HiYaPyCo 0.4.0

Hierarchical Yaml Python Config

HiYaPyCo - A Hierarchical Yaml Python Config

Description

A simple python lib allowing hierarchical overlay of config files in YAML syntax, offering different merge methods and variable interpolation based on jinja2.

The goal was to have something similar to puppets hiera deeper merge_behavior for python.

Key Features

• hierarchical overlay of multiple YAML files

• multiple merge methods for hierarchical YAML files

• variable interpolation using jinja2

Requirements

• PyYAML aka. python-yaml

• Jinja2 aka. python-jinja2

• ordereddict for python2.6 (if you like to use the Ordered Dict Yaml Loader / Dumper aka. ODYLDo)

Python Version

HiYaPyCo was designed to run on both current major python versions without changes. Tested versions:

• 2.6

• 2.7

• 3.2

Usage

A simple example:

import hiyapyco
conf = hiyapyco.load('yamlfile1' [,'yamlfile2' [,'yamlfile3' [...]]] [,kwargs])
print(hiyapyco.dump(conf))

real life example:

yaml1.yaml:

---
first: first element
second: xxx
deep:
    k1:
        - 1
        - 2

yaml2.yaml:

---
second: again {{ first }}
deep:
    k1:
        - 4
        - 6
    k2:
        - 3
        - 6

load …

>>> import pprint
>>> import hiyapyco
>>> conf = hiyapyco.load('yaml1.yaml', 'yaml2.yaml', method=hiyapyco.METHOD_MERGE, interpolate=True, failonmissingfiles=True)
>>> pprint.PrettyPrinter(indent=4).pprint(conf)
{   'deep': {   'k1': [1, 2, 4, 6], 'k2': [3, 6]},
    'first': u'first element',
    'ma': {   'ones': u'12', 'sum': u'22'},
    'second': u'again first element'}

real life example using yaml documents as strings

>>> import hiyapyco
>>> y1="""
... yaml: 1
... y:
...   y1: abc
...   y2: xyz
... """
>>> y2="""
... yaml: 2
... y:
...   y2: def
...   y3: XYZ
... """
>>> conf = hiyapyco.load([y1, y2], method=hiyapyco.METHOD_MERGE)
>>> print (conf)
OrderedDict([('yaml', 2), ('y', OrderedDict([('y1', 'abc'), ('y2', 'def'), ('y3', 'XYZ')]))])
>>> hiyapyco.dump(conf, default_flow_style=True)
'{yaml: 2, y: {y1: abc, y2: def, y3: XYZ}}\n'

args

All args are handled as file names or yaml documents. They may be strings or list of strings.

kwargs

• method: bit (one of the listed below):

  • hiyapyco.METHOD_SIMPLE: replace values (except for lists a simple merge is performed) (default method)

  • hiyapyco.METHOD_MERGE: perform a deep merge

• interpolate: boolean : perform interpolation after the merge (default: False)

• usedefaultyamlloader: boolean : force the usage of the default PyYAML loader/dumper instead of HiYaPyCos implementation of a OrderedDict loader/dumper (see: Ordered Dict Yaml Loader / Dumper aka. ODYLDo) (default: False)

• failonmissingfiles: boolean : fail if a supplied YAML file can not be found (default: True)

• loglevel: int : loglevel for the hiyapyco logger; should be one of the valid levels from logging: ‘WARN’, ‘ERROR’, ‘DEBUG’, ‘I NFO’, ‘WARNING’, ‘CRITICAL’, ‘NOTSET’ (default: default of logging)

• loglevelmissingfiles: int : one of the valid levels from logging: ‘WARN’, ‘ERROR’, ‘DEBUG’, ‘INFO’, ‘WARNING’, ‘CRITICAL’, ‘NOTSET’ (default: logging.ERROR if failonmissingfiles = True, else logging.WARN)

interpolation

For using interpolation, I strongly recomend not to use the default PyYAML loader, as it sorts the dict entrys alphabetically, a fact that may break interpolation in some cases (see test/odict.yaml and test/test_odict.py for an example). See Ordered Dict Yaml Loader / Dumper aka. ODYLDo

default

The default jinja2.Environment for the interpolation is

hiyapyco.jinja2env = Environment(undefined=Undefined)

This means that undefined vars will be ignored and replaced with a empty string.

change the jinja2 Environment

If you like to change the jinja2 Environment used for the interpolation, set hiyapyco.jinja2env before calling hiyapyco.load!

use jinja2 DebugUndefined

If you like to keep the undefined var as string but raise no error, use

from jinja2 import Environment, Undefined, DebugUndefined, StrictUndefined
hiyapyco.jinja2env = Environment(undefined=DebugUndefined)

use jinja2 StrictUndefined

If you like to raise a error on undefined vars, use

from jinja2 import Environment, Undefined, DebugUndefined, StrictUndefined
hiyapyco.jinja2env = Environment(undefined=StrictUndefined)

This will raise a hiyapyco.HiYaPyCoImplementationException wrapped arround the jinja2.UndefinedError pointing at the strig causing the error.

more informations

See: jinja2.Environment

Ordered Dict Yaml Loader / Dumper aka. ODYLDo

This is a simple implementation of a PyYAML loader / dumper using OrderedDict from collections. Because chaos is fun but order matters on loading dicts from a yaml file. In order to use this on python 2.6, please install ordereddict:

sudo pip-2.6 install ordereddict

Install

From Source

GitHub

git clone https://github.com/zerwes/hiyapyco
cd hiyapyco
sudo python setup.py install

PyPi

Download the latest or desired version of the source package from https://pypi.python.org/pypi/HiYaPyCo. Unpack the archive and install by executing:

sudo python setup.py install

pip

Install the latest wheel package using:

pip install HiYaPyCo

debian packages

echo "deb http://repo.zero-sys.net/hiyapyco/deb ./" > /etc/apt/sources.list.d/hiyapyco.list
gpg --keyserver keys.gnupg.net --recv-key ED7D414C
# or use:
wget http://jwhoisserver.net/key.asc -O - | gpg --import -
gpg --armor --export ED7D414C | apt-key add -
apt-get update
apt-get install python3-hiyapyco python-hiyapyco

rpm packages

use http://repo.zero-sys.net/hiyapyco/rpm as URL for the yum repo and http://jwhoisserver.net/key.asc as the URL for the key.

License

3. 2014 Klaus Zerwes zero-sys.net

This package is free software. This software is licensed under the terms of the GNU LESSER GENERAL PUBLIC LICENSE version 3 or later, as published by the Free Software Foundation. See https://www.gnu.org/licenses/lgpl.html

Changelog

0.1.0 / 0.1.1

Initial release

0.2.0

Fixed unicode handling

0.3.0 / 0.3.1

Implemented a Ordered Dict Yaml Loader

0.3.2

Improved tests and bool args checks