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python-3.xtwistedklein-mvc

twistd -n web not working with Klein and Python3

i'm try to run twistd web with Klein and got a lot of issues. Even if try run it from an example - got the same results. Source 

from klein import Klein
app = Klein()

@app.route('/')
def hello(request):
    return "Hello, world!"

resource = app.resource

Then run it (in this example, the file above is saved as twistdPlugin.py:

$ twistd -n web --class=twistdPlugin.resource

Errors: sh-3.2# twistd -n web --class=twistdPlugin.resource Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/3.6/bin/twistd", line 11, in <module> load_entry_point('Twisted==17.9.0', 'console_scripts', 'twistd')() File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/scripts/twistd.py", line 29, in run app.run(runApp, ServerOptions) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/application/app.py", line 657, in run config.parseOptions() File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/application/app.py", line 624, in parseOptions usage.Options.parseOptions(self, options) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/python/usage.py", line 267, in parseOptions self.subOptions.parseOptions(rest) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/python/usage.py", line 255, in parseOptions self._dispatch[optMangled](optMangled, arg) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/python/usage.py", line 411, in <lambda> fn = lambda name, value, m=method: m(value) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/web/tap.py", line 121, in opt_class classObj = reflect.namedClass(className) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/python/reflect.py", line 173, in namedObject module = namedModule('.'.join(classSplit[:-1])) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/twisted/python/reflect.py", line 159, in namedModule topLevel = __import__(name) ModuleNotFoundError: No module named 'twistdPlugin'

How to be with this?

Solution

  • You can solve this 1 of 2 ways. First way would be to add the directory with your source code to the PYTHONPATH environment variable. This is the easiest method.

    PYTHONPATH=$(pwd) twistd -n web --class twistdPlugin.resource

    Or you could make a virtualenv and install your twistdPlugin module there. This way you won't have to mess with environment variables yourself.

    The tl;dr of the matter is that twistd used to source the current directory in Python 2 Twisted < 16.4 but it doesn't do that anymore with Python 3 the lastest Twisted. In other words, twistd expects all modules to be importable. Despite being a nuisance at times, this design makes twistd apps portable.