Strange behavior of Jinja2 expression for same input vars

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1

Hi All,

I’m using a Jinja2 expression to exclude form one list the elements present in another list but it doesn’t work as expected.

Here is an extract from a larger playbook which captures the input and out put before and after ‘set_fact’ statement:

`

  • debug: var=excluded_ids

  • debug: var=instance_ids

  • name: Exclude them from instance_ids
    set_fact: instance_ids1=“{% for item in instance_ids if item not in excluded_ids %}{{ item }}{% endfor %}”

  • debug: var=instance_ids1
    `

and here the strange output of instance_ids1 variable:

`
TASK: [debug var=excluded_ids] ************************************
ok: [127.0.0.1] => {
“var”: {
“excluded_ids”: [
“i-bae34407”
]
}
}

TASK: [debug var=instance_ids] ************************************
ok: [127.0.0.1] => {
“var”: {
“instance_ids”: [
“i-bae34407”,
“i-d2e4436f”
]
}
}

TASK: [Exclude them from instance_ids] ****************************
ok: [127.0.0.1] => {“ansible_facts”: {“instance_ids1”: “u, ud26f”}}

TASK: [debug var=instance_ids1] ***********************************
ok: [127.0.0.1] => {
“var”: {
“instance_ids1”: “u, ud26f”
}
}
`

As you can see I get some rubbish in instance_ids1.

But if I run a separate playbook defined like this:

`

2

have you tried the difference filter - http://docs.ansible.com/ansible/playbooks_filters.html

I’m not sure if you can combine a for loop and an if condition like that, I would have used something like this

set_fact: instance_ids1="{{ instance_ids | difference(excluded_ids) }}"

or

`
set_fact: instance_ids1=“{% for item in instance_ids %}{% if item not in excluded_ids %}{{ item }}{% endif %}{% endfor %}”

`

3

Thanks Aneesh,

The first suggestion brings this:

`
TASK: [Exclude them from instance_ids] ****************************
ok: [127.0.0.1] => {“ansible_facts”: {“instance_ids1”: “set([u’ ‘, u’d’, u’f’, u’,‘, u’2’, u’u’, u’6’])”}}

TASK: [debug var=instance_ids1] ***********************************
ok: [127.0.0.1] => {
“var”: {
“instance_ids1”: “set([u’ ‘, u’d’, u’f’, u’,‘, u’2’, u’u’, u’6’])”
}
}

`

the second one doesn’t work either (already tried before posting this :slight_smile: ).

Tested with Ansible version 1.9.4 & 2.2.0

4

Hey, tried both in 2.2.0 and they work for me

`

5

Yes, they work both in a test script where both the excluded_ids and instance_ids variables are defined manually but not in original playbook in which these variables are registered as outputs from other modules/tasks
despite the debug shows that their contents are the same.