tImplement a python Dockerfile parser. - libdevuansdk - common library for devuan's simple distro kits
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---
DIR commit c922031a0cb2eade8922cf3c2d40dff2b13cd54c
DIR parent 2cf0d648bad5a2bfe0026158228d6e355a9b7e61
HTML Author: parazyd <parazyd@dyne.org>
Date: Tue, 18 Sep 2018 15:29:46 +0200
Implement a python Dockerfile parser.
This tool can translate Dockerfiles into shell scripts and JSON
structures. It is imagined to be used for the blend concept, where a
Dockerfile could be a system and can be translated into a blend file,
and used by an sdk.
Diffstat:
A extra/dockerfile_parse.py | 149 +++++++++++++++++++++++++++++++
1 file changed, 149 insertions(+), 0 deletions(-)
---
DIR diff --git a/extra/dockerfile_parse.py b/extra/dockerfile_parse.py
t@@ -0,0 +1,149 @@
+#!/usr/bin/env python
+# Copyright (c) 2018 Dyne.org Foundation
+# libdevuansdk is maintained by 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()