README.rst
conff
=====
Simple config parser with evaluator library.
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Why Another Config Parser Module?
---------------------------------
This project inspired of the necessity complex config in a project. By means complex:
- Reusability
- Import values from file
- Reference values from other object
- Secure
- Encrypt/decrypt sensitive values
- Flexible
- Make logical expression to derive values
- Combine with `jinja2 <http://jinja.pocoo.org/docs/2.10/>`_ template based
- Powerful
- Add custom functions in Python
- Link name data from Python
Real World Examples
-------------------
All the example below located in `data directory <https://github.com/kororo/conff/tree/master/conff/data>`_.
Imagine you start an important project, your code need to analyse image/videos which involves workflow
with set of tasks with AWS Rekognition. The steps will be more/less like this:
1. Read images/videos from a specific folder, if images goes to (2), if videos goes to (3).
2. Analyse the images with AWS API, then goes (4)
3. Analyse the videos with AWS API, then goes (4)
4. Write the result back to JSON file, finished
The configuration required:
1. Read images/videos (where is the folder)
2. Analyse images (AWS API credential and max resolution for image)
3. Analyse videos (AWS API credential and max resolution for video)
4. Write results (where is the result should be written)
1. Without conff library
^^^^^^^^^^^^^^^^^^^^^^^^
File: `data/sample_config_01.yml <https://github.com/kororo/conff/tree/master/conff/data/sample_config_01.yml>`_
Where it is all started, if we require to store the configuration as per normally, it should be like this.
.. code:: yaml
job:
read_image:
# R01
root_path: /data/project/images_and_videos/
analyse_image:
# R02
api_cred:
region_name: ap-southeast-2
aws_access_key_id: ACCESSKEY1234
# R03
aws_secret_access_key: ACCESSSECRETPLAIN1234
max_res: [1024, 768]
analyse_video:
# R04
api_cred:
region_name: ap-southeast-2
aws_access_key_id: ACCESSKEY1234
aws_secret_access_key: ACCESSSECRETPLAIN1234
max_res: [800, 600]
write_result:
# R05
output_path: /data/project/result.json
.. code:: python
import yaml
with open('data/sample_config_01.yml') as stream:
r1 = yaml.safe_load(stream)
Notes:
- R01: The subpath of "/data/project" is repeated between R01 and R05
- R02: api_cred is repeatedly defined with R04
- R03: the secret is plain visible, if this stored in GIT, it is pure disaster
2. Fix the repeat
^^^^^^^^^^^^^^^^^
File: `data/sample_config_02.yml <https://github.com/kororo/conff/tree/master/conff/data/sample_config_02.yml>`_
Repeating values/configuration is bad, this could potentially cause human mistake if changes made is not
consistently applied in all occurences.
.. code:: yaml
# this can be any name, as long as not reserved in Python
shared:
project_path: /data/project
aws_cred:
region_name: ap-southeast-2
aws_access_key_id: ACCESSKEY1234
# F03
aws_secret_access_key: F.decrypt('gAAAAABbBBhOJDMoQSbF9jfNgt97FwyflQEZRxv2L2buv6YD_Jiq8XNrxv8VqFis__J7YlpZQA07nDvzYwMU562Mlm978uP9BQf6M9Priy3btidL6Pm406w=')
job:
read_image:
# F01
root_path: R.shared.project_path + '/images_and_videos/'
analyse_image:
# F02
api_cred: R.shared.aws_cred
max_res: [1024, 768]
analyse_video:
# F04
api_cred: R.shared.aws_cred
max_res: [800, 600]
write_result:
# F05
output_path: R.shared.project_path + '/result.json'
.. code:: python
import conff
# ekey is the secured encryption key
# WARNING: this is just demonstration purposes
ekey = 'FOb7DBRftamqsyRFIaP01q57ZLZZV6MVB2xg1Cg_E7g='
r2 = conff.load(fs_path='data/sample_config_02.yml', params={'ekey': ekey})
Notes:
- F01: it is safe if the prefix '/data/project' need to be changed, it will automatically changed for F05
- F02: no more duplicated config with F04
- F03: it is secured to save this to GIT, as long as the encryption key is stored securely somewhere in server such
as ~/.secret
3. Optimise to the extreme
^^^^^^^^^^^^^^^^^^^^^^^^^^
File: `data/sample_config_03.yml <https://github.com/kororo/conff/tree/master/conff/data/sample_config_03.yml>`_
This is just demonstration purposes to see the full capabilities of this library.
