Скачать или смотреть Mastering Ansible: How to Use Variables in Conditional Statements Without Jinja2 Delimiters

Learn how to properly use variable references in Ansible's conditional statements without Jinja2 templating delimiters. Discover simple solutions to enhance your playbooks!
---
This video is based on the question https://stackoverflow.com/q/63320512/ asked by the user 'J H' ( https://stackoverflow.com/u/6178773/ ) and on the answer https://stackoverflow.com/a/63320598/ provided by the user 'larsks' ( https://stackoverflow.com/u/147356/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: ansible conditional statements should not include jinja2 templating delimiters

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mastering Ansible: How to Use Variables in Conditional Statements Without Jinja2 Delimiters

Ansible has revolutionized the way we automate our infrastructure. However, as with any powerful toolkit, mastering its features is crucial for effective usage. A common issue users encounter is surrounding conditional statements and the use of Jinja2 templating delimiters. Specifically, you might be wondering: What can I use to replace {{ }} while I still want to use variables?

Let's dive into this problem and outline a clear solution!

The Problem Explained

In Ansible, conditional statements are key for determining logic paths during playbook execution. A mistake many newcomers make is trying to use Jinja2 templating delimiters, like {{ variable_name }}, inside a when clause. This can lead to warnings or errors in your playbook. For example, you might encounter a warning like:

[WARNING]: conditional statements should not include jinja2 templating delimiters such as {{ }} or {% %}.

This warning indicates that the way you refer to variables needs adjustment.

Example of a Common Mistake

Here's a snippet that exemplifies the typical error:

[[See Video to Reveal this Text or Code Snippet]]

Each instance using the {{}} syntax in this conditional will trigger a warning, hindering your playbook's execution.

The Solution: Referencing Variables Correctly

What you need to understand is that within a when conditional, you are already operating in a context that understands Jinja2 syntax. Therefore, you should directly use the variable names without the curly braces. Here’s how you can rewrite the condition correctly:

[[See Video to Reveal this Text or Code Snippet]]

Breaking Down the Solution

Using Square Brackets:

The square bracket syntax [...] is necessary for dynamic keys. If you want the value of the variable resize_lvname to act as a key in the dictionary ansible_lvm.lvs, this syntax is essential.

Example:

ansible_lvm.lvs[resize_lvname] retrieves the value associated with resize_lvname from the dictionary.

Dot Notation vs. Bracket Notation:

While dot notation (e.g., some.var.key) can be used in many cases, it is a literal access method. If you write ansible_lvm.lvs.resize_lvname, you're attempting to access a key literally named resize_lvname, not the value of the variable.

Remember:

some.var.key is the same as some.var["key"], but when dynamic variables are involved, you must use the bracket notation.

Practical Tip:

To avoid warnings and to ensure that your Ansible playbooks run smoothly, always switch to this bracket syntax in conditional statements.

Conclusion

By mastering how to reference variables correctly in Ansible's conditional statements, you can enhance the logic of your playbooks and avoid common pitfalls. Keep this guideline handy whenever you're writing conditions, and soon, you'll find yourself navigating Ansible with greater ease and confidence.

If you have any questions or further issues related to Ansible, feel free to reach out or explore more in-depth guides on this topic. Happy automating!