variables

From time to time, I need to dynamically build a list of strings (or a list of other things) using Ansible's set_fact module.

Since set_fact is a module like any other, you can use a with_items loop to loop over an existing list, and pull out a value from that list to add to another list.

For example, today I needed to retrieve a list of all the AWS EC2 security groups in a region, then loop through them, building a list of all the security group names. Here's the playbook I used:

I recently ran into an issue where drush vset was not setting a string variable (in this case, a time period that would be used in strtotime()) correctly:

Using the --strict=0 option resulted in the variable being set to a value of "1".

After scratching my head a bit, trying different ways of escaping the string value, using single and double quotes, etc., I finally realized I could just use variable_set() with drush's php-eval command (shortcut ev):

This worked perfectly and allowed me to go make sure my time was successfully set to one day in the past.

In Drupal 6, I would often resort to using my theme's template.php file to implement template_preprocess(), and add in the class to Drupal's $body_classes array. In Drupal 7, some new hooks were introduced that allow me to do this more easily, and inside my .module files.

Introducing hook_preprocess_HOOK()