ImportError: No module named cv_bridge_boost on Mac OS X

[venabled]

This seems to be related to ros-perception/image_pipeline#34

We (myself and @kyonifer) built groovy-dekstop using MacPorts on OS X 10.7.5 , and on using opencv_bridge (version 1.10.7) in python get the message:

ImportError: No module named cv_bridge_boost

More guessing that it has to do with something not detecting that cv_bridge_boost.dylib is created when compiling on the Mac vs cv_bridge_boost.so.

The library is compiled, and exists under $PYTHON_PATH at /opt/local/lib/python2.7/site-packages/cv_bridge/boost

edward:cv_bridge venabled$ ls -l /opt/local/lib/python2.7/site-packages/cv_bridge/boost
total 320
-rw-r--r--  1 root  admin       0 Aug  7 17:54 __init__.py
-rwxr-xr-x  1 root  admin  160988 Aug  7 17:55 cv_bridge_boost.dylib

Full code traceback:

Traceback (most recent call last):
  File "./evaluate_pnp.py", line 221, in <module>
    aspn_meas = np.array(bridge.imgmsg_to_cv(msg))
  File "/opt/local/lib/python2.7/site-packages/cv_bridge/core.py", line 101, in imgmsg_to_cv
    source_type = self.encoding_as_cvtype(img_msg.encoding)
  File "/opt/local/lib/python2.7/site-packages/cv_bridge/core.py", line 73, in encoding_as_cvtype
    from cv_bridge.boost.cv_bridge_boost import getCvType
ImportError: No module named cv_bridge_boost

[vrabaud]

Yes indeed. I have no experience with Mac. @wjwwood , any input on that ? Thx. It seems Python modules have to be named .so
http://mail.python.org/pipermail/pythonmac-sig/2007-February/018677.html
I could not find anything really firm about it though.

[wjwwood]

Sounds plausible, @venabled can you try just renaming the installed .dylib file to .so?

[wjwwood]

Or better yet use a symbolic link?

[vrabaud]

can you please check how other libraries do their Python compiled libraries ? e.g., is it cv2.so or dylib for OpenCV ?

[wjwwood]

It is .so:

/Users/william/hydro/install_isolated/lib/python2.7/site-packages/cv2.so

[venabled]

It ends up with a SegFault if I do either symlink, or create a copy of the thing:

Segmentation fault: 11

Here's what the directory looks like:

edward:boost venabled$ ls -l
total 328
-rw-r--r--  1 root  admin       0 Aug  7 17:54 __init__.py
-rwxr-xr-x  1 root  admin  160988 Aug  7 17:55 cv_bridge_boost.dylib
lrwxr-xr-x  1 root  admin      23 Aug 12 15:41 cv_bridge_boost.so -> ./cv_bridge_boost.dylib

[vrabaud]

ok, we're getting somewhere :) So that is the main issue. @wjwwood , you are aware of that .so .dylib issue ? Should there be a catkin variable to set the shared library extension ?

For your segfault @venabled , any way you could gdb that ?

[wjwwood]

I vaguely remember it, I think that I have made a similar fix in either moveit or rqt.

[wjwwood]

Yup:

https://github.com/ros-visualization/rviz/blob/hydro-devel/src/python_bindings/sip/CMakeLists.txt#L59

[vrabaud]

can you guys please try the fix ? (that should fix the import). There is still the segfault apparently, please provide a backtrace for that.
Thx @wjwwood for your insight. I like my fix better though :)

[venabled]

I am a gdb newb, but here's my backtrace:

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000
0x0000000000000000 in ?? ()
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x00000001123bf928 in PyEval_GetGlobals ()
#2  0x00000001123d7479 in PyImport_Import ()
#3  0x00000001123d7612 in PyImport_ImportModule ()
#4  0x000000010d6cdc70 in init_module_cv_bridge_boost ()
#5  0x0000000111e2e8e7 in boost::python::handle_exception_impl ()
#6  0x0000000111e2f95b in boost::python::handle_exception<void (*)()> ()
#7  0x0000000111e2f832 in boost::python::detail::init_module ()
#8  0x000000010d6cdc4b in initcv_bridge_boost ()
#9  0x00000001000bdb21 in _PyImport_LoadDynamicModule ()
#10 0x00000001000bd854 in import_submodule ()
#11 0x00000001000bd3dc in load_next ()
#12 0x00000001000bb32f in PyImport_ImportModuleLevel ()
#13 0x000000010009b758 in builtin___import__ ()
#14 0x00000001000118b1 in PyObject_Call ()
#15 0x00000001000a7338 in PyEval_CallObjectWithKeywords ()
#16 0x00000001000a48f2 in PyEval_EvalFrameEx ()
#17 0x00000001000a7b22 in fast_function ()
#18 0x00000001000a2d38 in PyEval_EvalFrameEx ()
#19 0x00000001000a0596 in PyEval_EvalCodeEx ()
#20 0x00000001000a7b8d in fast_function ()
#21 0x00000001000a2d38 in PyEval_EvalFrameEx ()
#22 0x00000001000a0596 in PyEval_EvalCodeEx ()
#23 0x000000010009fdc6 in PyEval_EvalCode ()
#24 0x00000001000c6e3e in PyRun_FileExFlags ()
#25 0x00000001000c69a0 in PyRun_SimpleFileExFlags ()
#26 0x00000001000da7a8 in Py_Main ()
#27 0x0000000100001f24 in dyld_stub_strlen ()
(gdb) quit

Was also getting a bunch of warnings from gdb in finding different object files related to boost.

[vrabaud]

wait, so you still got the bug after my fix ? Should I reopen ? @wjwwood does that work for you ? thx

[wjwwood]

I think this is a separate issue, I haven't reproduced it locally, but it looks like a segfault in the boost python wrapper. I would open a new issue for this (The original problem has been solved here).

[wjwwood]

After doing the symbolic link I can do the import:

william@dosa:~
% hydro

william@dosa:~
% python
Python 2.7.2 (default, Oct 11 2012, 20:14:37)
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from cv_bridge.boost.cv_bridge_boost import getCvType
>>>

[vrabaud]

thx @wjwwood . @venabled , does it work for you too now ?

[venabled]

No sorry guys. Same segfault.

levin:bags venabled$ python
Python 2.7.5 (default, Aug  1 2013, 01:01:17)
[GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from cv_bridge.boost.cv_bridge_boost import getCvType
Segmentation fault: 11

I agree with @wjwwood that it's probably something with boost::python due to the backtrace above (maybe due to the specific version of boost::python we're using in macports)

I haven't put a lot of work into figuring it out and just bypassed cv_bridge for python and used PIL/numpy/opencv do do what I need to.

[wjwwood]

I am using Homebrew, which uses boost 1.53.0 or 1.54.0 and the system provided Python, but other than that I don't know how they are different.