processor 0.10.0
A microframework to build source -> filter -> action workflows.
License: BSD
Keywords: processing,devops,imap,rss,twitter

================
python-processor
================

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Simple rules
==============

Python processor is a tool for creating chained pipelines for dataprocessing.
It have very few key concepts:

Data object
    Any python dict with two required fields: ``source`` and ``type``.
Source
    An iterable sequence of ``data objects`` or a function which returns ``data objects``.
    See `full list of sources`_ in the docs.
Output
    A function which accepts a ``data object`` as input and could output another. See `full list of outputs`_ in the docs.
    (or same) ``data object`` as result.
Predicate
    Pipeline consists from sources outputs, but ``predicate`` decides which
    ``data object`` should be processed by which ``output``.

Quick example
=============

Here is example of pipeline which reads IMAP folder and sends all emails to Slack chat:

.. code:: python

    run_pipeline(
        sources.imap('imap.gmail.com'
                     'username',
                     'password'
                     'INBOX'),
        [prepare_email_for_slack, outputs.slack(SLACK_URL)])

Here you construct a pipeline, which uses ``sources.imap`` for reading imap folder
"INBOX" of ``username@gmail.com``. In more complex case ``outputs.fanout``
can be used for routing dataobjects to different processors and ``sources.mix`` can
be used to merge items two or more sources into a one stream.

Functions ``prepare_email_to_slack`` and ``outputs.slack(SLACK_URL)`` are processors. First one
is a simple function which accepts data object, returned by imap source and transforming
it to the data object which could be used by slack.output. We need that because slack
requires a different set of fields. Call to ``outputs.slack(SLACK_URL)`` returns a
function which gets an object and send it to the specified Slack's endpoint.

It is just example, for working snippets, continue reading this documention ;-)

.. Note:: By the way, did you know there is a Lisp dialect which runs on Python
          virtual machine? It's name is HyLang, and python processor is written in this
          language.

    
Installation
============

Create a virtual environment with python3:::
  
   virtualenv --python=python3 env
   source env/bin/activate

Install required version of hylang (this step is necessary because Hy syntax is not
final yet and frequently changed by language maintainers):::

  pip install -U 'git+git://github.com/hylang/hy.git@a3bd90390cb37b46ae33ce3a73ee84a0feacce7d#egg=hy'

If you are on OSX, then install lxml on OSX separately:::
   
   STATIC_DEPS=true pip install lxml

If you want to access IMAP over SSL on OSX, then you need to install
``openssl`` via homebrew, and then install ``pyopenssl`` like this:::

  brew install openssl
  env LDFLAGS="-L$(brew --prefix openssl)/lib" \
      CFLAGS="-I$(brew --prefix openssl)/include" \
      pip install -U --force-reinstall pyopenssl

Then install the ``processor``:::

    pip install processor

Usage
=====

Now create an executable python script, where you'll place your pipline's configuration.
For example, this simple code creates a process line which searches new results in Twitter
and outputs them to console. Of cause, you can output them not only to console, but also
post by email, to Slack chat or everywhere else if there is an output for it:

.. code:: python

    #!env/bin/python3
    import os
    from processor import run_pipeline, sources, outputs
    from twiggy_goodies.setup import setup_logging


    for_any_message = lambda msg: True

    def prepare(tweet):
        return {'text': tweet['text'],
                'from': tweet['user']['screen_name']}

    setup_logging('twitter.log')

    run_pipeline(
        sources=[sources.twitter.search(
            'My Company',
            consumer_key='***', consumer_secret='***',
            access_token='***', access_secret='***',
            )],
        rules=[(for_any_message, [prepare, outputs.debug()])])


Running this code, will fetch new results for search by query ``My Company``
and output them on the screen. Of course, you could use any other ``output``,
supported by the ``processor``. Browse online documentation to find out
which sources and outputs are supported and for to configure them.


