Cache: proxy_cache_lock_age and friends.

Once this age is reached, the cache lock is discarded and another
request can acquire the lock.  Requests which failed to acquire
the lock are not allowed to cache the response.

8 files changed, 71 insertions, 9 deletions

diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index b7f7ea14a..75fd20d34 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -419,6 +419,13 @@ static ngx_command_t  ngx_http_fastcgi_commands[] = {
       offsetof(ngx_http_fastcgi_loc_conf_t, upstream.cache_lock_timeout),
       NULL },
 
+    { ngx_string("fastcgi_cache_lock_age"),
+      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.cache_lock_age),
+      NULL },
+
     { ngx_string("fastcgi_cache_revalidate"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
       ngx_conf_set_flag_slot,
@@ -2374,6 +2381,7 @@ ngx_http_fastcgi_create_loc_conf(ngx_conf_t *cf)
     conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
     conf->upstream.cache_lock = NGX_CONF_UNSET;
     conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.cache_lock_age = NGX_CONF_UNSET_MSEC;
     conf->upstream.cache_revalidate = NGX_CONF_UNSET;
 #endif
 
@@ -2638,6 +2646,9 @@ ngx_http_fastcgi_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
                               prev->upstream.cache_lock_timeout, 5000);
 
+    ngx_conf_merge_msec_value(conf->upstream.cache_lock_age,
+                              prev->upstream.cache_lock_age, 5000);
+
     ngx_conf_merge_value(conf->upstream.cache_revalidate,
                               prev->upstream.cache_revalidate, 0);
 
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index f43bbc8c7..da4f7b2c7 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -489,6 +489,13 @@ static ngx_command_t  ngx_http_proxy_commands[] = {
       offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_lock_timeout),
       NULL },
 
+    { ngx_string("proxy_cache_lock_age"),
+      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.cache_lock_age),
+      NULL },
+
     { ngx_string("proxy_cache_revalidate"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
       ngx_conf_set_flag_slot,
@@ -2544,6 +2551,7 @@ ngx_http_proxy_create_loc_conf(ngx_conf_t *cf)
     conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
     conf->upstream.cache_lock = NGX_CONF_UNSET;
     conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.cache_lock_age = NGX_CONF_UNSET_MSEC;
     conf->upstream.cache_revalidate = NGX_CONF_UNSET;
 #endif
 
@@ -2818,6 +2826,9 @@ ngx_http_proxy_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
                               prev->upstream.cache_lock_timeout, 5000);
 
+    ngx_conf_merge_msec_value(conf->upstream.cache_lock_age,
+                              prev->upstream.cache_lock_age, 5000);
+
     ngx_conf_merge_value(conf->upstream.cache_revalidate,
                               prev->upstream.cache_revalidate, 0);
 
diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
index 71dcd34f9..ccbfd3263 100644
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -276,6 +276,13 @@ static ngx_command_t ngx_http_scgi_commands[] = {
       offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_lock_timeout),
       NULL },
 
+    { ngx_string("scgi_cache_lock_age"),
+      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.cache_lock_age),
+      NULL },
+
     { ngx_string("scgi_cache_revalidate"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
       ngx_conf_set_flag_slot,
@@ -1133,6 +1140,7 @@ ngx_http_scgi_create_loc_conf(ngx_conf_t *cf)
     conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
     conf->upstream.cache_lock = NGX_CONF_UNSET;
     conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.cache_lock_age = NGX_CONF_UNSET_MSEC;
     conf->upstream.cache_revalidate = NGX_CONF_UNSET;
 #endif
 
@@ -1392,6 +1400,9 @@ ngx_http_scgi_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
                               prev->upstream.cache_lock_timeout, 5000);
 
+    ngx_conf_merge_msec_value(conf->upstream.cache_lock_age,
+                              prev->upstream.cache_lock_age, 5000);
+
     ngx_conf_merge_value(conf->upstream.cache_revalidate,
                               prev->upstream.cache_revalidate, 0);
 
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
index eca145e1f..2a95faaea 100644
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -336,6 +336,13 @@ static ngx_command_t ngx_http_uwsgi_commands[] = {
       offsetof(ngx_http_uwsgi_loc_conf_t, upstream.cache_lock_timeout),
       NULL },
 
+    { ngx_string("uwsgi_cache_lock_age"),
+      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.cache_lock_age),
+      NULL },
+
     { ngx_string("uwsgi_cache_revalidate"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
       ngx_conf_set_flag_slot,
@@ -1339,6 +1346,7 @@ ngx_http_uwsgi_create_loc_conf(ngx_conf_t *cf)
     conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
     conf->upstream.cache_lock = NGX_CONF_UNSET;
     conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+    conf->upstream.cache_lock_age = NGX_CONF_UNSET_MSEC;
     conf->upstream.cache_revalidate = NGX_CONF_UNSET;
 #endif
 
@@ -1606,6 +1614,9 @@ ngx_http_uwsgi_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
                               prev->upstream.cache_lock_timeout, 5000);
 
