pyconverge

Resolve configurations from abstract hierarchies and templates

Project description

|GitHub tag| |GitHub release| |PyPI| |Py Versions|

|Build Status| |Coverage Status| |Quality Gate| |Code Smells| |File
Complexity| |Vulnerabilities| |Technical Dept| |Lines of code|

converge
========

*Resolve Data from Abstract Hierarchies and Templates*

Managing configuration is hard. More often than not you have high
key/values duplication and storage.
`DRY <https://en.wikipedia.org/wiki/Don't_repeat_yourself>`__ your
tears, it's time for some hierarchical magic, so you can get back to the
important stuff.

This is where **converge** comes in. There are a few basic concepts when
using or extend converge: \* Readers: get data from your backends \*
Filters: filter data before or after resolution (*example: search &
replace values, inject data post resolution*) \* Resolvers: convert
abstract data to resolved data \* Writers: output your data to the
format and backend you need

Abstract hierarchies of data chewed up and spit out to your liking.

Getting started
===============

install pyconverge, this will add the ``converge`` command to your
classpath using setup.py/PyPi

.. code:: bash

pip install pyconverge
converge version
converge --help

Create a converge.yaml.template file in your project working directory,
modify and move it to converge.yaml

.. code:: bash

# create the converge.yaml.template file
converge init conf
# modify your converge parameters
vim converge.yaml.template
# activate converge
mv converge.yaml.template converge.yaml
# verify the integrity of your configuration file
converge check

Try it out! You chould have a bunch more options!

.. code:: bash

converge --help

Example: Simple testing
=======================

create a converge.yaml as described above

.. code:: bash

converge init conf
mv converge.yaml.template converge.yaml
converge check

Create a sample repository structure

.. code:: bash

converge init repository target_directory

# you should now have the following structure
find target_directory/ -type d
# this is where the application centric data goes
./data
./data/default
./data/default/shared
./data/default/app
# the hierarchy file is situated here
./hierarchy
# target (or host for most) centric data resides here
./targets
./targets/hosts
./targets/mapping

Configuration
=============

converge.yaml
-------------

This file is a bit peculiar, it allows you to add programs, options,
configurations on the fly. Let's try it out before adding the
converge.yaml:

.. code:: bash

converge --help
# positional arguments:
# {init,check,version}
# init initialize configuration or repository
# check run sanity check on configuration
# version get converge version and build information

Put the following in a converge.yaml:

.. code:: yaml

conf:
default:
logging_level: "INFO"
programs:
# user command
amazingcommand:
# arguments expected by the command
args:
- "argument_one"
- "argument_two"
# description for the python help
description: "application description"
modes:
amazing_mode_one:
- "com.insane.class.path.Class1"
- "com.insane.class.path.Class2"
amazing_mode_two:
- "com.insane.class.path.Class1"
- "com.insane.class.path.Class3"

Now you should see a new option:

.. code:: bash

converge --help
# positional arguments:
# {init,check,version,amazingcommand}
# init initialize configuration or repository
# check run sanity check on configuration
# version get converge version and build information
# amazingcommand application description <-- MAGIC STUFF with description!!

And even more so there are sub-options available too:

.. code:: bash

converge amazingcommand --help
# usage: converge-runner.py amazingcommand [-h]
# argument_one argument_two
# {amazing_mode_two,amazing_mode_one}
#
# positional arguments:
# argument_one
# argument_two
# {amazing_mode_two,amazing_mode_one}

Classpath Execution Explained
-----------------------------

Those classpaths you listed under the modes, will be executed expecting
a method matching the following:

.. code:: python

def run(self, data, conf, **kwargs):
"""
Args:
data (dict): The data object that is passes and returned from all class runs
conf (dict): Dictionary of all configurations found in converge.yaml (directories, logging etc)
kwargs (object): magical python variable variable variables.

Returns:
dict: the data object that will be passed to all following class-runs.
"""
return data

Example: Configuration for Java property files
==============================================

A rough overview
================

A general example in diagram form:

.. figure:: docs/converge-diagram.png
:alt: Converge Overview

Alt text

A Brief History of Pain
=======================

You may have hit some (or all) of these stages in the pursuit of
configurability:

*In short: from the file, to the GUI, back to the file you idiot.*
#wevecomefullcircle \* Externalize configuration from your applications,
to avoid re-releases due to simple conf tuning \* Realizing that you're
now managing a million de-centralized files with no similar structure \*
Create or use a centralized, GUI/DB based configuration management
system (woohoo! configuration liberation!) \* Realizing that you are
missing flexibility, automation is complex, added abstraction layers are
painful.

The better model is to accept any data format, process it and output it
as you wish.

Files are better because: \* you can use time tested versioning systems
like git or mercurial to branch, release, rollback, check history \* you
can automate the modification of files with any tool you want \* doing
migrations/deployment/modifications on DB values/REST endpoints sucks
(unnecessarily complex)

.. |GitHub tag| image:: https://img.shields.io/github/tag/drewboswell/converge.svg
:target:
.. |GitHub release| image:: https://img.shields.io/github/release/drewboswell/converge.svg
:target:
.. |PyPI| image:: https://img.shields.io/pypi/v/pyconverge.svg
:target: https://pypi.python.org/pypi/pyconverge/
.. |Py Versions| image:: https://img.shields.io/pypi/pyversions/pyconverge.svg
:target: https://pypi.python.org/pypi/pyconverge/
.. |Build Status| image:: https://travis-ci.org/drewboswell/converge.svg?branch=master
:target: https://travis-ci.org/drewboswell/converge
.. |Coverage Status| image:: https://coveralls.io/repos/github/drewboswell/converge/badge.svg?branch=master
:target: https://coveralls.io/github/drewboswell/converge?branch=master
.. |Quality Gate| image:: https://sonarqube.com/api/badges/gate?key=drewboswell_converge
:target: https://sonarqube.com/dashboard/index/drewboswell_converge
.. |Code Smells| image:: https://sonarqube.com/api/badges/measure?key=drewboswell_converge&metric=code_smells
:target: https://sonarqube.com/dashboard/index/drewboswell_converge
.. |File Complexity| image:: https://sonarqube.com/api/badges/measure?key=drewboswell_converge&metric=file_complexity
:target: https://sonarqube.com/dashboard/index/drewboswell_converge
.. |Vulnerabilities| image:: https://sonarqube.com/api/badges/measure?key=drewboswell_converge&metric=vulnerabilities
:target: https://sonarqube.com/dashboard/index/drewboswell_converge
.. |Technical Dept| image:: https://sonarqube.com/api/badges/measure?key=drewboswell_converge&metric=sqale_debt_ratio
:target: https://sonarqube.com/dashboard/index/drewboswell_converge
.. |Lines of code| image:: https://sonarqube.com/api/badges/measure?key=drewboswell_converge&metric=ncloc
:target: https://sonarqube.com/dashboard/index/drewboswell_converge