.. _full list of sources: sources.html
.. _full list of outputs: outputs.html


Ideas for Sources and Outputs
=============================

* ``web-hook`` endpoint `(in progress)`.
* ``tail`` source which reads file and outputs lines appeared in a file between invocations
  or is able to emulate ``tail -f`` behaviour. Python module
  `tailer <https://pypi.python.org/pypi/tailer/>`_ could be used here.
* ``grep`` output -- a filter to grep some fields using patterns. With ``tail`` and ``grep``
  you could build a pipeline which watch on a log and send errors by email or to the chat.
* ``xmpp`` output.
* ``irc`` output.
* ``rss/atom feed reader``.
* ``weather`` source which tracks tomorrow's weather forecast and outputs a message if it was
  changed significantly, for example from "sunny" to "rainy".
* ``github`` some integrations with github API?
* ``jira`` or other task tracker of your choice?
* `suggest your ideas!`


Documentation
=============

https://python-processor.readthedocs.org/


Development
===========

To run the all tests run::

    tox


Authors
=======

* Alexander Artemenko - http://dev.svetlyak.ru

Changelog
=========

0.10.0 (2016-01-04)
-------------------

* IMAP source was fixed to work with new IMAPClient's API and
  support ``IMAPClient > 1.0.0``.
* Datastorage was fixed to get ``filename`` from ``PROCESSOR_DB``
  environment variable in case if it was setup using
  ``os.environ['PROCESSOR_DB'] = 'some.db'`` after the imports.

0.9.0 (2015-12-06)
------------------

Code was fixed to work with HyLang from ``a3bd90390cb37b46ae33ce3a73ee84a0feacce7d``
commit. Please, use this pinned version of HyLang and `subscribe`_ on future
release notes to know when this requirement will change.

.. _subscribe: https://allmychanges.com/p/python/processor/

0.8.0 (2015-11-16)
------------------

* Code was fixed to work with latest Hy, from GitHub.
* Added ``twitter.mentions`` source, to read stream of mentions from the Twitter.
* Fixed a way how number of messages from IMAP folder is limited. Previously
  limit was applied even when we already know an ID of the last seen message,
  but now limit is ignored in this case and only applied when visiting the
  folder first time.

0.7.0 (2015-05-05)
------------------

New output – XMPP was added and now processor is able
to notify Jabber users.

0.6.0 (2015-05-01)
------------------

The biggest change in this release is a new source – ``github.releases``.
It is able to read all new releases in given repository and send them into
processing pipeline. This works as for public repositories, and for private
too. `Read the docs`_ for futher details.

.. _Read the docs: https://python-processor.readthedocs.org/en/latest/sources.html#github-releases

Other changes are:

* Storage backend now saves JSON database nicely pretty printed for you could read and edit it in your favorite editor. This is Emacs, right?
* Twitter.search source now saves state after the tweet was processed. This way processor shouldn't loose tweets if there was exception somewhere in processing pipeline.
* IMAP source was fixed and now is able to fetch emails from really big folders.


0.5.0 (2015-04-15)
------------------

Good news, everyone! New output was added - ``email``.
Now Processor is able to notify you via email about any event.

0.4.0 (2015-04-06)
------------------

* Function ``run_pipline`` was simplified and now accepts only one source and one ouput.
  To implement more complex pipelines, use ``sources.mix`` and ``outputs.fanout`` helpers.

0.3.0 (2015-04-01)
------------------

* Added a `web.hook`_ source.
* Now `source` could be not only a iterable object, but any function which returns values.

.. _web.hook: https://python-processor.readthedocs.org/en/latest/sources.html#web-hook

0.2.1 (2015-03-30)
------------------

Fixed error in ``import-or-error`` macro, which prevented from using 3-party libraries.

0.2.0 (2015-03-30)
------------------

Most 3-party libraries are optional now. If you want to use
some extension which requires external library, it will issue
an error and call ``sys.exit(1)`` until you satisfy this
requirement.

This should make life easier for thouse, who does not want
to use ``rss`` output which requires ``feedgen`` which requires
``lxml`` which is hard to build because it is C extension.

0.1.0 (2015-03-18)
------------------

* First release on PyPI.