joshuakwan / hystrix-py

Latency and fault tolerance for distributed systems

hystrix-py

A Netflix Hystrix port to Python.

This is a work in progress, please feel free to help!

What is Hystrix?

For more information see the [Netflix Hystrix] (https://github.com/Netflix/Hystrix/wiki) Wiki documentation.

How it works

To know more see the [Netflix Hystrix] (https://github.com/Netflix/Hystrix/wiki/How-it-Works) Wiki How it works section documentation.

Features

It's ALPHA version and only support launching a group of commands inside an executor pool.

• Execute synchronous commands.
• Execute asynchronous commands.
• Execute asynchronous commands and attach a callback.

Requirements

It depends on [concurrent.futures] (https://docs.python.org/3/library/concurrent.futures.html), new in Python version 3.2 and [enum] (https://docs.python.org/3.4/library/enum.html), new in Python version 3.4. It uses futures and enum34 backports to run in Python version 2.7, 3.3 and 3.4.

Installation

Create a virtualenv:

mkproject --python=<fullpath_to_python_3.2+> hystrix-py

Get the code:

git clone https://github.com/wiliamsouza/hystrix-py .

Install it:

python setup.py develop

The last command enter your code in "Development Mode" it creates an egg-link in your virtualenv's site-packages making it available on this environment sys.path. For more info see [setuptools development-mode] (https://pythonhosted.org/setuptools/setuptools.html#development-mode)

Development and test dependencies

setup.py will handle test dependencies, to install development use:

pip install -e .[dev]

Tests

python setup.py test

Hello world

Code to be isolated is wrapped inside the run() method of a hystrix.Command similar to the following:

from hystrix import Command

class HelloWorldCommand(Command):
    def run(self):
        return 'Hello World'

This command could be used like this:

command = HelloCommand()

# synchronously
print(command.execute())
'Hello World'

# asynchronously
future = command.queue()
print(future.result())
'Hello Wold'

# callback
def print_result(future)
     print(future.result())

future = command.observe()
future.add_done_callback(print_result)

LICENSE

Copyright 2015 Hystrix Python Authors.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.