Pyeventbus: a publish/subscribe event bus

Last update: Apr 21, 2022

Overview

pyeventbus

pyeventbus is a publish/subscribe event bus for Python 2.7.

simplifies the communication between python classes
decouples event senders and receivers
performs well threads, greenlets, queues and concurrent processes
avoids complex and error-prone dependencies and life cycle issues
makes code simpler
has advanced features like delivery threads, workers and spawning different processes, etc.
is tiny (3KB archive)

pyeventbus in 3 steps:

Define events:

class MessageEvent:
    # Additional fields and methods if needed
    def __init__(self):
        pass

Prepare subscribers: Declare and annotate your subscribing method, optionally specify a thread mode:

from pyeventbus import *

@subscribe(onEvent=MessageEvent)
def func(self, event):
    # Do something
    pass

from pyeventbus import *

class MyClass:
    def __init__(self):
        pass

    def register(self, myclass):
        PyBus.Instance().register(myclass, self.__class__.__name__)

# then during initilization

myclass = MyClass()
myclass.register(myclass)

Post events:

from pyeventbus import *

class MyClass:
    def __init__(self):
        pass

    def register(self, myclass):
        PyBus.Instance().register(myclass, self.__class__.__name__)

    def postingAnEvent(self):
        PyBus.Instance().post(MessageEvent())

 myclass = MyClass()
 myclass.register(myclass)
 myclass.postingAnEvent()

Modes: pyeventbus can run the subscribing methods in 5 different modes

POSTING:

Runs the method in the same thread as posted. For example, if an event is posted from main thread, the subscribing method also runs in the main thread. If an event is posted in a seperate thread, the subscribing method runs in the same seperate method

This is the default mode, if no mode has been provided::

@subscribe(threadMode = Mode.POSTING, onEvent=MessageEvent)
def func(self, event):
    # Do something
    pass

PARALLEL:

Runs the method in a seperate python thread::

@subscribe(threadMode = Mode.PARALLEL, onEvent=MessageEvent)
def func(self, event):
    # Do something
    pass

GREENLET:

Runs the method in a greenlet using gevent library::

@subscribe(threadMode = Mode.GREENLET, onEvent=MessageEvent)
def func(self, event):
    # Do something
    pass

BACKGROUND:

Adds the subscribing methods to a queue which is executed by workers::

@subscribe(threadMode = Mode.BACKGROUND, onEvent=MessageEvent)
def func(self, event):
    # Do something
    pass

CONCURRENT:

Runs the method in a seperate python process::

@subscribe(threadMode = Mode.CONCURRENT, onEvent=MessageEvent)
def func(self, event):
    # Do something
    pass

Adding pyeventbus to your project:

pip install pyeventbus

Example:

git clone https://github.com/n89nanda/pyeventbus.git

cd pyeventbus

virtualenv venv

source venv/bin/activate

pip install pyeventbus

python example.py

Benchmarks and Performance:

Refer /pyeventbus/tests/benchmarks.txt for performance benchmarks on CPU, I/O and networks heavy tasks.

Run /pyeventbus/tests/test.sh to generate the same benchmarks.

Performance comparison between all the modes with Python and Cython

Inspiration

Inspired by Eventbus from greenrobot: https://github.com/greenrobot/EventBus

You might also like...

Code for the paper "Unsupervised Contrastive Learning of Sound Event Representations", ICASSP 2021.

Unsupervised Contrastive Learning of Sound Event Representations This repository contains the code for the following paper. If you use this code or pa

81 Dec 22, 2022

Repo for "Event-Stream Representation for Human Gaits Identification Using Deep Neural Networks"

Summary This is the code for the paper Event-Stream Representation for Human Gaits Identification Using Deep Neural Networks by Yanxiang Wang, Xian Zh

54 Jan 3, 2023

Cross-media Structured Common Space for Multimedia Event Extraction (ACL2020)

Cross-media Structured Common Space for Multimedia Event Extraction Table of Contents Overview Requirements Data Quickstart Citation Overview The code

49 Nov 21, 2022

CVPRW 2021: How to calibrate your event camera

E2Calib: How to Calibrate Your Event Camera This repository contains code that implements video reconstruction from event data for calibration as desc

