Adding to a list multiple times with set_fact

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1

Greetings fellow Ansible users!

I have a use case where I want to add values to a list dependant on host groups. I will then use the resulting list as an argument to another task.

It’s important than I don’t have duplicate values in the list, so I am using union() to add new items to the list, as indicated by http://docs.ansible.com/ansible/playbooks_filters.html

For some reason, as soon as a set_fact task is run against the same host and variable for a second time, Ansible explodes with an unintuitive Python/Jinja2 error, saying it’s getting a list when it doesn’t expect a list (which makes NO sense to me, because union() wants two lists are arguments surely?!).

fatal: [host4-uk] => Failed to template fruit=“{{ fruit | union([ ‘Goosberry’, ‘Blackberry’ ]) }}”: an unexpected type error occurred. Error was coercing to Unicode: need string or buffer, list found

Can anybody shed any light on this? Am I doing something particularly silly? Is there a better way to achieve what I want to do?

To illustrate the problem, I have tried to distill the issue down to this simple example:

nicola $ ls -1 *
fruit.yaml
inventory

group_vars:
all

nicola $ cat group_vars/all
fruit:
- UniversalFruit1-Foo

nicola $ cat inventory
[tropical]
host1-asia ansible_ssh_host=172.18.32.89
host2-asia ansible_ssh_host=172.18.97.157

[domestic]
host3-uk ansible_ssh_host=172.18.128.12
host4-uk ansible_ssh_host=172.18.128.13

[berries]
host4-uk ansible_ssh_host=172.18.128.13

nicola $ cat fruit.yaml

2

Hello,
How did you resolve this problem. I too faced the same thing but no resolution yet.

~Trupti