buildstream/_mirror.py

#!/usr/bin/env python3
#
#  Copyright (C) 2018 Codethink Limited
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU Lesser General Public
#  License as published by the Free Software Foundation; either
#  version 2 of the License, or (at your option) any later version.
#
#  This library is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#  Lesser General Public License for more details.
#
#  You should have received a copy of the GNU Lesser General Public
#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
#
#  Authors:
#        Jonathan Maw <jonathan.maw@codethink.co.uk>


from . import utils
from . import _yaml
from ._exceptions import ImplError, LoadError, LoadErrorReason


# MirrorKind()
#
# Defines the kind of mirrors that buildstream is capable of handling.
class MirrorKind():

    # The default type of mirror, replace the alias
    DEFAULT = 'default'

    # A mirror generated by buildstream
    BST_GENERATED = 'bst-generated'


class Mirror():
    def __init__(self, node):
        self.location = _yaml.node_get(node, str, "location-name")

    def get_mirror_uris(self, uri, source):
        raise ImplError("Base mirror class does not implement get_mirror_uri")


class DefaultMirror(Mirror):
    def __init__(self, node):
        super().__init__(node)
        allowed_fields = ['location-name', 'aliases', 'mirror-kind']
        _yaml.node_validate(node, allowed_fields)

        self.aliases = {}
        for alias_mapping, uris in _yaml.node_items(node['aliases']):
            assert isinstance(uris, list)
            self.aliases[alias_mapping] = list(uris)

    def get_mirror_uris(self, uri, source):
        url_prefix, url_body = uri.split(utils._ALIAS_SEPARATOR, 1)
        for alias_uri in self.aliases.get(url_prefix, []):
            yield alias_uri + url_body, False


class BstGeneratedMirror(Mirror):
    def __init__(self, node):
        super().__init__(node)
        allowed_fields = [
            'location-name', 'mirror-kind', 'site', 'aliases-covered'
        ]
        _yaml.node_validate(node, allowed_fields)
        self.site = _yaml.node_get(node, str, 'site')
        if '://' in self.site:
            provenance = _yaml.node_get_provenance(node, key='site')
            raise LoadError(LoadErrorReason.INVALID_DATA,
                            '{}: Site should not contain a URI prefix'.format(provenance))
        self.aliases_covered = _yaml.node_get(node, list, 'aliases-covered')

    def get_mirror_uris(self, uri, source):
        yield source.get_normalised_mirror_path(uri, prefix=self.site), True