&u, sizeof(ngx_url_t));
-
-    u.host = value[1];
-    u.port = 53;
-
-    if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
-        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V: %s", &u.host, u.err);
+    cscf->resolver = ngx_resolver_create(cf, &value[1], cf->args->nelts - 1);
+    if (cscf->resolver == NULL) {
         return NGX_CONF_ERROR;
     }
 
-    cscf->resolver = ngx_resolver_create(cf, &u.addrs[0]);
-    if (cscf->resolver == NULL) {
-        return NGX_CONF_OK;
-    }
-
     return NGX_CONF_OK;
 }