Ansible random UUID generation - ansible

Question

In my Ansible script, I want to generate UUIDs on the fly and use them later on.
Here is my approach:
- shell: echo uuidgen
with_sequence: count=5
register: uuid_list
- uri:
url: http://www.myapi.com
method: POST
body: "{{ item.item.stdout }}"
with_items: uuid_list.result
However I get the following error:
fatal: [localhost] => One or more undefined variables: 'str object' has no attribute 'stdout'
How can I solve this issue?

Answer 1

In ansible 1.9 there is a new filter : to_uuid , which given a string it will return an ansible domain specific UUID,you can find the usage in here https://docs.ansible.com/playbooks_filters.html#other-useful-filters

Answer 2

As metioned by Xingxing Gao, there is to_uuid which can be used with a large enough number and the random filter to produce a random UUID. The larger the number the greater the randomness. eg:
{{ 99999999 | random | to_uuid }}
or
{{ 9999999999999999999999 | random | to_uuid }}

Answer 3

Generate a random UUID from a 20 char string with upper/lower case letters and digits:
{{ lookup('password', '/dev/null chars=ascii_letters,digits') | to_uuid }}

Answer 4

This is very close. I only had to change a few things. I figured this out by using the task "debug: var=uuid_list" and iterating.
- shell: uuidgen # note 1
with_sequence: count=5
register: uuid_list
- uri:
url: http://www.myapi.com
method: GET
body: "{{ item.stdout }}" # note 2
timeout: 1 # note 3
with_items: uuid_list.results # note 4
Notes:
echo caused the string uuidgen to be printed. removed echo, kept uuidgen.
item.item.stdout needed to be item.stdout
I used a short timeout so I could test this without having a rest endpoint available. This gives failure error messages but it's clear that it is correct.
uuid_list.stdout needed to be uuid_list.results

Answer 5

Be aware if you use Willem's solution, Jinja and Ansible will cache the result for multiple executions of the same filter, so you must change the source number each time
api_key_1: "{{ 999999999999999999995 | random | to_uuid }}"
api_key_2: "{{ 999999999999999999994 | random | to_uuid }}"
and for situations where you need a normal md5 instead of to_uuid, hash('md5') does not take an integer. The most convenient way to convert the random to a string I've found is to use to_uuid:
api_key_3: "{{ 999999999999999999999 | random | to_uuid | hash('md5') }}"
api_key_4: "{{ 999999999999999999998 | random | to_uuid | hash('md5') }}"

Answer 6

One solution which should be immune to caching/stale fact gathering and give you a reasonably random UUID each time you use it is:
{{ (999999999999999999999 | random | string + (lookup('pipe', 'date +%s%N'))) | to_uuid() }}
It concatenates a random number between 0 and 999999999999999999999 with current nanoseconds since Unix epoch and feeds that through Ansible's to_uuid() filter (available since version 1.9). Fact caching should not cause a problem as lookups are always evaluated each and every time they are invoked.
If you want a UUID that remains constant throughout the plays in a playbook (but doesn't persist between multiple invocations of the playbook - even with fact caching turned on) then use:
set_fact: uuid={{ (999999999999999999999 | random | string + (lookup('pipe', 'date +%s%N'))) | to_uuid() }}

Answer 7

I tried to avoid using the filter to_uuid, because it does not only take numbers as input but also characters. So, if I would only give it numbers as input, I would not be able to create every uuid possible.
I came up with this solution:
- name: Generate UUID
vars:
# This creates a random 128-bit integer and translates it to hexadecimal string.
# Zeros are put infront of the hex string, to make it always 32 hex-digits long.
__uuid: "{{ '%032x' % ((2**128) | random) }}"
# Format the hexadecimal string to a UUID format: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
uuid: "{{ __uuid[0:8] }}-{{ __uuid[8:12] }}-{{ __uuid[12:16] }}-{{ __uuid[16:20] }}-{{ __uuid[20:32] }}"
debug:
msg: "{{ uuid }}"