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 +185,27 @@
                                   # `text/html`, `application/json`, and
                                   # `application/xml`.
 
+#client_max_body_size = 0        # Defines the maximum request body size allowed
+                                 # 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 of request body size.
+
+#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.
+
 #------------------------------------------------------------------------------
 # DATASTORE
 #------------------------------------------------------------------------------

kong/conf_loader.lua

@@ -70,6 +70,7 @@ 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"},
 
   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;