Question

Am getting the below error when executing python protocols/smpp/test/test_post_upgrade.py:

Traceback (most recent call last):
  File "protocols/smpp/test/test_post_upgrade.py", line 1, in <module>
    from protocols.smpp.proto import *
  File "/tmp/Wass/protocols/smpp/proto.py", line 1, in <module>
    from twisted.internet import defer, reactor
ImportError: No module named internet

Here’s my tree:

/tmp/Wass$ tree
.
├── __init__.py
└── protocols
    ├── __init__.py
    ├── __init__.pyc
    └── smpp
        ├── __init__.py
        ├── __init__.pyc
        ├── proto.py
        ├── proto.pyc
        └── test
            ├── __init__.py
            └── test_post_upgrade.py

3 directories, 10 files

Here’s the content of the principal files:

/tmp/Wass$ cat protocols/smpp/proto.py
from twisted.internet import defer, reactor

/tmp/Wass$ cat protocols/smpp/test/test_post_upgrade.py 
from protocols.smpp.proto import *

/tmp/Wass$ cat protocols/smpp/__init__.py
__import__('pkg_resources').declare_namespace(__name__)

For information, i can resolve this issue by one of these actions:

• Emptying protocols/smpp/__init__.py, but this is usefull for the whole project so i can just empty this file, my project will no more run ..
• Renaming protocols/smpp to anything else, for example protocols/toto will work (with changing protocols/smpp/test/test_post_upgrade.py to from protocols.toto.proto import *

The second solution is so confusing as i dont have any smpp/proto.py in my system that can cause a conflict …

Here’s a simpler representation of the issue:

Wass/
Wass/__init__.py
Wass/protocols/
Wass/protocols/smpp/
Wass/protocols/smpp/__init__.py
Wass/protocols/smpp/test/
Wass/protocols/smpp/test/__init__.py
Wass/protocols/__init__.py

Wass/protocols/smpp/test/test_post_upgrade.py:
> from Wass.protocols.smpp.proto import SMPPClientProtocol

Wass/protocols/smpp/proto.py
> from twisted.internet import defer, reactor
>
> class SMPPClientProtocol:
>     pass

Execution outcome:

$ echo $PYTHONPATH
:/opt/smpp.twisted/:/opt/smpp.pdu/:/tmp/Wass/
python /tmp/Wass/protocols/smpp/test/test_post_upgrade.py
> Returns the same problem above

Answer 1

There are a number of potential issues here.

1. Is Wass really supposed to be a package, or is it an entry on sys.path? If it’s really a package, you should be adding /tmp to your PYTHONPATH; if it’s a path entry, you should be adding /tmp/Wass to PYTHONPATH, and deleting /tmp/Wass/__init__.py*.
2. Don’t run python on modules within a hierarchy directly. It confuses the issue.
3. If Wass is going to continue to be a package (i.e. contain an __init__.py), you should adjust your imports to be from Wass.protocols.smpp.proto import ....
4. Don’t use import *. It’s just confusing; someone reading your code has no idea what names are supposed to come from what module.
5. Try to simplify this as much as possible, and upload a complete, runnable example of a set of files that causes the problem. Since I don’t know what’s inside those .py files, I have to guess at the cause.

Ultimately I think that the problem you’re seeing is caused by the combination of a top-level module named protocols, which conflicts with several modules within Twisted, and the use of import * which is probably pulling in another name like basic or smtp or pop3 into that namespace and clashing with something, then the magic of namespace packages combines with it all to create an explosion. I can’t be more specific than that without seeing the actual code that triggers the problem :).

Whenever faced with an issue like this though, it’s good to take a step back and make sure that the working directory, the script directory, and PYTHONPATH are all separated out so you know exactly how your code is being imported. Specifically, I’d recommend doing something like this:

$ cd /tmp
$ mkdir runstuff
$ cd runstuff
$ PYTHONPATH=/tmp/Wass trial protocols

Hopefully that will work out better for you.