.. code:: yaml
# this can be any name, as long as not reserved in Python
shared:
project_path: /data/project
analyse_image_video:
api_cred:
region_name: ap-southeast-2
aws_access_key_id: ACCESSKEY1234
aws_secret_access_key: F.decrypt('gAAAAABbBBhOJDMoQSbF9jfNgt97FwyflQEZRxv2L2buv6YD_Jiq8XNrxv8VqFis__J7YlpZQA07nDvzYwMU562Mlm978uP9BQf6M9Priy3btidL6Pm406w=')
max_res: [1024, 768]
job:
read_image:
root_path: R.shared.project_path + '/images_and_videos/'
analyse_image: R.shared.analyse_image_video
analyse_video:
F.extend: R.shared.analyse_image_video
F.update:
max_res: [800, 600]
write_result:
output_path: R.shared.project_path + '/result.json'
For completeness, ensuring data is consistent and correct between sample_config_01.yml, sample_config_02.yml
and sample_config_03.yml.
.. code:: python
# nose2 conff.test.ConffTestCase.test_sample
fs_path = 'data/sample_config_01.yml'
with open(fs_path) as stream:
r1 = yaml.safe_load(stream)
fs_path = 'data/sample_config_02.yml'
ekey = 'FOb7DBRftamqsyRFIaP01q57ZLZZV6MVB2xg1Cg_E7g='
r2 = conff.load(fs_path=fs_path, params={'ekey': ekey})
fs_path = 'data/sample_config_03.yml'
r3 = conff.load(fs_path=fs_path, params={'ekey': ekey})
self.assertDictEqual(r1['job'], r2['job'], 'Mismatch value')
self.assertDictEqual(r2['job'], r3['job'], 'Mismatch value')
Feedback and Discussion
-----------------------
Come to Gitter channel to discuss, pass any feedbacks and suggestions. If you like to be contributor, please do let me know.
Important Notes
---------------
Parsing Order
^^^^^^^^^^^^^
conff will only parse and resolve variable/names top to bottom order. Please ensure you arrange your configuration
in the same manner, there is no auto-dependencies resolver to handle complex and advanced names currently.
dict vs collections.OrderedDict
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In Python 3.5, the dict data type has inconsistent ordering, it is **STRONGLY** recommended to use **OrderedDict** if
you manually parse object. If you load from YAML file, the library already handled it. The reason of order is important,
this due to simplification and assumption of order execution. The library will parse the values from top to bottom as
per order in the key-value dictionary.
Install
-------
.. code:: bash
[sudo] pip install conff
Basic Usage
-----------
To get very basic parsing:
Simple parse
^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser()
r = p.parse({'math': '1 + 3'})
assert r == {'math': 4}
Load YAML file
^^^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser()
r = p.load('path_of_file.yml')
Template based config
^^^^^^^^^^^^^^^^^^^^^
Using `jinja2 <http://jinja.pocoo.org/docs/2.10/>`_ to craft more powerful config.
.. code:: python
import conff
p = conff.Parser()
r = p.parse('F.template("{{ 1 + 2 }}")')
assert r == 3
Examples
--------
More advances examples:
Parse with simple expression
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser()
r = p.parse('1 + 2')
assert r == 3
Parse object
^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser()
r = p.parse({"math": "1 + 2"})
assert r == {'math': 3}
Ignore expression (declare it as string)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser()
r = conff.parse('"1 + 2"')
assert r == '1 + 2'
Parse error behaviours
^^^^^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser()
r = p.parse({'math': '1 / 0'})
# Exception raised
# ZeroDivisionError: division by zero
import files
^^^^^^^^^^^^
.. code:: python
import conff
## y1.yml
# shared_conf: 1
## y2.yml
# conf: F.inc('y1.yml')
p = conff.Parser()
r = p.load('y2.yml')
assert r == {'conf': {'shared_conf': 1}}
Parse with functions
^^^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
def fn_add(a, b):
return a + b
p = conff.Parser(fns={'add': fn_add})
r = p.parse('F.add(1, 2)')
assert r == 3
Parse with names
^^^^^^^^^^^^^^^^
.. code:: python
import conff
p = conff.Parser(names={'a': 1, 'b': 2})
r = conff.parse('a + b')
assert r == 3
Parse with extends
^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
data = {
't1': {'a': 'a'},
't2': {
'F.extend': 'R.t1',
'b': 'b'
}
}
p = conff.Parser()
r = p.parse(data)
assert r == {'t1': {'a': 'a'}, 't2': {'a': 'a', 'b': 'b'}}
Parse with updates
^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
data = {
't1': {'a': 'a'},
't2': {
'b': 'b',
'F.update': {
'c': 'c'
},
}
}
p = conff.Parser()
r = p.parse(data)
assert r == {'t1': {'a': 'a'}, 't2': {'b': 'b', 'c': 'c'}}
Parse with extends and updates
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. code:: python
import conff
data = {
't1': {'a': 'a'},
't2': {
'F.extend': 'R.t1',
'b': 'b',
'F.update': {
'a': 'A',
'c': 'c'
},
}
}
p = conff.Parser()
r = p.parse(data)
assert r == {'t1': {'a': 'a'}, 't2': {'a': 'A', 'b': 'b', 'c': 'c'}}
Create a list of values
^^^^^^^^^^^^^^^^^^^^^^^
This creates a list of floats, similar to numpy.linspace
.. code:: python
import conff
data = {'t2': 'F.linspace(0, 10, 5)'}
p = conff.Parser()
r = p.parse(data)
assert r == {'t2': [0.0, 2.5, 5.0, 7.5, 10.0]}
This also creates a list of floats, but behaves like numpy.arange (although
slightly different in that it is inclusive of the endpoint).
