kv_diff.py

def kv_diff(A, B, whitelist=[]):
    '''
    Function can be used on elasticsearch mappings to identify variations.
    Returns a diff.
    Eg:
    template = requests.get(es_url + '/_template/mytemplate', auth=(es_user,es_pass)).json()['projects']['mappings']
    mapping = requests.get(es_url + '/foo/_mapping' % project_id, auth=(es_user,es_pass)).json()['foo']['mappings']
    kv_diff(template, mapping)
    '''
    try:
        retval = {}
        A_keys = A.keys()
        B_keys = B.keys()

        A_set = set(A_keys)
        B_set = set(B_keys)

        diff = A_set.symmetric_difference(B_set)

        intersection = A_set.intersection(B_set)
        intersection_copy = intersection.copy()

        for item in set(whitelist):
            if item in diff:
                diff.remove(item)
            if item in intersection:
                intersection_copy.remove(item)

        intersection = intersection_copy

        if diff:
            for item in diff:
                if item in A_keys:
                    retval['A'] = retval.get('A', {})
                    retval['A'][item] = A[item]
                if item in B_keys:
                    retval['B'] = retval.get('B', {})
                    retval['B'][item] = B[item]

        for key in intersection:
            kvdiff = kv_diff(A[key], B[key], whitelist)
            if kvdiff:
                retval[key] = kvdiff

        return retval

    except AttributeError:
        if A == B:
            return {}
        else:
            return {'A': A, 'B': B}

feedback appreciated!