Debug Qt Signals with graph

debug_qtsignals_with_graph.py

import functools
import inspect

import graphviz
from PyQt4 import QtCore
from PyQt4 import QtGui


class MyGraph(object):
    def __init__(self):
        self.dot = graphviz.Digraph()

    def add_node(self, sender, signal, slot):
        self.dot.edge(sender, signal)
        self.dot.edge(signal, slot)

    def render(self):
        self.dot.render('test.png', view=True)


my_graph = MyGraph()


def log_manual_slot(f):
    """
    Decorate functions that are passed to the signal 'connect' method.
    
    Example:
        >>> mysignal.connect(log_manual_slot(myslot))
    """
    @functools.wrap(f)
    def wrapper(*args, **kwargs):
        signal_name = inspect.stack()[1][0].f_code.co_names[-2]
        sender = str(inspect.stack()[1][3])
        logger.debug('{0}{1} emitted by {2} and picked up by {3}'.format(
            signal_name,
            args,
            sender,
            f.__name__)
        my_graph.add_node(sender, signal_name, f.__name__)
        return f(*args)
    return wrapper
    
    
def log_automatic_slot(f):
    """ Decorate 'pyqtSlot' decorated methods. """
    @functools.wrap(f)
    def wrapper(*args, **kwargs):
        _, signal_name = f.__name__.rsplit('_', 1)
        sender = str(args[0].sender())
        logger.debug('{0}{1} emitted by {2} and picked up by {3}'.format(
            signal_name,
            args[1:],
            sender,
            f.__name__)
        my_graph.add_node(sender, signal_name, f.__name__)
        return f(*args)
    return wrapper


class MainWindow(QtGui.QMainWindow):

    updated = QtCore.pyqtSignal(str)

    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.button = QtGui.QPushButton('My button', self)
        self.button.setObjectName('mybutton')

        QtCore.QMetaObject.connectSlotsByName(self)

    @log_automatic_slot
    @QtCore.pyqtSlot()
    def on_mybutton_clicked(self):
        self.updated.emit('hello, world!')


def update_recv(data):
    1 + 1


def update_recv2(data):
    1 + 1


if __name__ == '__main__':
    import sys

    app = QtGui.QApplication([])

    view = MainWindow()
    view.updated.connect(log_manual_slot(update_recv))
    view.updated.connect(log_manual_slot(update_recv2))
    view.show()

    app.exec_()

    my_graph.render()