feat(conf) configurable request body handling

Add directives for client_max_body_size and client_body_buffer_size,
allowing users to work around request body read limitations without
the need to use a custom Nginx config.

kong.conf.default

@@ -185,6 +185,36 @@
                                   # `text/html`, `application/json`, and
                                   # `application/xml`.
 
+#client_max_body_size = 0        # Defines the maximum request body size allowed
+                                 # by requests proxied by Kong, specified in the
+                                 # Content-Length request header. If a request
+                                 # exceeds this limit, Kong will respond with a
+                                 # 413 (Request Entity Too Large). Setting this
+                                 # value to 0 disables checking the request body
+                                 # size.
+# Note: See
+# http://nginx.org/en/docs/http/ngx_http_core_module.html#client_max_body_size
+# for further description of this parameter. Numeric values may be suffixed with
+# 'k' or 'm' to denote limits in terms of kilobytes or megabytes.
+
+#client_body_buffer_size = 8k    # Defines the buffer size for reading the
+                                 # request body. If the client request body is
+                                 # larger than this value, the body will be
+                                 # buffered to disk. Note that when the body is
+                                 # buffered to disk Kong plugins that access or
+                                 # manipulate the request body may not work, so
+                                 # it is advisable to set this value as high as
+                                 # possible (e.g., set it as high as
+                                 # `client_max_body_size` to force request
+                                 # bodies to be kept in memory). Do note that
+                                 # high-concurrency environments will require
+                                 # significant memory allocations to process
+                                 # many concurrent large request bodies.
+# Note: See
+# http://nginx.org/en/docs/http/ngx_http_core_module.html#client_body_buffer_size
+# for further description of this parameter. Numeric values may be suffixed with
+# 'k' or 'm' to denote limits in terms of kilobytes or megabytes.
+
 #------------------------------------------------------------------------------
 # DATASTORE
 #------------------------------------------------------------------------------

kong/conf_loader.lua

@@ -70,6 +70,9 @@ local CONF_INFERENCES = {
   latency_tokens = {typ = "boolean"},
   error_default_type = {enum = {"application/json", "application/xml",
                                 "text/html", "text/plain"}},
+  client_max_body_size = {typ = "string"},
+  client_body_buffer_size = {typ = "string"},
+
 
   database = {enum = {"postgres", "cassandra"}},
   pg_port = {typ = "number"},

kong/templates/kong_defaults.lua

@@ -31,6 +31,8 @@ upstream_keepalive = 60
 server_tokens = on
 latency_tokens = on
 error_default_type = text/plain
+client_max_body_size = 0
+client_body_buffer_size = 8k
 
 database = postgres
 pg_host = 127.0.0.1

kong/templates/nginx_kong.lua

@@ -19,7 +19,7 @@ error_log ${{PROXY_ERROR_LOG}} ${{LOG_LEVEL}};
 >-- reset_timedout_connection on; # disabled until benchmarked
 > end
 
-client_max_body_size 0;
+client_max_body_size ${{CLIENT_MAX_BODY_SIZE}};
 proxy_ssl_server_name on;
 underscores_in_headers on;
 
@@ -84,6 +84,7 @@ server {
     access_log ${{PROXY_ACCESS_LOG}};
     error_log ${{PROXY_ERROR_LOG}} ${{LOG_LEVEL}};
 
+    client_body_buffer_size ${{CLIENT_BODY_BUFFER_SIZE}};
 
 > if ssl then
     listen ${{PROXY_LISTEN_SSL}} ssl;

spec/01-unit/03-prefix_handler_spec.lua

@@ -141,6 +141,30 @@ describe("NGINX conf compiler", function()
       local nginx_conf = prefix_handler.compile_kong_conf(conf)
       assert.matches("error_log syslog:server=.+:61828 error;", nginx_conf)
     end)
+    it("defines the client_max_body_size by default", function()
+      local conf = assert(conf_loader(nil, {}))
+      local nginx_conf = prefix_handler.compile_kong_conf(conf)
+      assert.matches("client_max_body_size 0", nginx_conf, nil, true)
+    end)
+    it("writes the client_max_body_size as defined", function()
+      local conf = assert(conf_loader(nil, {
+        client_max_body_size = "1m",
+      }))
+      local nginx_conf = prefix_handler.compile_kong_conf(conf)
+      assert.matches("client_max_body_size 1m", nginx_conf, nil, true)
+    end)
+    it("defines the client_body_buffer_size directive by default", function()
+      local conf = assert(conf_loader(nil, {}))
+      local nginx_conf = prefix_handler.compile_kong_conf(conf)
+      assert.matches("client_body_buffer_size 8k", nginx_conf, nil, true)
+    end)
+    it("writes the client_body_buffer_size directive as defined", function()
+      local conf = assert(conf_loader(nil, {
+        client_body_buffer_size = "128k",
+      }))
+      local nginx_conf = prefix_handler.compile_kong_conf(conf)
+      assert.matches("client_body_buffer_size 128k", nginx_conf, nil, true)
+    end)
   end)
 
   describe("compile_nginx_conf()", function()

spec/fixtures/custom_nginx.template

@@ -29,7 +29,7 @@ http {
 >-- reset_timedout_connection on; # disabled until benchmarked
 > end
 
-    client_max_body_size 0;
+    client_max_body_size ${{CLIENT_MAX_BODY_SIZE}};
     proxy_ssl_server_name on;
     underscores_in_headers on;
 
@@ -92,6 +92,8 @@ http {
 
         access_log logs/access.log;
 
+        client_body_buffer_size ${{CLIENT_BODY_BUFFER_SIZE}};
+
 > if ssl then
         listen ${{PROXY_LISTEN_SSL}} ssl;
         ssl_certificate ${{SSL_CERT}};