In Ansible, how to combine variables from separate files into one array?

Question:

In Ansible, in a role, I have vars files like this:

Each file contains vars specific to an app/website like this:

Ideally, without the task knowing in advance which apps have variable files, I’d like to end up with an array called apps like this:

ie, that combines the variables from the files into one.

I know I can load all the variable files like this:

But given each file has identical variable names, it will overwrite each previous set of variables. I can’t see a way to load the variables and put them into an apps array.

I’m open to rearranging things slightly if it’s the only way to make something like this possible.

Answer:

You can not do that. Variables will always override variables with the same name. The only thing you could do with this exact setup is to write your own vars plugin which reads those files and merges them into an array.

If you are open to change the structure of your apps definition you can use a hash and set your hash_behavior=merge. In each vars file then you’d have a definition like:


When Ansible loads both files it will merge it automatically together into:

But be advised that hash_behavior=merge fundamentally changes the default behavior of Ansible on a global level. Make sure all your roles do not have issues with this setting. The documentation mentions:

We generally recommend not using this setting unless you think you have an absolute need for it

If you still use Ansible 1 you could use one of my old plugins instead: include_vars_merged. Basically this adds the behavior of hash_behavior=merge to only a single task.

I have not yet looked into migrating this to Ansible 2 though and currently it looks like I won’t have the need for it any longer.

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