CODEWITHSUNDEEP
ansiblejinja2
tweeks200
tweeks200

Reputation: 1947

Jinja2 if/else matching both

I'm trying to use an if/else statement in an ansible template to populate values based on my hostname. I've written a module that parses the hostname and adds the values as facts. I'm able to use these facts in my playbooks but am having trouble getting an if/else statement to use them correctly. I end up with both the if and else matching so both values end up in my file.

jinja2 template

{% for host in groups['tag_Function_logfe'] %}
{% if hostvars[host]['tt_number'] == "01" %}
is_master = true
{% else %}
is_master = false
{% endif %}
{% endfor %}

Ansible Facts:

ok: [node1] => {"ansible_facts": {"tt_number": "01"}, "changed": false, "msg": "Additional facts added successfully"}
ok: [node2] => {"ansible_facts": {"tt_number": "02"}, "changed": false, "msg": "Additional facts added successfully"}

results:

is_master = true
is_master = false

Upvotes: 1

Views: 9403

Answers (1)

Anton Strogonoff
Anton Strogonoff

Reputation: 34032

I don’t have the full picture of what you’re trying to do overall, but Ansible and Jinja seem to behave as documented in this case so there might be a misunderstanding elsewhere.

You have a template that Ansible would render into a configuration file on every host. In this template, a for loop iterates over hosts in given group and declares is_master for each of those hosts. That would result in multiple definitions in every instance of the template, equal to the number of hosts in the “tag_Function_logfe“ group.

That doesn’t seem to make sense to me, since I’d assume there would be only one is_master definition per host.

Perhaps what you wanted to do instead is having this in the template:

{% if inventory_hostname in groups['tag_Function_logfe'] %}
    {% if tt_number == "01" %}
        is_master = true
    {% else %}
        is_master = false
    {% endif %}
{% endif %}

The inventory_hostname points to the host Ansible would be working with at the moment. We apparently want to check that this host belongs to the “tag_Function_logfe” group, and if it doesn’t we don’t define is_master at all.

Then we want to determine what value is_master should have based on tt_number. Note that we don’t need to use hostvars because we access tt_number’s value only for current host where the template is rendered into the configuration file.

It’s probably possible to further eliminate the group membership test, but that’s harder to tell without looking at the rest of the configuration.

Upvotes: 5

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