tornado 5.0+ not compatible with gunicorn

[xyoun]

gunicorn version: 19.7.1
tornado: 5.0

failed with:

$ ./bin/gunicorn -w 1 -t 300 -k tornado web:app -b 0.0.0.0:9003
[2018-03-20 14:17:29 +0000] [28600] [INFO] Starting gunicorn 19.7.1
[2018-03-20 14:17:29 +0000] [28600] [INFO] Listening at: http://0.0.0.0:9003 (28600)
[2018-03-20 14:17:29 +0000] [28600] [INFO] Using worker: tornado
[2018-03-20 14:17:29 +0000] [28605] [INFO] Booting worker with pid: 28605
[2018-03-20 14:17:29 +0000] [28605] [ERROR] Exception in worker process
Traceback (most recent call last):
  File "/data/data/pkgs/nginxgw/nginxgw-45-838b8953/.buildout/eggs/gunicorn-19.7.1-py2.py3-none-any.ovo/gunicorn/arbiter.py", line 578, in spawn_worker
    worker.init_process()
  File "/data/data/pkgs/nginxgw/nginxgw-45-838b8953/.buildout/eggs/gunicorn-19.7.1-py2.py3-none-any.ovo/gunicorn/workers/base.py", line 131, in init_process
    self.run()
  File "/data/data/pkgs/nginxgw/nginxgw-45-838b8953/.buildout/eggs/gunicorn-19.7.1-py2.py3-none-any.ovo/gunicorn/workers/gtornado.py", line 70, in run
    PeriodicCallback(self.watchdog, 1000, io_loop=self.ioloop).start()
TypeError: __init__() got an unexpected keyword argument 'io_loop'
[2018-03-20 14:17:29 +0000] [28605] [INFO] Worker exiting (pid: 28605)
[2018-03-20 14:17:29 +0000] [28608] [INFO] Booting worker with pid: 28608
[2018-03-20 14:17:29 +0000] [28608] [ERROR] Exception in worker process
Traceback (most recent call last):
  File "/data/data/pkgs/nginxgw/nginxgw-45-838b8953/.buildout/eggs/gunicorn-19.7.1-py2.py3-none-any.ovo/gunicorn/arbiter.py", line 578, in spawn_worker
    worker.init_process()
  File "/data/data/pkgs/nginxgw/nginxgw-45-838b8953/.buildout/eggs/gunicorn-19.7.1-py2.py3-none-any.ovo/gunicorn/workers/base.py", line 131, in init_process
    self.run()
  File "/data/data/pkgs/nginxgw/nginxgw-45-838b8953/.buildout/eggs/gunicorn-19.7.1-py2.py3-none-any.ovo/gunicorn/workers/gtornado.py", line 70, in run
    PeriodicCallback(self.watchdog, 1000, io_loop=self.ioloop).start()
TypeError: __init__() got an unexpected keyword argument 'io_loop'

according to the release note of Tornado 5.0:

io_loop arguments to many Tornado functions have been removed. Use IOLoop.current() instead of passing IOLoop objects explicitly.

http://www.tornadoweb.org/en/stable/releases/v5.0.0.html#backwards-compatibility-notes

[castrapel]

I'm seeing this too.

[tilgovi]

If anyone can make a PR I'd be happy to review it.

[alviezhang]

@tilgovi I opened a pull request to fix this issue. #1752