Bear Classifier: There was an error when executing cell [4]. Please run Voilà with --debug to see the error message

Part 1 (2020)
1

Hi, I am unable to deploy the Bear Classifier app on mybinder. I get the following error:

There was an error when executing cell [4]. Please run Voilà with --debug to see the error message.

What is in that cell [4] of the notebook is:

path = Path()
learn_inf = load_learner(path/‘export.pkl’, cpu=True)
btn_upload = widgets.FileUpload()
out_pl = widgets.Output()
lbl_pred = widgets.Label()

My guess is that this issue comes from the line:

learn_inf = load_learner(path/‘export.pkl’, cpu=True)

Because I wrote it on my own machine (Windows), I was getting an error due to / versus \ in the path name. So I added the following cell to fix that:

import pathlib
temp = pathlib.PosixPath
pathlib.PosixPath = pathlib.WindowsPath

And everything works well with Voila.
However, myBinder doesn’t seem to get it. Any idea?

PS: I had to run voila from my own machine because it doesn’t seem to work on the Paperspace’s ones

2

Problem solved!
The issue was this portion of code that I had added:

import pathlib
temp = pathlib.PosixPath
pathlib.PosixPath = pathlib.WindowsPath

This portion was necessary for testing my program on my machine (Windows), but then, before uploading the notebook to github for app deployment (myBinder) I should remove that portion of code.

1 Like
3

Really interested in this. But can you be more specific? I added this piece of code but nothing worked for me. Can you re explain for those who might come across this issue? :slight_smile:

4

Hi,
I downloaded the code from Paperspace and ran it locally on my machine (Windows) using Jupyter Notebook. And for it to run on a Windows environment, I had to add the following piece:

import pathlib
temp = pathlib.PosixPath
pathlib.PosixPath = pathlib.WindowsPath

Note that I had also installed Voila on my local environment/machine.
I was then able to test the code using Voila on my local machine.
The reason I decided to test on my local machine is that, for some reason Voila wasn’t working for me in Paperspace.
Now, after testing the code in my local machine, I had to remove piece of code presented above before uploading the Bear classifier code onto github and using myBinder.

5

If you facing this on the Heroku server. try to update fastai version. I faced the same issue then I upgraded to fastai==2.3.1

6

How to Deploy Fast.ai Models? (Voilà , Binder and Heroku)

Medium article:
https://medium.com/unpackai/how-to-deploy-fast-ai-models-8704ea711ad2

code:

I hope this may help.