stefuna 0.8.1

AWS Step Function Activity server framework

.. image:: https://travis-ci.org/irothschild/stefuna.svg
:target: https://travis-ci.org/irothschild/stefuna

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stefuna
===============================

Stefuna is a simple AWS Step Function Activity server framework.
It makes it incredibly quick and easy to write workers to
process activity tasks in Python.

Implementation
---------------

Stefuna uses a multiprocessing Pool of pre-forked worker processes
to run the activity tasks. The is a single instance of a Worker
class in each worker process. To implement your task, simply
create a Worker subclass, override the
``run_task(self, task_token, input_data)`` method and start the
server.

The ``run_task`` method can do whatever work it requires and then
return a result as a string or dict (which is automatically JSON
stringified). If the method raises an exception, the task is failed
with a ``Task.Failure`` error.

Configurable heartbeats are supported for longer-running tasks.


Getting Started
---------------

See the examples folder for the files described below.

Create a worker class, which is a subclass of the `stefuna.Worker`
in the file `hello_worker.py`:

.. code-block:: python
import logging
from stefuna import Worker

logger = logging.getLogger('stefuna.example')


class HelloWorker(Worker):

def init(self):
"""Initialize the single instance in a worker"""
pass

def run_task(self, task_token, input_data):
self.logger.debug('Worker in run_task')

# Do some work!

# Return value can be a string or a dict/array that
# will be JSON stringified.
return {"message": "Hello World"}


Create a config file `hello_config.py`, setting the worker class, server name, and
activity ARN:

.. code-block:: python
#
# Stefuna server worker config file
#

# The module path of the worker class
worker = 'examples.hello_worker.HelloWorker'

# The base name of the server that will be combined with host and pid
# and used when requesting tasks from AWS.
name = 'HelloExample'

# Set the ARN for the activity that this server will work on.
activity_arn = 'arn:aws:states:us-west-2:00000000000000:activity:hello'

# The number of worker processes.
# If None, it will be set to the number of cores.
processes = None

# Maximum number of seconds between heartbeats.
# None or 0 means there is no heartbeat.
heartbeat = 120

# Maximum number of tasks for a worker to run before the worker
# process is automatically killed and a new one created.
# If None, workers will not be killed.
maxtasksperchild = None

# The worker_config is an arbitrary dictionary that is available
# in the worker instance as self.config
# Use it for worker-specific configuration.
worker_config = {
'foo': 'bar'
}


Run the server:

.. code-block:: bash
$ stefuna --config=hello_config


History (Change Log)
--------------------

See `HISTORY.rst <HISTORY.rst>`_


License
-------

MIT License

See `LICENSE <LICENSE>`_




History
-------

0.8.1 [2017-08-15]
* First public release