ImportError after Pip update to v0.8.0

[Jaharmi]

I updated my virtualenv that includes blynclight to v0.8.0 using Pip. Afterwards, I get an import error both in ptpython and the same thing when using the CLI tool.

>>> from blynclight import BlyncLight                                           
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "$HOME/python-virtual-environments/rgb_led_status/lib/python3.8/site-packages/blynclight/__init__.py", line 34, in <module>
    from .blynclight import BlyncLight
  File "$HOME/python-virtual-environments/rgb_led_status/lib/python3.8/site-packages/blynclight/blynclight.py", line 4, in <module>
    import hid
  File "$HOME/python-virtual-environments/rgb_led_status/lib/python3.8/site-packages/hid/__init__.py", line 30, in <module>
    raise ImportError(error)
ImportError: Unable to load any of the following libraries:libhidapi-hidraw.so libhidapi-hidraw.so.0 libhidapi-libusb.so libhidapi-libusb.so.0 libhidapi-iohidmanager.so libhidapi-iohidmanager.so.0 libhidapi.dylib hidapi.dll libhidapi-0.dll

I'm looking into what's going on.

My update went from:

• blynclight-0.5.1 to blynclight-0.8.0
• not sure if hidapi was installed to hidapi-0.9.0.post3

[JnyJny]

So this is a replay of the previous issue (#17) but now the players are hidapi and Cython rather than my buggy HID wrapper and ctypes. Cython uses a hybrid language that's a combination of Python and C to wrap shared objects and I will have to do some research to find out how it locates shared libraries. The early workaround from #17 (copying files from /opt/local/lib to /usr/local/lib) will likely work in this case too. After research below this is not true.

I'll update as soon as I have a better idea of how Cython works.

[JnyJny]

I did some reading (docs and code) and have improved my understanding of Cython projects and packaging. It appears that cython-hidapi does not need a separate shared object installed to function. I tested this by removing hidapi and installing blycnlight in a virtual environment:

$ brew uninstall hidapi   # sudo port uninstall hidapi should work too
$ mkdir tmp; cd tmp
$ python3 -n venv venv 
$ source venv/bin/activate
$ pip install blynclight
...
$ blync # light turns on green

To be honest this is a tidier solution than my previous implementation, so I really hope we can get this working for you.

[JnyJny]

I'm curious what the output of pip list in that virtual environment with the busted blynclight installed.

In the venv created above, I got this output:

$ pip list
Package    Version
---------- -----------
blynclight 0.8.0
certifi    2020.6.20
chardet    3.0.4
click      7.1.2
hidapi     0.9.0.post3
idna       2.9
pip        20.1.1
requests   2.24.0
setuptools 47.3.1
typer      0.2.1
urllib3    1.25.9

[JnyJny]

Embarrassingly, the 0.8.0 release was built from a feature branch (hid) and not master which may or may not have been completely up-to-date. I've reconciled the two branches and pushed a new release 0.8.2 to PyPI.

[Jaharmi]

I got both the blynclight and luxafaret modules — or at least their CLI tools — to work with the following new venv. I installed only the two "busy light" modules and their requirements, along with updating pip. It looks like Pip installed the new release v0.8.2.

$ pip list
Package    Version
---------- -------------
blynclight 0.8.2
certifi    2020.6.20
chardet    3.0.4
click      7.1.2
hidapi     0.7.99.post21
idna       2.9
luxafaret  1.1.0
pip        20.1.1
requests   2.24.0
setuptools 41.2.0
typer      0.2.1
urllib3    1.25.9
webcolors  1.11.1

There is a conflict between the two "busy light" modules I'm currently using when it comes to hidapi but both appear to work fine with the older version required by luxafaret.

ERROR: blynclight 0.8.2 has requirement hidapi<0.10.0,>=0.9.0, but you'll have hidapi 0.7.99.post21 which is incompatible.

I made no other changes to the compiled libraries installed in my /usr/local/lib and /opt/local/lib directories.

Meanwhile, my errors were in a different venv that contained the following modules. I'd been experimenting with different modules to control my two RGB LED busy lights.

$ pip list
Package        Version
-------------- -------------
appdirs        1.4.4
blynclight     0.8.0
certifi        2020.4.5.2
chardet        3.0.4
click          7.1.2
Flask          1.1.2
Flask-HTTPAuth 4.1.0
gevent         20.6.2
greenlet       0.4.16
hid            1.0.4
hidapi         0.7.99.post21
idna           2.9
itsdangerous   1.1.0
jedi           0.17.0
Jinja2         2.11.2
luxafaret      1.1.0
MarkupSafe     1.1.1
parso          0.7.0
pip            20.1.1
prompt-toolkit 3.0.5
ptpython       3.0.2
Pygments       2.6.1
pyluxa4        1.6
requests       2.23.0
setuptools     41.2.0
typer          0.2.1
urllib3        1.25.9
wcwidth        0.2.4
webcolors      1.11.1
Werkzeug       1.0.1
wheel          0.34.2
zope.event     4.4
zope.interface 5.1.0

[JnyJny]

I think I see a problem in the pip list output: there is a hid and hidapi listed and they both likely provide a 'hid' namespace. I'll have to check, but my gut says that blynclight was expecting to get hidapi's namespace and got the other (which blew up for unrelated reasons. I spent a lot of time trying to figure out where that error message was either in my code or in the trezor/cython-hidapi code).

I can relax the version requirements for hidapi in the packaging for blynclight to see if that helps improve your situation.

[JnyJny]

Yep, I've recreated the error that started this issue. I don't have libhidapi.dyld installed by either ports or brew:

$ pip list
Package    Version
---------- ---------
certifi    2020.6.20
chardet    3.0.4
click      7.1.2
hid        1.0.4
idna       2.9
pip        20.1.1
requests   2.24.0
setuptools 47.3.1
typer      0.2.1
urllib3    1.25.9

$ python3 -c "import hid"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/ejo/tmp/venv/.venv/lib/python3.7/site-packages/hid/__init__.py", line 30, in <module>
    raise ImportError(error)
ImportError: Unable to load any of the following libraries:libhidapi-hidraw.so libhidapi-hidraw.so.0 libhidapi-libusb.so libhidapi-libusb.so.0 libhidapi-iohidmanager.so libhidapi-iohidmanager.so.0 libhidapi.dylib hidapi.dll libhidapi-0.dll

It is my opinion that the Cython hidapi solution is superior by nearly every measure I can think of:

• tracks libhidapi closely
• pip install builds a shared object directly used by python
• does not require the user to install hidapi via [brew|port|apt-get|yum|rpm|whatever]
• actively developed (by not me)

If you like, I can take a look at the luxafaret code to see about porting to Cython hidapi ( should be trivial ).

[JnyJny]

So I took a look at the Luxafaret project and it seems a little abandoned. I've ordered a LuxaFor flag and it should be here Thursday :) I'll add support to blynclight for the Flag and that will solve having to get our two projects synced enough to not interfere with each other.

[JnyJny]

@Jaharmi I've got a new project you might be interested in, busylight-for-humans. It supports both Embrava BlyncLights and Luxafor Flags from the same command-line:

$ busylight list
...
$ busylight supported
Embrava BlyncLight
Luxafor Flag
$ busylight on
$ busylight blink
$ busylight off

This should help you work with your lights while not having to fight dependencies. Let me know how it works for you.