Empty reply from server when setup with uwsgi

I try to setup omnibus-gitlab but with uwsgi (I already use uwsgi for everything, so it's nice to use with gitlab because I will get auto inventory for monitoring).

I install gitlab, and modify /etc/gitlab/gitlab.rb and run gitlab-ctl reconfigure.

# Change the external_url to the address your users will type in their browser
external_url 'http://gitlab.example.com'
nginx['enable'] = false
unicorn['enable'] = false

I download latest uwsgi 2.0.7 and compile with gitlab's embbeded ruby.

# UWSGI_INCLUDES=/opt/gitlab/embedded/include UWSGICONFIG_RUBYPATH=/opt/gitlab/embedded/bin/ruby python uwsgiconfig.py --build

The build run successful, return no erros.

After that I run uwsgi with config:

uwsgi:
  socket: 127.0.0.1:3132
  uid: git
  gid: git
  rack: config.ru
  master: true
  processes: 2
  lazy-apps: true
  chdir: /opt/gitlab/embedded/service/gitlab-rails
  buffer-size: 32768
  post-buffering: 4096
  rbrequire: rubygems
  rbrequire: bundler/setup
  env: BUNDLE_GEMFILE=/opt/gitlab/embedded/service/gitlab-rails/Gemfile
  env: RAILS_ENV=production

uwsgi seems to start fine

Sep 29 08:58:05 dev-1 uwsgi: *** Starting uWSGI 2.0.7 (64bit) on [Mon Sep 29 08:58:05 2014] ***
Sep 29 08:58:05 dev-1 uwsgi: compiled with version: 4.6.3 on 29 September 2014 07:16:13
Sep 29 08:58:05 dev-1 uwsgi: os: Linux-3.13.0-32-generic #57~precise1-Ubuntu SMP Tue Jul 15 03:51:20 UTC 2014
Sep 29 08:58:05 dev-1 uwsgi: nodename: dev-1
Sep 29 08:58:05 dev-1 uwsgi: machine: x86_64
Sep 29 08:58:05 dev-1 uwsgi: clock source: unix
Sep 29 08:58:05 dev-1 uwsgi: detected number of CPU cores: 2
Sep 29 08:58:05 dev-1 uwsgi: current working directory: /etc/uwsgi
Sep 29 08:58:05 dev-1 uwsgi: detected binary path: /usr/local/uwsgi-2.0.7/uwsgi
Sep 29 08:58:05 dev-1 uwsgi: !!! no internal routing support, rebuild with pcre support !!!
Sep 29 08:58:05 dev-1 uwsgi: your processes number limit is 15848
Sep 29 08:58:05 dev-1 uwsgi: your memory page size is 4096 bytes
Sep 29 08:58:05 dev-1 uwsgi: detected max file descriptor number: 1024
Sep 29 08:58:05 dev-1 uwsgi: lock engine: pthread robust mutexes
Sep 29 08:58:05 dev-1 uwsgi: thunder lock: disabled (you can enable it with --thunder-lock)
Sep 29 08:58:05 dev-1 uwsgi: uwsgi socket 0 bound to TCP address 127.0.0.1:3132 fd 3
Sep 29 08:58:05 dev-1 uwsgi: setgid() to 1000
Sep 29 08:58:05 dev-1 uwsgi: setuid() to 1000
Sep 29 08:58:06 dev-1 uwsgi: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
Sep 29 08:58:06 dev-1 uwsgi: your server socket listen backlog is limited to 100 connections
Sep 29 08:58:06 dev-1 uwsgi: your mercy for graceful operations on workers is 60 seconds
Sep 29 08:58:06 dev-1 uwsgi: mapped 328872 bytes (321 KB) for 2 cores
Sep 29 08:58:06 dev-1 uwsgi: *** Operational MODE: preforking ***
Sep 29 08:58:06 dev-1 uwsgi: *** uWSGI is running in multiple interpreter mode ***
Sep 29 08:58:06 dev-1 uwsgi: spawned uWSGI master process (pid: 4220)
Sep 29 08:58:06 dev-1 uwsgi: Mon Sep 29 08:58:06 2014 - [emperor] vassal gitlab.yml has been spawned
Sep 29 08:58:06 dev-1 uwsgi: spawned uWSGI worker 1 (pid: 4222, cores: 1)
Sep 29 08:58:06 dev-1 uwsgi: spawned uWSGI worker 2 (pid: 4223, cores: 1)
Sep 29 08:58:10 dev-1 uwsgi: [deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.
Sep 29 08:58:10 dev-1 uwsgi: 
Sep 29 08:58:10 dev-1 uwsgi: [deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.
Sep 29 08:58:10 dev-1 uwsgi: 
Sep 29 08:58:14 dev-1 uwsgi: RACK app 0 loaded in 8 seconds at 0x1020 (GC frequency: AGGRESSIVE)
Sep 29 08:58:14 dev-1 uwsgi: Mon Sep 29 08:58:14 2014 - [emperor] vassal gitlab.yml is ready to accept requests
Sep 29 08:58:14 dev-1 uwsgi: RACK app 0 loaded in 8 seconds at 0x1020 (GC frequency: AGGRESSIVE)

But when I test, the server returns empty response.

# curl 127.0.0.1:3132
curl: (52) Empty reply from server

So anyone can tell me what I did wrong? Or how to debug this problem?