Client instantiation AssertionError #580

fonnesbeck opened this Issue Jul 14, 2011 · 2 comments


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I've just built iPython from the latest master source to try out the parallel computing. However, I am unable to instantiate a Client:

from IPython.parallel import Client

c =Client()
AssertionError                            Traceback (most recent call last)
/Users/fonnescj/<ipython-input-2-129bd7281f19> in <module>()
----> 1 c =Client()

/Library/Python/2.6/site-packages/ in __init__(self, url_or_file, profile, profile_dir, ipython_dir, context, debug, exec_key, sshserver, sshkey, password, paramiko, timeout, **extra_args)
    313                 if self._cd:
    314                     url_or_file = os.path.join(self._cd.security_dir, url_or_file)
--> 315                 assert os.path.exists(url_or_file), "Not a valid connection file or url: %r"%url_or_file
    316             with open(url_or_file) as f:
    317                 cfg = json.loads(

AssertionError: Not a valid connection file or url: u'/Users/fonnescj/.config/ipython/profile_default/security/ipcontroller-client.json'

I'm hoping this is just a simple error on my part.

Running on OS X 10.6.7 with Python 2.6.1 that ships with OS X.

minrk commented Jul 14, 2011

Do you have a controller running? The client is balking because there is no file containing information to connect to a controller, which would suggest that you have never started a controller.

Start a cluster with:

ipcluster start --n=4

Then try creating a Client.


Thought I had done that, but perhaps it crashed, as it seems to be working now. Thanks.

@fonnesbeck fonnesbeck closed this Jul 14, 2011
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