[nginx] HTTP/2: limited maximum number of requests in connection.

[Valentin Bartenev]

details:   http://hg.nginx.org/nginx/rev/9027991e2f37
branches:  
changeset: 6783:9027991e2f37
user:      Valentin Bartenev <vbart at nginx.com>
date:      Mon Oct 31 16:33:02 2016 +0300
description:
HTTP/2: limited maximum number of requests in connection.

The new directive "http2_max_requests" is introduced.  From users point of
view it works quite similar to "keepalive_requests" but has significantly
bigger default value that is more suitable for HTTP/2.

diffstat:

 src/http/v2/ngx_http_v2.c        |  34 ++++++++++++++++++++++++----------
 src/http/v2/ngx_http_v2_module.c |   9 +++++++++
 src/http/v2/ngx_http_v2_module.h |   1 +
 3 files changed, 34 insertions(+), 10 deletions(-)

diffs (95 lines):

diff -r b123eae3fd4e -r 9027991e2f37 src/http/v2/ngx_http_v2.c
--- a/src/http/v2/ngx_http_v2.c	Thu Oct 27 17:57:16 2016 +0300
+++ b/src/http/v2/ngx_http_v2.c	Mon Oct 31 16:33:02 2016 +0300
@@ -326,16 +326,21 @@ ngx_http_v2_read_handler(ngx_event_t *re
 
     if (c->close) {
         c->close = 0;
-        h2c->goaway = 1;
-
-        if (ngx_http_v2_send_goaway(h2c, NGX_HTTP_V2_NO_ERROR) == NGX_ERROR) {
-            ngx_http_v2_finalize_connection(h2c, 0);
-            return;
-        }
-
-        if (ngx_http_v2_send_output_queue(h2c) == NGX_ERROR) {
-            ngx_http_v2_finalize_connection(h2c, 0);
-            return;
+
+        if (!h2c->goaway) {
+            h2c->goaway = 1;
+
+            if (ngx_http_v2_send_goaway(h2c, NGX_HTTP_V2_NO_ERROR)
+                == NGX_ERROR)
+            {
+                ngx_http_v2_finalize_connection(h2c, 0);
+                return;
+            }
+
+            if (ngx_http_v2_send_output_queue(h2c) == NGX_ERROR) {
+                ngx_http_v2_finalize_connection(h2c, 0);
+                return;
+            }
         }
 
         h2c->blocked = 0;
@@ -1177,6 +1182,15 @@ ngx_http_v2_state_headers(ngx_http_v2_co
         ngx_http_v2_set_dependency(h2c, node, depend, excl);
     }
 
+    if (h2c->connection->requests >= h2scf->max_requests) {
+        h2c->goaway = 1;
+
+        if (ngx_http_v2_send_goaway(h2c, NGX_HTTP_V2_NO_ERROR) == NGX_ERROR) {
+            return ngx_http_v2_connection_error(h2c,
+                                                NGX_HTTP_V2_INTERNAL_ERROR);
+        }
+    }
+
     return ngx_http_v2_state_header_block(h2c, pos, end);
 
 rst_stream:
diff -r b123eae3fd4e -r 9027991e2f37 src/http/v2/ngx_http_v2_module.c
--- a/src/http/v2/ngx_http_v2_module.c	Thu Oct 27 17:57:16 2016 +0300
+++ b/src/http/v2/ngx_http_v2_module.c	Mon Oct 31 16:33:02 2016 +0300
@@ -73,6 +73,13 @@ static ngx_command_t  ngx_http_v2_comman
       offsetof(ngx_http_v2_srv_conf_t, concurrent_streams),
       NULL },
 
+    { ngx_string("http2_max_requests"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_SRV_CONF_OFFSET,
+      offsetof(ngx_http_v2_srv_conf_t, max_requests),
+      NULL },
+
     { ngx_string("http2_max_field_size"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_size_slot,
@@ -322,6 +329,7 @@ ngx_http_v2_create_srv_conf(ngx_conf_t *
     h2scf->pool_size = NGX_CONF_UNSET_SIZE;
 
     h2scf->concurrent_streams = NGX_CONF_UNSET_UINT;
+    h2scf->max_requests = NGX_CONF_UNSET_UINT;
 
     h2scf->max_field_size = NGX_CONF_UNSET_SIZE;
     h2scf->max_header_size = NGX_CONF_UNSET_SIZE;
@@ -347,6 +355,7 @@ ngx_http_v2_merge_srv_conf(ngx_conf_t *c
 
     ngx_conf_merge_uint_value(conf->concurrent_streams,
                               prev->concurrent_streams, 128);
+    ngx_conf_merge_uint_value(conf->max_requests, prev->max_requests, 1000);
 
     ngx_conf_merge_size_value(conf->max_field_size, prev->max_field_size,
                               4096);
diff -r b123eae3fd4e -r 9027991e2f37 src/http/v2/ngx_http_v2_module.h
--- a/src/http/v2/ngx_http_v2_module.h	Thu Oct 27 17:57:16 2016 +0300
+++ b/src/http/v2/ngx_http_v2_module.h	Mon Oct 31 16:33:02 2016 +0300
@@ -23,6 +23,7 @@ typedef struct {
 typedef struct {
     size_t                          pool_size;
     ngx_uint_t                      concurrent_streams;
+    ngx_uint_t                      max_requests;
     size_t                          max_field_size;
     size_t                          max_header_size;
     size_t                          preread_size;