.. code:: python
import conff
data = {'t2': 'F.arange(0, 10, 2)'}
p = conff.Parser()
r = p.parse(data)
assert r == {'t2': [0, 2, 4, 6, 8, 10]}
Parse with for each
^^^^^^^^^^^^^^^^^^^
One can mimic the logic of a for loop with the following example
.. code:: python
import conff
data = {'t1': 2,
'F.foreach': {
'values': 'F.linspace(0, 10, 2)',
# You have access to loop.index, loop.value, and loop.length
# within the template, as well as all the usual names
'template': {
'"test%i"%loop.index': 'R.t1*loop.value',
'length': 'loop.length'
}
}
}
p = conff.Parser()
r = p.parse(data)
assert r == {'length': 3, 't1': 2, 'test0': 0.0, 'test1': 10.0, 'test2': 20.0}
Encryption
----------
This section to help you to quickly generate encryption key, initial encrypt values and test to decrypt the value.
.. code:: python
import conff
# generate key, save it somewhere safe
names = {'R': {'_': {'etype': 'fernet'}}}
etype = conff.generate_key(names)()
# or just
ekey = conff.generate_key()('fernet')
# encrypt data
# BIG WARNING: this should be retrieved somewhere secured for example in ~/.secret
# below just for example purposes
ekey = 'FOb7DBRftamqsyRFIaP01q57ZLZZV6MVB2xg1Cg_E7g='
names = {'R': {'_': {'etype': 'fernet', 'ekey': ekey}}}
# gAAAAABbBBhOJDMoQSbF9jfNgt97FwyflQEZRxv2L2buv6YD_Jiq8XNrxv8VqFis__J7YlpZQA07nDvzYwMU562Mlm978uP9BQf6M9Priy3btidL6Pm406w=
encrypted_value = conff.encrypt(names)('ACCESSSECRETPLAIN1234')
# decrypt data
ekey = 'FOb7DBRftamqsyRFIaP01q57ZLZZV6MVB2xg1Cg_E7g='
names = {'R': {'_': {'etype': 'fernet', 'ekey': ekey}}}
encrypted_value = 'gAAAAABbBBhOJDMoQSbF9jfNgt97FwyflQEZRxv2L2buv6YD_Jiq8XNrxv8VqFis__J7YlpZQA07nDvzYwMU562Mlm978uP9BQf6M9Priy3btidL6Pm406w='
conff.decrypt(names)(encrypted_value)
Test
----
To test this project:
.. code:: bash
# default test
nose2
# test with coverage
nose2 --with-coverage
# test specific
nose2 conff.test.ConffTestCase.test_sample
TODO
----
- [X] Setup basic necessity
- [X] Stop procrastinating
- [X] Project registration in pypi
- [X] Create unit tests
- [X] Setup travis
- [X] Setup coveralls
- [ ] Add more support on `Python versions <https://en.wikipedia.org/wiki/CPython#Version_history>`_
- [ ] 2.7
- [ ] 3.4
- [X] 3.5
- [X] 3.6
- [ ] Features
- Wish List Features now moved to `wiki page <https://github.com/kororo/conff/wiki/Wish-List-Features>`_.
- [ ] Improve docs
- [ ] Add more code comments and visibilities
- [ ] Make github layout code into two left -> right
- [X] Put more examples
- [ ] Setup readthedocs
- [ ] Add code conduct, issue template into git project.
- [ ] Add information that conff currently accept YML and it not limited, it can take any objects
Other Open Source
-----------------
This project uses other awesome projects:
- `cryptography <https://github.com/pyca/cryptography>`_
- `jinja2 <http://jinja.pocoo.org/docs/2.10/>`_
- `munch <https://github.com/Infinidat/munch>`_
- `simpleeval <https://github.com/danthedeckie/simpleeval>`_
- `yaml <https://github.com/yaml/pyyaml>`_
Who uses conff?
---------------
Please send a PR to keep the list growing, if you may please add your handle and company.