Introduce vhost_traffic_status_stats_by_upstream (#293)

Add new boolean flag `vhost_traffic_status_stats_by_upstream` to allow disabling statistics collection for upstream servers


---------

Co-authored-by: Ben Kochie <superq@gmail.com>

Author: u5surf

README.md

@@ -73,6 +73,7 @@ Table of Contents
   * [vhost_traffic_status_histogram_buckets](#vhost_traffic_status_histogram_buckets)
   * [vhost_traffic_status_bypass_limit](#vhost_traffic_status_bypass_limit)
   * [vhost_traffic_status_bypass_stats](#vhost_traffic_status_bypass_stats)
+  * [vhost_traffic_status_stats_by_upstream](#vhost_traffic_status_stats_by_upstream)
 * [Releases](#releases)
 * [See Also](#see-also)
 * [TODO](#todo)
@@ -1845,6 +1846,46 @@ http {
 }
 ```
 
+### vhost_traffic_status_stats_by_upstream
+
+| -   | - |
+| --- | --- |
+| **Syntax**  | **vhost_traffic_status_stats_by_upstream** \<on\|off\> |
+| **Default** | on  |
+| **Context** | http|
+
+`Description:` Enables or disables to stats `upstreamZone`.
+The `upstreamZone` in the traffic status stats features is bypassed if this option is disabled.
+In other words, it is excluded from the traffic status stats.
+This is mostly useful if you want to be disable statistics collection for upstream servers to reduce CPU load.
+
+```Nginx
+http {
+    vhost_traffic_status_zone;
+    vhost_traffic_status_stats_by_upstream off;
+
+    proxy_cache_path /var/cache/nginx keys_zone=zone1:1m max_size=1g inactive=24h;
+    upstream backend {
+       ...
+    }
+    ...
+
+    server {
+
+        ...
+
+        location /status {
+            vhost_traffic_status_display;
+            vhost_traffic_status_display_format html;
+        }
+        location /backend {
+            proxy_cache zone1;
+            proxy_pass http://backend;
+        }
+    }
+}
+```
+
 ## Releases
 
 To cut a release, create a changelog entry PR with [git-chglog](https://github.com/git-chglog/git-chglog)

src/ngx_http_vhost_traffic_status_display_json.c

@@ -837,7 +837,9 @@ ngx_http_vhost_traffic_status_display_set(ngx_http_request_t *r,
 
     buf--;
     buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_E);
-    buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_NEXT);
+    if (vtscf->stats_by_upstream) {
+        buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_NEXT);
+    }
 
     /* filterZones */
     o = buf;
@@ -854,25 +856,29 @@ ngx_http_vhost_traffic_status_display_set(ngx_http_request_t *r,
     } else {
         buf--;
         buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_E);
-        buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_NEXT);
+        if (vtscf->stats_by_upstream) {
+            buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_NEXT);
+        }
     }
 
     /* upstreamZones */
-    o = buf;
+    if (vtscf->stats_by_upstream) {
+        o = buf;
 
-    buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_UPSTREAM_S);
+        buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_UPSTREAM_S);
 
-    s = buf;
+        s = buf;
 
-    buf = ngx_http_vhost_traffic_status_display_set_upstream_group(r, buf);
+        buf = ngx_http_vhost_traffic_status_display_set_upstream_group(r, buf);
 
-    if (s == buf) {
-        buf = o;
-        buf--;
+        if (s == buf) {
+            buf = o;
+            buf--;
 
-    } else {
-        buf--;
-        buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_E);
+        } else {
+            buf--;
