feat(proxy) add service.request_buffering

### Summary

By default Kong does buffer the request. This is not ideal when proxying
bigger payloads with HTTP 1.1 chunked encoding.

This commit adds a new property to service entity:
```
request_buffering = <true/false>
```

By default that is `true` (which is the same as before). Users can now
turn off the request buffering on service-by-service manner by setting
`service.request_buffering=false`.

autodoc/data/admin-api.lua

@@ -653,6 +653,13 @@ return {
             for transmitting a request to the upstream server.
           ]]
         },
+        request_buffering = {
+          description = [[
+            Whether to enable request body buffering or not. With HTTP 1.1, it
+            may make sense to turn this off on services that receive data with
+            chunked transfer encoding.
+          ]]
+        },
         client_certificate = {
           description = [[
             Certificate to be used as client certificate while TLS handshaking

kong-2.0.4-0.rockspec

@@ -197,6 +197,7 @@ build = {
     ["kong.db.migrations.core.007_140_to_150"] = "kong/db/migrations/core/007_140_to_150.lua",
     ["kong.db.migrations.core.008_150_to_200"] = "kong/db/migrations/core/008_150_to_200.lua",
     ["kong.db.migrations.core.009_200_to_210"] = "kong/db/migrations/core/009_200_to_210.lua",
+    ["kong.db.migrations.core.010_210_to_220"] = "kong/db/migrations/core/010_210_to_220.lua",
     ["kong.db.migrations.operations.200_to_210"] = "kong/db/migrations/operations/200_to_210.lua",
 
     ["kong.pdk"] = "kong/pdk/init.lua",

kong/db/migrations/core/010_210_to_220.lua

@@ -0,0 +1,19 @@
+return {
+  postgres = {
+    up = [[
+      DO $$
+      BEGIN
+        ALTER TABLE IF EXISTS ONLY "services" ADD "request_buffering" BOOLEAN;
+      EXCEPTION WHEN DUPLICATE_COLUMN THEN
+        -- Do nothing, accept existing state
+      END;
+      $$;
+    ]],
+  },
+
+  cassandra = {
+    up = [[
+      ALTER TABLE services ADD request_buffering boolean;
+    ]],
+  },
+}

kong/db/migrations/core/init.lua

@@ -7,4 +7,5 @@ return {
   "007_140_to_150",
   "008_150_to_200",
   "009_200_to_210",
+  "010_210_to_220",
 }

kong/db/schema/entities/services.lua

@@ -38,6 +38,7 @@ return {
     { connect_timeout    = nonzero_timeout { default = 60000 }, },
     { write_timeout      = nonzero_timeout { default = 60000 }, },
     { read_timeout       = nonzero_timeout { default = 60000 }, },
+    { request_buffering  = { type = "boolean", required = true, default = true }, },
     { tags               = typedefs.tags },
     { client_certificate = { type = "foreign", reference = "certificates" }, },
     { tls_verify         = { type = "boolean", }, },

kong/init.lua

@@ -648,8 +648,9 @@ end
 
 
 function Kong.rewrite()
-  if var.kong_proxy_mode == "grpc" then
-    kong_resty_ctx.apply_ref() -- if kong_proxy_mode is gRPC, this is executing
+  local proxy_mode = var.kong_proxy_mode
+  if proxy_mode == "grpc" or proxy_mode == "unbuffered"  then
+    kong_resty_ctx.apply_ref() -- if kong_proxy_mode is gRPC/unbuffered, this is executing
     kong_resty_ctx.stash_ref() -- after an internal redirect. Restore (and restash)
                                -- context to avoid re-executing phases
 

kong/reports.lua

@@ -217,7 +217,7 @@ local function get_current_suffix(ctx)
   local scheme = var.scheme
   local proxy_mode = var.kong_proxy_mode
   if scheme == "http" or scheme == "https" then
-    if proxy_mode == "http" then
+    if proxy_mode == "http" or proxy_mode == "unbuffered" then
       local http_upgrade = var.http_upgrade
       if http_upgrade and lower(http_upgrade) == "websocket" then
         if scheme == "http" then

kong/runloop/handler.lua

@@ -1219,6 +1219,10 @@ return {
         if service.protocol == "grpcs" then
           return ngx.exec("@grpcs")
         end
+
+        if service.request_buffering == false and http_version == 1.1 then
+          return ngx.exec("@unbuffered")
+        end
       end
     end,
     -- Only executed if the `router` module found a route and allows nginx to proxy it.

kong/templates/nginx_kong.lua

@@ -137,7 +137,38 @@ server {
         set $upstream_x_forwarded_prefix '';
         set $kong_proxy_mode             'http';
 