104 Nov 16, 2022

Repository relating to the CVPR21 paper TimeLens: Event-based Video Frame Interpolation

TimeLens: Event-based Video Frame Interpolation This repository is about the High Speed Event and RGB (HS-ERGB) dataset, used in the 2021 CVPR paper T

544 Dec 19, 2022

An implementation for `Text2Event: Controllable Sequence-to-Structure Generation for End-to-end Event Extraction`

Text2Event An implementation for Text2Event: Controllable Sequence-to-Structure Generation for End-to-end Event Extraction Please contact Yaojie Lu (@

153 Jan 7, 2023

Official PyTorch implementation of N-ImageNet: Towards Robust, Fine-Grained Object Recognition with Event Cameras (ICCV 2021)

N-ImageNet: Towards Robust, Fine-Grained Object Recognition with Event Cameras Official PyTorch implementation of N-ImageNet: Towards Robust, Fine-Gra

32 Dec 26, 2022

SurvITE: Learning Heterogeneous Treatment Effects from Time-to-Event Data

SurvITE: Learning Heterogeneous Treatment Effects from Time-to-Event Data SurvITE: Learning Heterogeneous Treatment Effects from Time-to-Event Data Au

14 Nov 28, 2022

Weakly Supervised Dense Event Captioning in Videos, i.e. generating multiple sentence descriptions for a video in a weakly-supervised manner.

WSDEC This is the official repo for our NeurIPS paper Weakly Supervised Dense Event Captioning in Videos. Description Repo directories ./: global conf

96 Nov 1, 2022

Comments

Same method name for multiple subscribers bug

Please see the code below. To summarize:

Define one event
Define two subscriber listening for the event above. Each subscriber has a listener method with the name on_event
Each of the subscriber classes above defines an instance field, but with unique name (self.something in the first class, self.something2 in the second class)
Define another class that posts an event

Run this scenario and get the error below:

Exception in thread thread-on_event:
Traceback (most recent call last):
  File "C:\Anaconda2\envs\python\lib\threading.py", line 801, in __bootstrap_inner
    self.run()
  File "C:\Anaconda2\envs\python\lib\site-packages\pyeventbus\pyeventbus.py", line 112, in run
    self.method(self.subscriber, self.event)
  File "C:/FractureID/projects/python/ui/spectraqc/PyEventBusBug.py", line 16, in on_event
    print (self.something)
AttributeError: Subscriber2 instance has no attribute 'something'

Exception in thread thread-on_event:
Traceback (most recent call last):
  File "C:\Anaconda2\envs\python\lib\threading.py", line 801, in __bootstrap_inner
    self.run()
  File "C:\Anaconda2\envs\python\lib\site-packages\pyeventbus\pyeventbus.py", line 112, in run
    self.method(self.subscriber, self.event)
  File "C:/FractureID/projects/python/ui/spectraqc/PyEventBusBug.py", line 26, in on_event
    print (self.something_else)
AttributeError: Subscriber1 instance has no attribute 'something_else'

It complains about the variable in class two not having the attribute in the first class and the other way around.

If I change on of the on_event to something else like on_event2 then the issue is gone.

from pyeventbus import *


class SomeEvent:
    def __init__(self):
        pass


class Subscriber1:
    def __init__(self):
        self.something = 'First subscriber'
        PyBus.Instance().register(self, self.__class__.__name__)

    @subscribe(threadMode=Mode.PARALLEL, onEvent=SomeEvent)
    def on_event(self, event):
        print (self.something)


class Subscriber2:
    def __init__(self):
        self.something_else = 'Second subscriber'
        PyBus.Instance().register(self, self.__class__.__name__)

