TypeError when importing modin

[ek-nath]

System information

• Amazon linux (Centos):
• Modin installed from binary:
• Modin version: 0.2.2:
• Python version: 3.7.0:
• Ray version: 0.5.3
• import modin.pandas:

Describe the problem

I am getting an import error because of an unexpected argument use_raylet

Source code / logs

In [1]: import modin.pandas
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-1-d42df328a6c7> in <module>()
----> 1 import modin.pandas

~/anaconda3/lib/python3.7/site-packages/modin/pandas/__init__.py in <module>()
     78             include_webui=False,
     79             redirect_worker_output=True,
---> 80             use_raylet=True,
     81         )
     82 except AssertionError:

TypeError: init() got an unexpected keyword argument 'use_raylet'

[devin-petersohn]

What is your Ray version?

import ray
ray.__version__

[devin-petersohn]

Hi @ek-nath, I did a bit more digging. It looks like you may have recently built Ray from source. We depend on the pypi release of Ray, and the ray.init API changed slightly since the last Ray release. If you want to resolve this issue, you will have to install Ray using pip (pip install ray).

cc @robertnishihara

[ek-nath]

I have updated the original issue report with the version. It is 0.5.3

[ek-nath]

installing ray via pip doesn't seem to resolve the issue either. I will try to check with an older version of ray and report back

[devin-petersohn]

You may need to pip uninstall ray; pip install ray.

[ek-nath]

This is weird. I am unable to install ray at all using pip.

dev-machine % pip install ray       
Collecting ray
  Could not find a version that satisfies the requirement ray (from versions: )
No matching distribution found for ray

(18-10-31 20:11:08) <1> [~]  
dev-machine % pip install ray==0.5.3
Collecting ray==0.5.3
  Could not find a version that satisfies the requirement ray==0.5.3 (from versions: )
No matching distribution found for ray==0.5.3

(18-10-31 20:11:10) <1> [~]  

[ek-nath]

Was able to install using pip install -U https://s3-us-west-2.amazonaws.com/ray-wheels/latest/ray-0.5.3-cp37-cp37m-manylinux1_x86_64.whl based on instructions here

But the problem of the use_raylet persists and like it says in the URL, it installs version 0.5.3

[devin-petersohn]

Oh, it is a Python 3.7 issue. Ray 0.5.3 on pypi did not ship with Python 3.7 support.

There is a PR that will resolve this use_raylet issue: ray-project/ray#3176, and once it gets merged the nightly wheels (where you installed from) will reflect that change.

In the meantime, it is possible to install this way:

pip install git+https://github.com/devin-petersohn/modin/@no_raylet

I pushed a branch that removes the use_raylet option to my fork of Modin. Everything else is identical to current master. You can keep your installation of Ray and install this way and it should work.

[ek-nath]

Success @devin-petersohn

python -c "import modin.pandas"
Process STDOUT and STDERR is being redirected to /tmp/ray/session_2018-10-31_20-41-01_29838/logs.
Waiting for redis server at 127.0.0.1:12739 to respond...
Waiting for redis server at 127.0.0.1:17503 to respond...
Starting the Plasma object store with 6.4900694009999995 GB memory using /dev/shm.