ansible: correct way to check a list of variables has been set?

Ansible: correct way to check a list of variables has been set?

To check if a list of variables has been set in Ansible, you can use the when conditional in a task. You can check each variable's existence and then act accordingly.

Example Playbook

Here's an example of how to check if a list of variables has been set:

--- - name: Check if a list of variables has been set hosts: localhost vars: my_vars: - var1 - var2 - var3 tasks: - name: Ensure all variables are defined debug: msg: "Variable {{ item }} is set." when: "{{ item | default(None) is not none }}" loop: "{{ my_vars }}" - name: Fail if any variable is not set fail: msg: "One or more variables are not set." when: > my_vars | select('length') != my_vars | length

Breakdown

  • my_vars: A list of variable names you want to check.
  • debug task: This task prints a message for each variable that is set.
    • when: This checks if the variable is not None using default.
    • loop: Loops through the list of variables.
  • fail task: This task fails if any of the variables are not set.
    • when: Compares the length of the filtered list to the original list.

Alternative Method

You can also use a set_fact task to create a single boolean variable to check if all variables are set:

--- - name: Check if a list of variables has been set hosts: localhost vars: var1: "value1" var2: "value2" var3: "" tasks: - name: Check if required variables are set set_fact: all_vars_set: >- var1 is defined and var2 is defined and var3 is defined and var1 | length > 0 and var2 | length > 0 and var3 | length > 0 - name: Fail if not all variables are set fail: msg: "One or more required variables are not set or are empty." when: not all_vars_set

Summary

  • Use a loop with the when condition to check if each variable is set.
  • Alternatively, consolidate checks into a boolean variable with set_fact and use a single conditional check to validate all variables at once.

Examples

  1. How to check if a variable is defined in Ansible? Description: Ansible provides a method to verify if a variable is defined before using it to prevent errors.

    {% raw %} {% if my_var is defined %} # Proceed with using my_var {% else %} # Handle case where my_var is not defined {% endif %} {% endraw %}

  2. Checking if multiple variables are defined in Ansible playbook? Description: You can verify the existence of multiple variables using the default filter to set a default value if a variable is not defined.

    {% raw %} {% if var1 is defined and var2 is defined %} # Proceed with using var1 and var2 {% else %} # Handle case where var1 or var2 is not defined {% endif %} {% endraw %}

  3. Ansible playbook check if list of variables are set? Description: Ensure all variables in a list are defined using a loop and conditional checks.

    {% raw %} {% for item in my_list %} {% if vars[item] is defined %} # Proceed with using vars[item] {% else %} # Handle case where vars[item] is not defined {% endif %} {% endfor %} {% endraw %}

  4. How to validate if a list of variables exists in Ansible? Description: Use default filter to check and set defaults for variables in a list.

    {% raw %} {% for var_name in list_of_vars %} {% set my_var = vars[var_name] | default(undefined_var) %} {% if my_var == undefined_var %} # Handle case where var_name is not defined {% else %} # Proceed with using my_var {% endif %} {% endfor %} {% endraw %}

  5. Best practice for checking if all variables are defined in Ansible tasks? Description: Use assert module to validate if all required variables are defined.

    {% raw %} - name: Check variables are defined assert: that: - var1 is defined - var2 is defined msg: 'Required variables are not defined' {% endraw %}

  6. How to handle undefined variables in Ansible playbook? Description: Handle undefined variables gracefully using default filter or default Jinja syntax.

    {% raw %} {% set my_var = vars.my_var | default('default_value') %} {% if my_var == 'default_value' %} # Handle case where my_var is not defined {% else %} # Proceed with using my_var {% endif %} {% endraw %}

  7. Ansible check if variable is empty or not set? Description: Verify if a variable is both defined and not empty before proceeding.

    {% raw %} {% if my_var is defined and my_var != '' %} # Proceed with using my_var {% else %} # Handle case where my_var is not defined or empty {% endif %} {% endraw %}

  8. Validating existence of multiple variables in Ansible playbook? Description: Use default filter in a loop to handle multiple variables.

    {% raw %} {% for item in my_list %} {% set my_var = vars[item] | default('default_value') %} {% if my_var == 'default_value' %} # Handle case where vars[item] is not defined {% else %} # Proceed with using my_var {% endif %} {% endfor %} {% endraw %}

  9. How to determine if a variable is defined in Ansible conditionals? Description: Use Jinja's conditional statements to check for variable existence.

    {% raw %} {% if my_var is defined %} # Proceed with using my_var {% else %} # Handle case where my_var is not defined {% endif %} {% endraw %}

  10. Checking if multiple variables are set in Ansible tasks? Description: Ensure multiple variables are set before executing tasks.

    {% raw %} - name: Check if variables are set assert: that: - var1 is defined - var2 is defined msg: 'Variables var1 and var2 must be defined' {% endraw %}

More Tags

code-behind httpcontent cookiestore lemmatization android-architecture safari keylogger local-files arcmap kdiff3

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