How do I ensure my .config and my jinja2 template stay in sync over time?

Question

We are using Ansible to deploy components and, in writing the jinja2 templates, it occurs to me that keeping my .config in sync with my .config.j2 is going to be something I need to "remember" going forward.

Are there better tools than "remembering" to keep the j2 in sync with the latest config files? I am open to all ideas... merge checks? Tests?

Answer 1

There are several things that you can do. Here are some of my ideas about how to do that.

1. Using a Makefile. With the help of that, instead of doing ansible-playbook -i BLAH BLAH BLAH playbok.yml, you just need to set few rules for that and with a simple command, something like make run-ansible all the steps from sync to apply ansible playbook works well for you.
   
   Take a look at this pseudo make file:

.PHONY : run-ansible run sync
sync:
    cp .config.j2 .confg
run:
    ansible-playbook -i host -u user playbook.yml
run-ansible: sync run

2. Use pre_tasks before running your role to update/sync .config file from .config.j2
3. Using conditional include. In case the .config is not updated, run another tasks which generate .config from .config.j2. Doing such a thing is so simple. This link could help you.