+    ngx_conf_merge_msec_value(conf->upstream.cache_lock_age,
+                              prev->upstream.cache_lock_age, 5000);
+
     ngx_conf_merge_value(conf->upstream.cache_revalidate,
                               prev->upstream.cache_revalidate, 0);
 
diff --git a/src/http/ngx_http_cache.h b/src/http/ngx_http_cache.h
index f89766d58..033882e53 100644
--- a/src/http/ngx_http_cache.h
+++ b/src/http/ngx_http_cache.h
@@ -57,6 +57,7 @@ typedef struct {
     time_t                           valid_sec;
     size_t                           body_start;
     off_t                            fs_size;
+    ngx_msec_t                       lock_time;
 } ngx_http_file_cache_node_t;
 
 
@@ -91,6 +92,8 @@ struct ngx_http_cache_s {
     ngx_http_file_cache_node_t      *node;
 
     ngx_msec_t                       lock_timeout;
+    ngx_msec_t                       lock_age;
+    ngx_msec_t                       lock_time;
     ngx_msec_t                       wait_time;
 
     ngx_event_t                      wait_event;
diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index e7072e10e..043bf5ed5 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -396,13 +396,19 @@ ngx_http_file_cache_lock(ngx_http_request_t *r, ngx_http_cache_t *c)
         return NGX_DECLINED;
     }
 
+    now = ngx_current_msec;
+
     cache = c->file_cache;
 
     ngx_shmtx_lock(&cache->shpool->mutex);
 
-    if (!c->node->updating) {
+    timer = c->node->lock_time - now;
+
+    if (!c->node->updating || (ngx_msec_int_t) timer <= 0) {
         c->node->updating = 1;
+        c->node->lock_time = now + c->lock_age;
         c->updating = 1;
+        c->lock_time = c->node->lock_time;
     }
 
     ngx_shmtx_unlock(&cache->shpool->mutex);
@@ -415,9 +421,11 @@ ngx_http_file_cache_lock(ngx_http_request_t *r, ngx_http_cache_t *c)
         return NGX_DECLINED;
     }
 
-    c->waiting = 1;
+    if (c->lock_timeout == 0) {
+        return NGX_HTTP_CACHE_SCARCE;
+    }
 
-    now = ngx_current_msec;
+    c->waiting = 1;
 
     if (c->wait_time == 0) {
         c->wait_time = now + c->lock_timeout;
@@ -441,7 +449,7 @@ static void
 ngx_http_file_cache_lock_wait_handler(ngx_event_t *ev)
 {
     ngx_uint_t                 wait;
-    ngx_msec_t                 timer;
+    ngx_msec_t                 now, timer;
     ngx_http_cache_t          *c;
     ngx_http_request_t        *r;
     ngx_http_file_cache_t     *cache;
@@ -449,15 +457,17 @@ ngx_http_file_cache_lock_wait_handler(ngx_event_t *ev)
     r = ev->data;
     c = r->cache;
 
+    now = ngx_current_msec;
+
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, ev->log, 0,
                    "http file cache wait handler wt:%M cur:%M",
-                   c->wait_time, ngx_current_msec);
+                   c->wait_time, now);
 
-    timer = c->wait_time - ngx_current_msec;
+    timer = c->wait_time - now;
 
     if ((ngx_msec_int_t) timer <= 0) {
         ngx_log_error(NGX_LOG_INFO, ev->log, 0, "cache lock timeout");
-        c->lock = 0;
+        c->lock_timeout = 0;
         goto wakeup;
     }
 
@@ -466,7 +476,9 @@ ngx_http_file_cache_lock_wait_handler(ngx_event_t *ev)
 
     ngx_shmtx_lock(&cache->shpool->mutex);
 
-    if (c->node->updating) {
+    timer = c->node->lock_time - now;
+
+    if (c->node->updating && (ngx_msec_int_t) timer > 0) {
         wait = 1;
     }
 
@@ -588,6 +600,7 @@ ngx_http_file_cache_read(ngx_http_request_t *r, ngx_http_cache_t *c)
         } else {
             c->node->updating = 1;
             c->updating = 1;
+            c->lock_time = c->node->lock_time;
             rc = NGX_HTTP_CACHE_STALE;
         }
 
@@ -1453,7 +1466,7 @@ ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf)
     fcn = c->node;
     fcn->count--;
 
-    if (c->updating) {
+    if (c->updating && fcn->lock_time == c->lock_time) {
         fcn->updating = 0;
     }
 
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index f343d0463..d3e82829a 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -784,6 +784,7 @@ ngx_http_upstream_cache(ngx_http_request_t *r, ngx_http_upstream_t *u)
 
         c->lock = u->conf->cache_lock;
         c->lock_timeout = u->conf->cache_lock_timeout;
+        c->lock_age = u->conf->cache_lock_age;
 
         u->cache_status = NGX_HTTP_CACHE_MISS;
     }
diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index 0032c2c22..d04b66906 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -183,6 +183,7 @@ typedef struct {
 
     ngx_flag_t                       cache_lock;
     ngx_msec_t                       cache_lock_timeout;
+    ngx_msec_t                       cache_lock_age;
 
     ngx_flag_t                       cache_revalidate;