bootstrap-vz/bootstrapvz/base/pkg/sourceslist.py

class SourceLists(object):
	"""Represents a list of sources lists for apt
	"""

	def __init__(self, manifest_vars):
		"""
		:param dict manifest_vars: The manifest variables
		"""
		# A dictionary with the name of the file in sources.list.d as the key
		# That values are lists of Source objects
		self.sources = {}
		# Save the manifest variables, we need the later on
		self.manifest_vars = manifest_vars

	def add(self, name, line):
		"""Adds a source to the apt sources list

		:param str name: Name of the file in sources.list.d, may contain manifest vars references
		:param str line: The line for the source file, may contain manifest vars references
		"""
		name = name.format(**self.manifest_vars)
		line = line.format(**self.manifest_vars)
		if name not in self.sources:
			self.sources[name] = []
		self.sources[name].append(Source(line))

	def target_exists(self, target):
		"""Checks whether the target exists in the sources list

		:param str target: Name of the target to check for, may contain manifest vars references

		:return: Whether the target exists
		:rtype: bool
		"""
		target = target.format(**self.manifest_vars)
		# Run through all the sources and return True if the target exists
		for lines in self.sources.itervalues():
			if target in (source.distribution for source in lines):
				return True
		return False


class Source(object):
	"""Represents a single source line
	"""

	def __init__(self, line):
		"""
		:param str line: A apt source line

		:raises SourceError: When the source line cannot be parsed
		"""
		# Parse the source line and populate the class attributes with it
		# The format is taken from `man sources.list`
		# or: http://manpages.debian.org/cgi-bin/man.cgi?sektion=5&query=sources.list&apropos=0&manpath=sid&locale=en
		import re
		regexp = re.compile('^(?P<type>deb|deb-src)\s+'
		                    '(\[\s*(?P<options>.+\S)?\s*\]\s+)?'
		                    '(?P<uri>\S+)\s+'
		                    '(?P<distribution>\S+)'
		                    '(\s+(?P<components>.+\S))?\s*$')
		match = regexp.match(line).groupdict()
		if match is None:
			from exceptions import SourceError
			raise SourceError('Unable to parse source line: ' + line)
		self.type = match['type']
		self.options = []
		if match['options'] is not None:
			self.options = re.sub(' +', ' ', match['options']).split(' ')
		self.uri = match['uri']
		self.distribution = match['distribution']
		self.components = []
		if match['components'] is not None:
			self.components = re.sub(' +', ' ', match['components']).split(' ')

	def __str__(self):
		"""Convert the object into a source line
		This is pretty much the reverse of what we're doing in the initialization function.

		:rtype: str
		"""
		options = ''
		if len(self.options) > 0:
			options = ' [{options}]'.format(options=' '.join(self.options))

		components = ''
		if len(self.components) > 0:
			components = ' {components}'.format(components=' '.join(self.components))

		return ('{type}{options} {uri} {distribution}{components}'
		        .format(type=self.type, options=options,
		                uri=self.uri, distribution=self.distribution,
		                components=components))