Add arch-specific library folders (#154)

[scpeters]

Try to detect arch-specific library folders using
gcc and dpkg-architecture, then add to
LD_LIBRARY_PATH and PKG_CONFIG_PATH.
Closes #154.
Based on ros/catkin#624

[scpeters]

Which package do I need to install to run nosetests?

[wjwwood]

sudo apt-get install python-nose on Ubuntu or sudo -H pip install -U nose on OS X.

[scpeters]

Ok, I have that installed, but when I do python setup.py nosetests, it says error: invalid command 'nosetests'

[scpeters]

That command was recommended in #90

[scpeters]

oops indentation...

[wjwwood]

What operating system?

[scpeters]

Ubuntu trusty

[wjwwood]

I can run python setup.py nosetests in the root of the catkin_tools directory on my VM of Trusty and on my Mac. I'm not sure why it doesn't work for you. Make sure you've installed nose for the same instance of python that you're using.

[scpeters]

It was a venv problem; it's working now.

[scpeters]

With python 2.7 on trusty, starting in catkin_tools source repo root:

$ virtualenv $HOME/local
$ . ~/local/bin/activate
$ python setup.py install
$ pip install argparse catkin-pkg distribute PyYAML
$ pip install nose coverage flake8 --upgrade
$ pip install mock
$ python setup.py nosetests -s

That mostly works, but some tests complain about not being able to find catkin. There's a few steps in the .travis.ymlI skipped.

[wjwwood]

Yeah, you'll need to install catkin and source the setup file for it.

[scpeters]

python3 failure: any advice?

  File "/home/travis/build/catkin/catkin_tools/catkin_tools/verbs/catkin_build/job.py", line 159, in get_multiarch
    assert(not out.strip() or out.strip().count('-') == 2)
TypeError: Type str doesn't support the buffer API

[wjwwood]

That error happens because the contents of out (I guess returned from calling out to the system) is a "bytes" array which is different from a str in Python3. You can decode out before you start doing normal operations on it if you like. Something like this:

>>> import subprocess
>>> out = subprocess.check_output('ls')
>>> out
b'foo\nbar'
>>> out.count('-')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Type str doesn't support the buffer API
>>> out = out.decode()
>>> out
'foo\nbar'
>>> out.count('-')
1

[scpeters]

I don't need to declare an explicit type for decode?

[scpeters]

I did that in 3833087 after seeing stack overflow

[wjwwood]

It defaults to utf-8.

[scpeters]

I'll squash after code review unless otherwise directed.

[wjwwood]

These calls to subprocess.Popen can raise a OSError or a FileNotFoundError if the executable you gave does not exist. You may need to catch that. You can test it by changing gcc to gcc_does_not_exist or something like that.

[wjwwood]

It would be good to either check that the executable exists before calling the subprocess or by catching these types of errors to be more graceful when there is an error.

[scpeters]

Confirmed that these raise errors. Will fix when I have a chance.

[scpeters]

I wrapped both Popen calls in try/except blocks. How does it look now?

[wjwwood]

+1 other than comments.

[wjwwood]

nitpick: Can you either make this return '' or update the above return '' to also be return ""?

[wjwwood]

+1 After the two nitpicks, I'll merge.

[wjwwood]

At first I was gonna let this pass, but it is bothering me...

It's not good practice to catch and silently pass on all exceptions. I know it's more work, but it would be better if you caught specific errors, something like this: except (OSError, FileNotFoundError):

[scpeters]

I fixed the last three comments and then squashed

[wjwwood]

Lgtm, I want to fixup something else, but I'll do that after the merge.

[wjwwood]

Never mind, I was thinking FileNotFoundError wasn't available before Python 3.3, but it is in Python 2.7 apparently too.

[scpeters]

Thanks for the review. I'll start recommending this to the gazebo developers once it is released.