concourse extract

extract.py

#!/usr/bin/env python
# encoding: utf-8

import re
import sys
import yaml

parameter = re.compile(r'{{(.+)}}')
def extract(templated, complete):
    if isinstance(templated, list):
        assert len(templated) == len(complete)
        for first, second in zip(templated, complete):
            yield from extract(first, second)
    if isinstance(templated, dict):
        for key in set(templated.keys()).intersection(complete.keys()):
            yield from extract(templated[key], complete[key])
    if isinstance(templated, str):
        result = parameter.search(templated)
        if result:
            yield result.groups()[0], complete

replace = re.compile(r'({{[^\s]+}})')
def preprocess(stream):
    return replace.sub('"\\1"', stream.read())

if __name__ == '__main__':
    assert len(sys.argv) == 3
    templated = yaml.load(preprocess(open(sys.argv[1])))
    complete = yaml.load(open(sys.argv[2]))
    extracted = extract(templated, complete)
    for key, value in extract(templated, complete):
        print('{}: {}'.format(key, value))