Ansible/Jinja: how to convert number to binary format

Question

I need to generate a random 128-bit number and get it's binary representation, b64-encoded.

Sample:

vagrant@ubuntu1804:~$ consul keygen
TUlzi8BWwPQR1zyjR1TiAQ==

in it's b64 decoded form:

vagrant@ubuntu1804:~$ consul keygen | base64 -d|hexdump -C
00000000  46 b8 72 4b ce 9a 2a 14  09 7b 16 51 99 1b 39 e0  |F�rK�.*..{.Q..9�|
00000010

I can generate the large number with random filter:

{{ 340282366920938463463374607431768211456 | random }}

I know I can encode it with b64encode, but have no idea how to convert the number to the binary format.

techraf · Answer 1 · 2018-07-11T15:00:39.837

2

Instead of converting (which is impossible as you can't store/process binary using native Ansible data structures), write a simple filter plugin (filter_plugins/myfilters.py) which would generate the content you want:

import os
import base64


class FilterModule(object):
    def filters(self):
        return {
            'binary_random_b64_encoded': self.binary_random_b64_encoded
        }

    def binary_random_b64_encoded(self, size):
        return base64.b64encode(os.urandom(size)).decode('ascii')

and use it (with the requested size of the binary data):

- debug:
    msg: "{{ 16 | binary_random_b64_encoded }}"

edited Jul 11 '18 at 15:00

answered Jul 11 '18 at 12:25

techraf

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this returns `b'O6hpZnFPlYjganye778Ydg=='`, any idea how to retype that? – Misko Jul 11 '18 at 13:54
I don't understand what you mean. `{{ 16 | binary_random_b64_encoded | type_debug }}` → `"msg": "str"` – techraf Jul 11 '18 at 14:23
1

adding `.decode('ascii')` to `base64.b64encode` did the job. – Misko Jul 11 '18 at 14:24
Oh, there's a difference between Python 2 and 3... updated. – techraf Jul 11 '18 at 14:49

Ansible/Jinja: how to convert number to binary format

1 Answers1