WfEpy¶
WfEpy (Workflow Engine for Python) is Python library for creating workflows and automating various processes. It is designed to be as simple as possible so developers can focus on tasks logic, not how to execute workflow, store state, etc.
Individual steps in workflow are simply functions with decorator and transitions between tasks are also defined by decorators. Everything what developer needs to do is add few decorators to functions that implements tasks logic. This library is then used to build graph from tasks and transitions and execute tasks in workflow by traversing graph and calling task functions. Context passed to each function is arbitrary user object that can be used to store data, connect to other services or APIs, …
@wfepy.task()
@wfepy.start_point()
@wfepy.followed_by('make_coffee')
def start(context):
...
@wfepy.task()
@wfepy.followed_by('drink_coffee')
def make_coffee(context):
...
@wfepy.task()
@wfepy.followed_by('end')
def drink_coffee(context):
...
@wfepy.task()
@wfepy.end_point()
def end(context):
...
WfEpy does not provide any server scheduler or something like that. It was designed to be used in scripts, that are for example periodically executed by cron. If workflow have task that cannot be finished in single run library provides way how to store current state of runner including user data and restore it on next run.
import coffee_workflow
wf = wfepy.Workflow()
wf.load_tasks(coffee_workflow)
runner = wf.create_runner()
if restore_state:
runner.load('state-file')
runner.run()
runner.dump('state-file')
This simple design provides many options how to execute your workflow and customize it. This was also reason why this library was created, we don’t want to manage new service/server that executes few simple workflows. We would like to use service we already have, for example Jenkins, cron, …
Installation¶
Install it using pip
pip3 install wfepy
or clone repository
git clone https://github.com/redhat-aqe/wfepy.git
cd wfepy
and install Python package including dependencies
python3 setup.py install