    @subscribe(threadMode=Mode.PARALLEL, onEvent=SomeEvent)
    def on_event(self, event):
        print (self.something_else)


class PyEventBusBug:

    def __init__(self):
        Subscriber1()
        Subscriber2()
        PyBus.Instance().post(SomeEvent())


if __name__ == "__main__":
    PyEventBusBug()

bug

opened by ddanny 0

Doesn't even start on Windows because 2000 threads is apparently too much

  File "C:\Python27\lib\site-packages\pyeventbus\pyeventbus.py", line 116, in subscribe
    bus = PyBus.Instance()
  File "C:\Python27\lib\site-packages\pyeventbus\Singleton.py", line 30, in Instance
    self._instance = self._decorated()
  File "C:\Python27\lib\site-packages\pyeventbus\pyeventbus.py", line 24, in __init__
    for worker in [lambda: self.startWorkers() for i in range(self.num_threads)]: worker()
  File "C:\Python27\lib\site-packages\pyeventbus\pyeventbus.py", line 24, in <lambda>
    for worker in [lambda: self.startWorkers() for i in range(self.num_threads)]: worker()
  File "C:\Python27\lib\site-packages\pyeventbus\pyeventbus.py", line 30, in startWorkers
    worker.start()
  File "C:\Python27\lib\threading.py", line 736, in start
    _start_new_thread(self.__bootstrap, ())
thread.error: can't start new thread

See also: https://stackoverflow.com/a/1835043/2583080

bug

opened by PawelTroka 4

Releases(0.2)

0.2(Feb 2, 2018)

added performance benchmarks and tests
Source code(tar.gz)
Source code(zip)
0.1(Feb 2, 2018)

first stable release
Source code(tar.gz)
Source code(zip)

Owner

GitHub Repository

Automatic Idiomatic Expression Detection

IDentifier of Idiomatic Expressions via Semantic Compatibility (DISC) An Idiomatic identifier that detects the presence and span of idiomatic expressi

5 Jun 09, 2022

Official implementation of SynthTIGER (Synthetic Text Image GEneratoR) ICDAR 2021

🐯 SynthTIGER: Synthetic Text Image GEneratoR Official implementation of SynthTIGER | Paper | Datasets Moonbin Yim1, Yoonsik Kim1, Han-cheol Cho1, Sun

256 Jan 05, 2023

TensorFlow implementation of "A Simple Baseline for Bayesian Uncertainty in Deep Learning"

7 Aug 28, 2022

Locally Enhanced Self-Attention: Rethinking Self-Attention as Local and Context Terms

LESA Introduction This repository contains the official implementation of Locally Enhanced Self-Attention: Rethinking Self-Attention as Local and Cont

20 Dec 31, 2021

Official DGL implementation of "Rethinking High-order Graph Convolutional Networks"

SE Aggregation This is the implementation for Rethinking High-order Graph Convolutional Networks. Here we show the codes for citation networks as an e

32 Jul 19, 2022

Files for a tutorial to train SegNet for road scenes using the CamVid dataset

SegNet and Bayesian SegNet Tutorial This repository contains all the files for you to complete the 'Getting Started with SegNet' and the 'Bayesian Seg

800 Dec 31, 2022

This code uses generative adversarial networks to generate diverse task allocation plans for Multi-agent teams.

Mutli-agent task allocation This code uses generative adversarial networks to generate diverse task allocation plans for Multi-agent teams. To change

5 Oct 12, 2022

Conservative and Adaptive Penalty for Model-Based Safe Reinforcement Learning

Conservative and Adaptive Penalty for Model-Based Safe Reinforcement Learning This is the official repository for Conservative and Adaptive Penalty fo

7 Nov 22, 2022

Contrastive Language-Image Pretraining

CLIP [Blog] [Paper] [Model Card] [Colab] CLIP (Contrastive Language-Image Pre-Training) is a neural network trained on a variety of (image, text) pair

11.5k Jan 08, 2023

Code for CVPR 2018 paper --- Texture Mapping for 3D Reconstruction with RGB-D Sensor

G2LTex This repository contains the implementation of "Texture Mapping for 3D Reconstruction with RGB-D Sensor (CVPR2018)" based on mvs-texturing. Due

129 Dec 30, 2022

A Research-oriented Federated Learning Library and Benchmark Platform for Graph Neural Networks. Accepted to ICLR'2021 - DPML and MLSys'21 - GNNSys workshops.

FedGraphNN: A Federated Learning System and Benchmark for Graph Neural Networks A Research-oriented Federated Learning Library and Benchmark Platform

175 Dec 01, 2022

MAg: a simple learning-based patient-level aggregation method for detecting microsatellite instability from whole-slide images

MAg Paper Abstract File structure Dataset prepare Data description How to use MAg? Why not try the MAg_lib! Trained models Experiment and results Some

3 Apr 08, 2022