+            buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_JSON_FMT_E);
+        }
     }
 
 #if (NGX_HTTP_CACHE)

src/ngx_http_vhost_traffic_status_display_prometheus.c

@@ -527,16 +527,18 @@ ngx_http_vhost_traffic_status_display_prometheus_set(ngx_http_request_t *r,
     }
 
     /* upstreamZones */
-    o = buf;
+    if (vtscf->stats_by_upstream) {
+        o = buf;
 
-    buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_PROMETHEUS_FMT_UPSTREAM_S);
+        buf = ngx_sprintf(buf, NGX_HTTP_VHOST_TRAFFIC_STATUS_PROMETHEUS_FMT_UPSTREAM_S);
 
-    s = buf;
+        s = buf;
 
-    buf = ngx_http_vhost_traffic_status_display_prometheus_set_upstream(r, buf, node);
+        buf = ngx_http_vhost_traffic_status_display_prometheus_set_upstream(r, buf, node);
 
-    if (s == buf) {
-        buf = o;
+        if (s == buf) {
+            buf = o;
+        }
     }
 
 #if (NGX_HTTP_CACHE)

src/ngx_http_vhost_traffic_status_module.c

@@ -210,6 +210,13 @@ static ngx_command_t ngx_http_vhost_traffic_status_commands[] = {
       offsetof(ngx_http_vhost_traffic_status_loc_conf_t, bypass_stats),
       NULL },
 
+    { ngx_string("vhost_traffic_status_stats_by_upstream"),
+      NGX_HTTP_MAIN_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_vhost_traffic_status_loc_conf_t, stats_by_upstream),
+      NULL },
+
     ngx_null_command
 };
 
@@ -271,10 +278,12 @@ ngx_http_vhost_traffic_status_handler(ngx_http_request_t *r)
                       "handler::shm_add_server() failed");
     }
 
-    rc = ngx_http_vhost_traffic_status_shm_add_upstream(r);
-    if (rc != NGX_OK) {
-        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                      "handler::shm_add_upstream() failed");
+    if (vtscf->stats_by_upstream) {
+        rc = ngx_http_vhost_traffic_status_shm_add_upstream(r);
+        if (rc != NGX_OK) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "handler::shm_add_upstream() failed");
+        }
     }
 
     rc = ngx_http_vhost_traffic_status_shm_add_filter(r);
@@ -889,6 +898,7 @@ ngx_http_vhost_traffic_status_create_loc_conf(ngx_conf_t *cf)
      *     conf->histogram_buckets = { NULL, ... };
      *     conf->bypass_limit = 0;
      *     conf->bypass_stats = 0;
+     *     conf->stats_by_upstream = 0;
      */
 
     conf->shm_zone = NGX_CONF_UNSET_PTR;
@@ -908,6 +918,7 @@ ngx_http_vhost_traffic_status_create_loc_conf(ngx_conf_t *cf)
     conf->histogram_buckets = NGX_CONF_UNSET_PTR;
     conf->bypass_limit = NGX_CONF_UNSET;
     conf->bypass_stats = NGX_CONF_UNSET;
+    conf->stats_by_upstream = NGX_CONF_UNSET;
 
     conf->node_caches = ngx_pcalloc(cf->pool, sizeof(ngx_rbtree_node_t *)
                                     * (NGX_HTTP_VHOST_TRAFFIC_STATUS_UPSTREAM_FG + 1));
@@ -1019,6 +1030,8 @@ ngx_http_vhost_traffic_status_merge_loc_conf(ngx_conf_t *cf, void *parent, void
     ngx_conf_merge_value(conf->bypass_limit, prev->bypass_limit, 0);
     ngx_conf_merge_value(conf->bypass_stats, prev->bypass_stats, 0);
 
+    ngx_conf_merge_value(conf->stats_by_upstream, prev->stats_by_upstream, 1);
+
     name = ctx->shm_name;
 
     shm_zone = ngx_shared_memory_add(cf, &name, 0,

src/ngx_http_vhost_traffic_status_module.h

@@ -297,6 +297,8 @@ typedef struct {
     ngx_flag_t                              bypass_limit;
     ngx_flag_t                              bypass_stats;
 
+    ngx_flag_t                              stats_by_upstream;
+
     ngx_rbtree_node_t                     **node_caches;
 } ngx_http_vhost_traffic_status_loc_conf_t;