71 lines
2.1 KiB
Python
71 lines
2.1 KiB
Python
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import os
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import tarfile
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import marisa_trie
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from util.registry.aufs import is_aufs_metadata, get_deleted_prefix
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from util.registry.tarlayerformat import TarLayerFormat
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class StreamLayerMerger(TarLayerFormat):
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""" Class which creates a generator of the combined TAR data for a set of Docker layers. """
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def __init__(self, get_tar_stream_iterator, path_prefix=None, reporter=None):
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super(StreamLayerMerger, self).__init__(get_tar_stream_iterator, path_prefix, reporter=reporter)
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self.path_trie = marisa_trie.Trie()
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self.path_encountered = set()
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self.deleted_prefix_trie = marisa_trie.Trie()
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self.deleted_prefixes_encountered = set()
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def after_tar_layer(self):
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# Update the tries.
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self.path_trie = marisa_trie.Trie(self.path_encountered)
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self.deleted_prefix_trie = marisa_trie.Trie(self.deleted_prefixes_encountered)
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@staticmethod
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def _normalize_path(path):
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return os.path.relpath(path.decode('utf-8'), './')
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def _check_deleted(self, absolute):
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ubsolute = unicode(absolute)
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for prefix in self.deleted_prefix_trie.iter_prefixes(ubsolute):
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if not os.path.relpath(ubsolute, prefix).startswith('..'):
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return True
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return False
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def is_skipped_file(self, filename):
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absolute = StreamLayerMerger._normalize_path(filename)
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# Skip metadata.
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if is_aufs_metadata(absolute):
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return True
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# Check if the file is under a deleted path.
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if self._check_deleted(absolute):
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return True
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# Check if this file has already been encountered somewhere. If so,
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# skip it.
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ubsolute = unicode(absolute)
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if ubsolute in self.path_trie:
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return True
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return False
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def should_append_file(self, filename):
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if self.is_skipped_file(filename):
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return False
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absolute = StreamLayerMerger._normalize_path(filename)
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# Add any prefix of deleted paths to the prefix list.
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deleted_prefix = get_deleted_prefix(absolute)
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if deleted_prefix is not None:
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self.deleted_prefixes_encountered.add(deleted_prefix)
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return False
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# Otherwise, add the path to the encountered list and return it.
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self.path_encountered.add(absolute)
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return True
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