-        proxy_http_version    1.1;
+        proxy_http_version      1.1;
+        proxy_request_buffering on;
+
+        proxy_set_header      TE                 $upstream_te;
+        proxy_set_header      Host               $upstream_host;
+        proxy_set_header      Upgrade            $upstream_upgrade;
+        proxy_set_header      Connection         $upstream_connection;
+        proxy_set_header      X-Forwarded-For    $upstream_x_forwarded_for;
+        proxy_set_header      X-Forwarded-Proto  $upstream_x_forwarded_proto;
+        proxy_set_header      X-Forwarded-Host   $upstream_x_forwarded_host;
+        proxy_set_header      X-Forwarded-Port   $upstream_x_forwarded_port;
+        proxy_set_header      X-Forwarded-Prefix $upstream_x_forwarded_prefix;
+        proxy_set_header      X-Real-IP          $remote_addr;
+        proxy_pass_header     Server;
+        proxy_pass_header     Date;
+        proxy_ssl_name        $upstream_host;
+        proxy_ssl_server_name on;
+> if client_ssl then
+        proxy_ssl_certificate ${{CLIENT_SSL_CERT}};
+        proxy_ssl_certificate_key ${{CLIENT_SSL_CERT_KEY}};
+> end
+        proxy_pass            $upstream_scheme://kong_upstream$upstream_uri;
+    }
+
+    location @unbuffered {
+        internal;
+        default_type         '';
+        set $kong_proxy_mode 'unbuffered';
+
+        proxy_http_version      1.1;
+        proxy_request_buffering off;
+
         proxy_set_header      TE                 $upstream_te;
         proxy_set_header      Host               $upstream_host;
         proxy_set_header      Upgrade            $upstream_upgrade;

spec/01-unit/01-db/01-schema/05-services_spec.lua

@@ -124,12 +124,13 @@ describe("services", function()
     -- acceptance
     it("should be greater than zero", function()
       local service = {
-        host            = "example.com",
-        port            = 80,
-        protocol        = "https",
-        connect_timeout = 1,
-        read_timeout    = 10,
-        write_timeout   = 100,
+        host              = "example.com",
+        port              = 80,
+        protocol          = "https",
+        connect_timeout   = 1,
+        read_timeout      = 10,
+        write_timeout     = 100,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -240,6 +241,7 @@ describe("services", function()
         host = "example.com",
         path = "/",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -253,6 +255,7 @@ describe("services", function()
         host = "example.com",
         path = "/abcd~user~2",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -269,6 +272,7 @@ describe("services", function()
           host = "example.com",
           path = valid_paths[i],
           port = 80,
+          request_buffering = true,
         }
 
         local ok, err = Services:validate(service)
@@ -283,6 +287,7 @@ describe("services", function()
         host = "example.com",
         path = "/ovo/",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -395,6 +400,7 @@ describe("services", function()
           protocol = "http",
           host = valid_hosts[i],
           port = 80,
+          request_buffering = true,
         }
 
         local ok, err = Services:validate(service)
@@ -437,6 +443,7 @@ describe("services", function()
       for i = 1, #invalid_names do
         local service = {
           name = invalid_names[i],
+          request_buffering = true,
         }
 
         local ok, err = Services:validate(service)
@@ -465,7 +472,8 @@ describe("services", function()
           protocol = "http",
           host = "example.com",
           port = 80,
-          name = valid_names[i]
+          name = valid_names[i],
+          request_buffering = true,
         }
 
         local ok, err = Services:validate(service)
@@ -481,6 +489,7 @@ describe("services", function()
         protocol = "tcp",
         host = "x.y",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -493,6 +502,7 @@ describe("services", function()
         protocol = "tls",
         host = "x.y",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -505,6 +515,7 @@ describe("services", function()
         protocol = "grpc",
         host = "x.y",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)
@@ -517,6 +528,7 @@ describe("services", function()
         protocol = "grpcs",
         host = "x.y",
         port = 80,
+        request_buffering = true,
       }
 
       local ok, err = Services:validate(service)

spec/01-unit/01-db/01-schema/11-declarative_config/02-process_auto_fields_spec.lua

@@ -59,6 +59,7 @@ describe("declarative config: process_auto_fields", function()
               read_timeout = 60000,
               write_timeout = 60000,
               retries = 5,
+              request_buffering = true,
               _comment = "my comment",
               _ignore = { { foo = "bar" } },
             },
@@ -71,6 +72,7 @@ describe("declarative config: process_auto_fields", function()
               read_timeout = 60000,
               write_timeout = 60000,
               retries = 5,
+              request_buffering = true,
               _comment = "my comment",
               _ignore = { { foo = "bar" } },
             }
@@ -101,6 +103,7 @@ describe("declarative config: process_auto_fields", function()
               read_timeout = 60000,
               write_timeout = 60000,
               retries = 5,
+              request_buffering = true,
             }
           }
         }, config)
@@ -250,6 +253,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 plugins = {}
               }
             }
@@ -298,6 +302,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 _comment = "my comment",
                 _ignore = { { foo = "bar" } },
                 plugins = {
@@ -340,6 +345,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 plugins = {
                   {
                     name = "basic-auth",
@@ -391,6 +397,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 routes = {}
               }
             }
@@ -438,6 +445,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 routes = {
                   {
                     paths = { "/path" },
@@ -477,6 +485,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 routes = {
                   {
                     paths = { "/path" },
@@ -524,6 +533,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 routes = {
                   {
                     name = "foo",
@@ -587,6 +597,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 routes = {
                   {
                     name = "foo",
@@ -637,6 +648,7 @@ describe("declarative config: process_auto_fields", function()
                 read_timeout = 60000,
                 write_timeout = 60000,
                 retries = 5,
+                request_buffering = true,
                 routes = {
                   {
                     name = "bar",