libdevuansdk/extra/dockerfile_parse.py
2020-12-23 09:10:47 +01:00

148 lines
4.3 KiB
Python
Executable File

#!/usr/bin/env python3
# Copyright (c) 2018-2021 Ivan J. <parazyd@dyne.org>
# This file is part of libdevuansdk
#
# This source code is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This software 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this source code. If not, see <http://www.gnu.org/licenses/>.
"""
Dockerfile parser module
"""
from argparse import ArgumentParser
from sys import stdin
import json
import re
def rstrip_backslash(line):
"""
Strip backslashes from end of line
"""
line = line.rstrip()
if line.endswith('\\'):
return line[:-1]
return line
def parse_instruction(inst):
"""
Method for translating Dockerfile instructions to shell script
"""
ins = inst['instruction'].upper()
val = inst['value']
# Valid Dockerfile instructions
cmds = ['ADD', 'ARG', 'CMD', 'COPY', 'ENTRYPOINT', 'ENV', 'EXPOSE', 'FROM',
'HEALTHCHECK', 'LABEL', 'MAINTAINER', 'ONBUILD', 'RUN', 'SHELL',
'STOPSIGNAL', 'USER', 'VOLUME', 'WORKDIR']
if ins == 'ADD':
cmds.remove(ins)
val = val.replace('$', '\\$')
args = val.split(' ')
return 'wget -O %s %s\n' % (args[1], args[0])
elif ins == 'ARG':
cmds.remove(ins)
return '%s\n' % val
elif ins == 'ENV':
cmds.remove(ins)
if '=' not in val:
val = val.replace(' ', '=', 1)
return 'export %s\n' % val
elif ins == 'RUN':
cmds.remove(ins)
# Replace `` with $()
while '`' in val:
val = val.replace('`', '"$(', 1)
val = val.replace('`', ')"', 1)
return '%s\n' % val.replace('$', '\\$')
elif ins == 'WORKDIR':
cmds.remove(ins)
return 'mkdir -p %s && cd %s\n' % (val, val)
elif ins in cmds:
# TODO: Look at CMD being added to /etc/rc.local
return '#\n# %s not implemented\n# Instruction: %s %s\n#\n' % \
(ins, ins, val)
def main():
"""
Main parsing routine
"""
parser = ArgumentParser()
parser.add_argument('-j', '--json', action='store_true',
help='output the data as a JSON structure')
parser.add_argument('-s', '--shell', action='store_true',
help='output the data as a shell script (default)')
parser.add_argument('--keeptabs', action='store_true',
help='do not replace \\t (tabs) in the strings')
parser.add_argument('Dockerfile')
args = parser.parse_args()
if args.Dockerfile != '-':
with open(args.Dockerfile) as file:
data = file.read().splitlines()
else:
data = stdin.read().splitlines()
instre = re.compile(r'^\s*(\w+)\s+(.*)$')
contre = re.compile(r'^.*\\\s*$')
commentre = re.compile(r'^\s*#')
instructions = []
lineno = -1
in_continuation = False
cur_inst = {}
for line in data:
lineno += 1
if commentre.match(line):
continue
if not in_continuation:
rematch = instre.match(line)
if not rematch:
continue
cur_inst = {
'instruction': rematch.groups()[0].upper(),
'value': rstrip_backslash(rematch.groups()[1]),
}
else:
if cur_inst['value']:
cur_inst['value'] += rstrip_backslash(line)
else:
cur_inst['value'] = rstrip_backslash(line.lstrip())
in_continuation = contre.match(line)
if not in_continuation and cur_inst is not None:
if not args.keeptabs:
cur_inst['value'] = cur_inst['value'].replace('\t', '')
instructions.append(cur_inst)
if args.json:
print(json.dumps(instructions))
return
# Default to shell script output
script = '#!/bin/sh\n'
for i in instructions:
script += parse_instruction(i)
print(script)
if __name__ == '__main__':
main()