Actor not printing when launched in jupyter

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Linux Ubuntu 16.04
• Ray installed from (source or binary): pip3 install ray
• Ray version: 0.6.1
• Python version: 3.5.2
• Exact command to reproduce: run following code from inside a Jupyter notebook or from a vanilla python file

Describe the problem

Printing inside actors should show up in the stdout/stdrr or at least in logs when launched from inside a Jupyter notebook. For the moment, nothing is visible.

Source code / logs

import ray
ray.init()

@ray.remote
class Counter(object):
    def __init__(self):
        self.value = 0

    def increment(self):
        self.value += 1
        print(self.value)
        return self.value
    
c = Counter.remote()
print(ray.get(c.increment.remote()))

Give 1 then 1 when python3 test.py but only 1 inside notebook.

[robertnishihara]

Interesting, I can reproduce it. The actor print statements seem to be redirected to my terminal where I ran jupyter-notebook (also it wasn’t flushed immediately).

I can reproduce it even more easily in a Jupyter notebook just by running

import subprocess
subprocess.Popen(['ls'])

That will show up in the terminal where you started the jupyter-notebook and not in the notebook itself.

[ErikEngerd]

Still not working for me. Using ray 1.1.0

ray.init(ignore_reinit_error=True)
@ray.remote
def getcwd():
    cwd = os.path.realpath(".")
    print(cwd)
    return cwd
ray.get(getcwd.remote())

OS: centos 7

> pip list | grep jupyter
jupyter                            1.0.0              
jupyter-client                     5.3.4              
jupyter-console                    6.1.0              
jupyter-contrib-core               0.3.3              
jupyter-contrib-nbextensions       0.5.1              
jupyter-core                       4.6.1              
jupyter-highlight-selected-word    0.2.0              
jupyter-latex-envs                 1.4.6              
jupyter-nbextensions-configurator  0.4.1              
jupyterlab                         1.2.6              
jupyterlab-server                  1.0.6   

The weird thing is that I see the expected output when I use the jupyter-lab interface but not when using the old jupyter notebook interface. So switching to the new interface fixes the issue. To be specific: new interface is the lab URL (animation when launching), old interface is the tree URL.