ImportError: No module named 'sling.pysling'

[FlorianPfisterer]

System

• Ubuntu 16.04.2 LTS
• python --version: Python 2.7.12
• python3 --version: Python 3.5.2

I have cloned the sling repository (master branch), run the setup.sh script (which was successful) and then started a python3 session. When I type import sling it throws the following error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/sling/__init__.py", line 1, in <module>
    import sling.pysling as api
ImportError: No module named 'sling.pysling'

The same error occurs when I run the training script (sling/nlp/parser/tools/train.sh), which I have modified to use python3 instead of python (just replace the Python command in the second to last line):

Traceback (most recent call last):
  File "sling/nlp/parser/tools/train_pytorch.py", line 18, in <module>
    import sling
  File "/usr/lib/python3/dist-packages/sling/__init__.py", line 1, in <module>
    import sling.pysling as api
ImportError: No module named 'sling.pysling'
Done. Log is available at test_train_1/log.

What am I doing wrong?

[ringgaard]

It looks like you did it the right way, but something went wrong. My guess is that pysling.so file is missing in the python directory.

The setup.sh script will create a symbolic link from /usr/lib/python3/dist-packages/sling to the python subdirectory in your repo directory (unless this directory already exists), e.g.:

$ ls -l /usr/lib/python3/dist-packages/sling
lrwxrwxrwx 1 root root 28 May  7 15:51 /usr/lib/python3/dist-packages/sling -> /home/$USER/sling/python

The python subdirectory then contains a symbolic link to pysling.so:

$ ls -l /home/$USER/sling/python/
lrwxrwxrwx 1 michael staff    35 Jan  4  2018 pysling.so -> ../bazel-bin/sling/pyapi/pysling.so

Can I get you to check that this chain of symbolic links are properly installed on your machine?

PS: I will get the python->python3 bug fixed in the training script.

[FlorianPfisterer]

Thanks for the fast reply! I investigated sling/python/pysling.so more and this led me to the problem: The setup.sh script was actually not the problem. I noticed that when transferring the sling folder via FTP to the remote machine, sling/python/pysling.so could not be transferred for some reason. When cloning the repository from GitHub to the remote machine directly, it worked.

[ringgaard]

Sounds good. As mentioned, the repo has a few symbolic links, and these can probably not be copied using FTP.