Invoking Pylint programmatically

I'd like to invoke the Pylint checker, limited to the error signalling part, as part of my unit testing. So I checked the Pylint executable script, got to the pylint.lint.Run helper class and there I got lost in a quite long __init__ function, ending with a call to sys.exit().

Anybody ever tried and managed to do so?

The dream-plan would be this:

if __name__ == '__main__':
  import pylint.lint
  pylint.lint.something(__file__, justerrors=True)
  # now continue with unit testing

Any hints? Other than "copy the __init__ method and skip the sys.exit()", I mean?

I don't need the tests to be run by Pylint, it might as well be pyflakes or other software: feel free to suggest alternatives.

Take a look at the pylint/epylint.py file which contains two different ways to start Pylint programmatically.

You can also simply call

from pylint.lint import Run
Run(['--errors-only', 'myfile.py'])

for instance.

I got the same problem recently. syt is right, pylint.epylint got several methods in there. However they all call a subprocess in which python is launched again. In my case, this was getting quite slow.

Building from mcarans answer, and finding that there is a flag exit, I did the following

class WritableObject(object):
    "dummy output stream for pylint"
    def __init__(self):
        self.content = []
    def write(self, st):
        "dummy write"
        self.content.append(st)
    def read(self):
        "dummy read"
        return self.content
def run_pylint(filename):
    "run pylint on the given file"
    from pylint import lint
    from pylint.reporters.text import TextReporter
    ARGS = ["-r","n", "--rcfile=rcpylint"]  # put your own here
    pylint_output = WritableObject()
    lint.Run([filename]+ARGS, reporter=TextReporter(pylint_output), exit=False)
    for l in pylint_output.read():
        do what ever you want with l...

which is about 3 times faster in my case. With this I have been going through a whole project, using full output to check each source file, point errors, and rank all files from their note.