Klortho · April 21, 2016 16:30
diff --git a/0-settings.py b/0-settings.py
 #!/usr/bin/env python

 from os import path, getenv
 import settings_deferrer as s

 # Put normal settings here, if you want, or put them all into the `fill_defaults()`
 # function below. If the latter, though, you'll have to use the `s.MY_SETTING` syntax.
 MY_SETTING = 'zormulon'
 # ...

 # This function is executed later, after the overrides are brought in. It defines
 # all of the *default* settings, any of which can be overridden, even if they are
 # dependent on each other.
 def fill_defaults():

  # Here's the default for the `JIG_BASE` setting.
  s.JIG_BASE = 'https://www.ncbi.nlm.nih.gov'
  
  # Default for `JIG_VERSION` -- we'll override this
  s.JIG_VERSION = '1.14.7'
  
  # Default for computing `JIG_URL` from previously-defined settings. In a naive settings.py,
  # you wouldn't be able to override JIG_VERSION in this statement -- it would use the value
  # just assigned above.
  # This works by proxying through getters and setters in the `s` object. This was as clean
  # a syntax as I was able to come up with.
  s.JIG_URL = s.JIG_BASE + '/core/jig/' + s.JIG_VERSION + '/js/jig.min.js'

 # Here we override JIG_VERSION. This is where we'd use settings_overrider to get values
 # from yaml or env. vars.
 JIG_VERSION = '2.5'

 # This method finishes filling in everything
 s.config(globals(), fill_defaults)


 print('Final settings: ')
 print('  JIG_BASE: ' + JIG_BASE)
 print('  JIG_VERSION: ' + JIG_VERSION)
 print('  JIG_URL: ' + JIG_URL)
diff --git a/1-settings_deferrer.py b/1-settings_deferrer.py
 import sys

 class SettingsDeferrer(object):

  # Direct get, private:
  def _get(self, name):
    d = self.__dict__
    return d[name] if name in d else None

  def _set(self, name, value):
    self.__dict__[name] = value

  # If an overrides value is set, return that; otherwise, return
  # the default
  def __getattr__(self, name):
    merged = self._get('merged')
    v = merged[name] if (merged and name in merged) else None
    return v

  # This gets called from within fill_defaults. It only sets the value in 
  # `merged` if there isn't something there already
  def __setattr__(self, name, value):
    merged = self._get('merged')
    if not(merged): return
    if not(name in merged): merged[name] = value

  def config(self, _overrides, fill_defaults):
    self._set('merged', _overrides)
    fill_defaults()

 this = SettingsDeferrer()
 sys.modules[__name__] = this
diff --git a/2-requirements.txt b/2-requirements.txt
 Django~=1.9.0
 settings-overrider~=0.5
	#!/usr/bin/env python

	from os import path, getenv
	import settings_deferrer as s

	# Put normal settings here, if you want, or put them all into the `fill_defaults()`
	# function below. If the latter, though, you'll have to use the `s.MY_SETTING` syntax.
	MY_SETTING = 'zormulon'
	# ...

	# This function is executed later, after the overrides are brought in. It defines
	# all of the default settings, any of which can be overridden, even if they are
	# dependent on each other.
	def fill_defaults():

	# Here's the default for the `JIG_BASE` setting.
	s.JIG_BASE = 'https://www.ncbi.nlm.nih.gov'

	# Default for `JIG_VERSION` -- we'll override this
	s.JIG_VERSION = '1.14.7'

	# Default for computing `JIG_URL` from previously-defined settings. In a naive settings.py,
	# you wouldn't be able to override JIG_VERSION in this statement -- it would use the value
	# just assigned above.
	# This works by proxying through getters and setters in the `s` object. This was as clean
	# a syntax as I was able to come up with.
	s.JIG_URL = s.JIG_BASE + '/core/jig/' + s.JIG_VERSION + '/js/jig.min.js'

	# Here we override JIG_VERSION. This is where we'd use settings_overrider to get values
	# from yaml or env. vars.
	JIG_VERSION = '2.5'

	# This method finishes filling in everything
	s.config(globals(), fill_defaults)


	print('Final settings: ')
	print(' JIG_BASE: ' + JIG_BASE)
	print(' JIG_VERSION: ' + JIG_VERSION)
	print(' JIG_URL: ' + JIG_URL)
	import sys

	class SettingsDeferrer(object):

	# Direct get, private:
	def _get(self, name):
	d = self.__dict__
	return d[name] if name in d else None

	def _set(self, name, value):
	self.__dict__[name] = value

	# If an overrides value is set, return that; otherwise, return
	# the default
	def __getattr__(self, name):
	merged = self._get('merged')
	v = merged[name] if (merged and name in merged) else None
	return v

	# This gets called from within fill_defaults. It only sets the value in
	# `merged` if there isn't something there already
	def __setattr__(self, name, value):
	merged = self._get('merged')
	if not(merged): return
	if not(name in merged): merged[name] = value

	def config(self, _overrides, fill_defaults):
	self._set('merged', _overrides)
	fill_defaults()

	this = SettingsDeferrer()
	sys.modules[__name__] = this