73 lines
1.8 KiB
Python
73 lines
1.8 KiB
Python
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import re
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LINE_CONTINUATION_REGEX = re.compile('\s*\\\s*\n')
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COMMAND_REGEX = re.compile('([A-Z]+)\s(.*)')
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COMMENT_CHARACTER = '#'
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class ParsedDockerfile(object):
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def __init__(self, commands):
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self.commands = commands
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def get_commands_of_kind(self, kind):
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return [command for command in self.commands if command['command'] == kind]
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def get_base_image(self):
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image_and_tag = self.get_base_image_and_tag()
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if not image_and_tag:
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return None
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# Note:
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# Dockerfile images references can be of multiple forms:
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# server:port/some/path
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# somepath
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# server/some/path
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# server/some/path:tag
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# server:port/some/path:tag
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parts = image_and_tag.strip().split(':')
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if len(parts) == 1:
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# somepath
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return parts[0]
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# Otherwise, determine if the last part is a port
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# or a tag.
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if parts[-1].find('/') >= 0:
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# Last part is part of the hostname.
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return image_and_tag
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return '/'.join(parts[0:-1])
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def get_base_image_and_tag(self):
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from_commands = self.get_commands_of_kind('FROM')
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if not from_commands:
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return None
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return from_commands[0]['parameters']
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def strip_comments(contents):
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lines = [line for line in contents.split('\n') if not line.startswith(COMMENT_CHARACTER)]
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return '\n'.join(lines)
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def join_continued_lines(contents):
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return LINE_CONTINUATION_REGEX.sub('', contents)
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def parse_dockerfile(contents):
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contents = join_continued_lines(strip_comments(contents))
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lines = [line for line in contents.split('\n') if len(line) > 0]
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commands = []
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for line in lines:
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m = COMMAND_REGEX.match(line)
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if m:
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command = m.group(1)
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parameters = m.group(2)
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commands.append({
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'command': command,
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'parameters': parameters
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})
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return ParsedDockerfile(commands)
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