bootstrap-vz/bootstrapvz/plugins/minimize_size/tasks/dpkg.py

from bootstrapvz.base import Task
from bootstrapvz.common import phases
from bootstrapvz.common.tasks import bootstrap
from bootstrapvz.common.tasks import workspace
from bootstrapvz.common.tools import sed_i
import os
import shutil
from . import assets


class CreateDpkgCfg(Task):
	description = 'Creating /etc/dpkg/dpkg.cfg.d before bootstrapping'
	phase = phases.os_installation
	successors = [bootstrap.Bootstrap]

	@classmethod
	def run(cls, info):
		os.makedirs(os.path.join(info.root, 'etc/dpkg/dpkg.cfg.d'))


class InitializeBootstrapFilterList(Task):
	description = 'Initializing the bootstrapping filter list'
	phase = phases.preparation

	@classmethod
	def run(cls, info):
		info._minimize_size['bootstrap_filter'] = {'exclude': [], 'include': []}


class CreateBootstrapFilterScripts(Task):
	description = 'Creating the bootstrapping locales filter script'
	phase = phases.os_installation
	successors = [bootstrap.Bootstrap]
	# Inspired by:
	# https://github.com/docker/docker/blob/1d775a54cc67e27f755c7338c3ee938498e845d7/contrib/mkimage/debootstrap

	@classmethod
	def run(cls, info):
		if info.bootstrap_script is not None:
			from bootstrapvz.common.exceptions import TaskError
			raise TaskError('info.bootstrap_script seems to already be set '
			                'and is conflicting with this task')

		bootstrap_script = os.path.join(info.workspace, 'bootstrap_script.sh')
		filter_script = os.path.join(info.workspace, 'bootstrap_files_filter.sh')
		excludes_file = os.path.join(info.workspace, 'debootstrap-excludes')

		shutil.copy(os.path.join(assets, 'bootstrap-script.sh'), bootstrap_script)
		shutil.copy(os.path.join(assets, 'bootstrap-files-filter.sh'), filter_script)

		sed_i(bootstrap_script, r'DEBOOTSTRAP_EXCLUDES_PATH', excludes_file)
		sed_i(bootstrap_script, r'BOOTSTRAP_FILES_FILTER_PATH', filter_script)

		# We exclude with patterns but include with fixed strings
		# The pattern matching when excluding is needed in order to filter
		# everything below e.g. /usr/share/locale but not the folder itself
		filter_lists = info._minimize_size['bootstrap_filter']
		exclude_list = '\|'.join(map(lambda p: '.' + p + '.\+', filter_lists['exclude']))
		include_list = '\n'.join(map(lambda p: '.' + p, filter_lists['include']))
		sed_i(filter_script, r'EXCLUDE_PATTERN', exclude_list)
		sed_i(filter_script, r'INCLUDE_PATHS', include_list)
		os.chmod(filter_script, 0755)

		info.bootstrap_script = bootstrap_script
		info._minimize_size['filter_script'] = filter_script


class FilterLocales(Task):
	description = 'Configuring dpkg and debootstrap to only include specific locales/manpages when installing packages'
	phase = phases.os_installation
	predecessors = [CreateDpkgCfg]
	successors = [CreateBootstrapFilterScripts]
	# Snatched from:
	# https://github.com/docker/docker/blob/1d775a54cc67e27f755c7338c3ee938498e845d7/contrib/mkimage/debootstrap
	# and
	# https://raphaelhertzog.com/2010/11/15/save-disk-space-by-excluding-useless-files-with-dpkg/

	@classmethod
	def run(cls, info):
		# Filter when debootstrapping
		info._minimize_size['bootstrap_filter']['exclude'].extend([
			'/usr/share/locale/',
			'/usr/share/man/',
		])

		locales = info.manifest.plugins['minimize_size']['dpkg']['locales']
		info._minimize_size['bootstrap_filter']['include'].extend([
			'/usr/share/locale/locale.alias',
			'/usr/share/man/man1',
			'/usr/share/man/man2',
			'/usr/share/man/man3',
			'/usr/share/man/man4',
			'/usr/share/man/man5',
			'/usr/share/man/man6',
			'/usr/share/man/man7',
			'/usr/share/man/man8',
			'/usr/share/man/man9',
		] +
			map(lambda l: '/usr/share/locale/' + l + '/', locales) +
			map(lambda l: '/usr/share/man/' + l + '/', locales)
		)

		# Filter when installing things with dpkg
		locale_lines = ['path-exclude=/usr/share/locale/*',
		                'path-include=/usr/share/locale/locale.alias']
		manpages_lines = ['path-exclude=/usr/share/man/*',
		                  'path-include=/usr/share/man/man[1-9]']

		locales = info.manifest.plugins['minimize_size']['dpkg']['locales']
		locale_lines.extend(map(lambda l: 'path-include=/usr/share/locale/' + l + '/*', locales))
		manpages_lines.extend(map(lambda l: 'path-include=/usr/share/man/' + l + '/*', locales))

		locales_path = os.path.join(info.root, 'etc/dpkg/dpkg.cfg.d/10filter-locales')
		manpages_path = os.path.join(info.root, 'etc/dpkg/dpkg.cfg.d/10filter-manpages')

		with open(locales_path, 'w') as locale_filter:
			locale_filter.write('\n'.join(locale_lines) + '\n')
		with open(manpages_path, 'w') as manpages_filter:
			manpages_filter.write('\n'.join(manpages_lines) + '\n')


class ExcludeDocs(Task):
	description = 'Configuring dpkg and debootstrap to not install additional documentation for packages'
	phase = phases.os_installation
	predecessors = [CreateDpkgCfg]
	successors = [CreateBootstrapFilterScripts]

	@classmethod
	def run(cls, info):
		# "Packages must not require the existence of any files in /usr/share/doc/ in order to function [...]."
		# Source: https://www.debian.org/doc/debian-policy/ch-docs.html
		# So doing this should cause no problems.
		info._minimize_size['bootstrap_filter']['exclude'].append('/usr/share/doc/')
		exclude_docs_path = os.path.join(info.root, 'etc/dpkg/dpkg.cfg.d/10exclude-docs')
		with open(exclude_docs_path, 'w') as exclude_docs:
			exclude_docs.write('path-exclude=/usr/share/doc/*\n')


class DeleteBootstrapFilterScripts(Task):
	description = 'Deleting the bootstrapping locales filter script'
	phase = phases.cleaning
	successors = [workspace.DeleteWorkspace]

	@classmethod
	def run(cls, info):
		os.remove(info._minimize_size['filter_script'])
		del info._minimize_size['filter_script']
		os.remove(info.bootstrap_script)