Source code for stacker.tokenize_userdata

from __future__ import print_function
from __future__ import division
from __future__ import absolute_import
import re

from troposphere import Ref, GetAtt


HELPERS = {
    "Ref": Ref,
    "Fn::GetAtt": GetAtt
}

split_string = "(" + "|".join([r"%s\([^)]+\)" % h for h in HELPERS]) + ")"
replace_string = \
    r"(?P<helper>%s)\((?P<args>['\"]?[^)]+['\"]?)+\)" % '|'.join(HELPERS)

split_re = re.compile(split_string)
replace_re = re.compile(replace_string)


[docs]def cf_tokenize(s): """ Parses UserData for Cloudformation helper functions. http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/user-data.html http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference.html http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/quickref-cloudformation.html#scenario-userdata-base64 It breaks apart the given string at each recognized function (see HELPERS) and instantiates the helper function objects in place of those. Returns a list of parts as a result. Useful when used with Join() and Base64() CloudFormation functions to produce user data. ie: Base64(Join('', cf_tokenize(userdata_string))) """ t = [] parts = split_re.split(s) for part in parts: cf_func = replace_re.search(part) if cf_func: args = [a.strip("'\" ") for a in cf_func.group("args").split(",")] t.append(HELPERS[cf_func.group("helper")](*args).data) else: t.append(part) return t