Python/DevOps

How do you apply changes in terraform ? In most cases you run terraform plan and then terraform apply  and type yes . This approach works great on your local machine, but how to apply changes (and only the changes you want!) in GitLab job where you do not have access to shell? How to do that, when you cannot approve the output of apply command? You can use terraform apply -auto-approve , but it might be risky... No one likes to destroy something on production without a priori knowledge. So, can we run terraform plan , check the output and then run terraform apply  in another step? We can, but still it might be risky operation. Why? Because plan and apply  are separated operations! They know nothing about each other. So, apply  can change something which was not showed in plan . But... according to Terraform Documentation : The optional -out argument can be used to save the generated plan to a file for later execution with terraform apply, which can be useful when running Terraform

In the previous post I had written about the include keyword. Now, let's dive in the extends  keyword. What can you do with this? Here is the definition from GitLab documentation: extends defines entry names that a job that uses extends inherits from. It’s an alternative to using YAML anchors and is a little more flexible and readable. So, when is it useful? It is useful when you want to be DRY and keep your setup cleanly. Let's assume that you want to build a docker image and give developers possibility to deploy the image on dev , staging and prod environments. We are going to do that without the extends keyword, and after that we will think how we can do it better. Example without the extends  keyword: As you can see, there is a lot of code which repeats itself: stage, image, when  and script . We can remove a lot of code! So, let's do that. We are going to create a hidden job .deploy  (you will not see this job in a pipeline) and the rest of the jobs will in