Learn how to build projects using Terraform.

DevOps for Developers

In this module, you will work from the ground up, starting with what Terraform is and the problems it solves. It will then guide you through the features of Terraform. You will build on your knowledge with the end goal of you being comfortable building projects using Terraform.

Terraform: From Beginner to Master with Examples in AWS

# Depends_on

We have seen thus far that, where possible, you should tell Terraform about dependencies by referring to one resource in the one that depends on it. The `depends_on` attribute offers a way to specify a dependency by hand. This can be useful if there is a
hidden dependency that Terraform would otherwise not know about.

## Example 

For example, if you are creating an S3 bucket and an IAM policy that allows writing to
the S3 bucket, then you should get the ARN of the S3 bucket from the property `aws_s3_bucket.arn` of the resource. 
In that case, Terraform will internally build a graph that the S3 bucket needs
to be created before the IAM role. There are some circumstances where there is a dependency that you cannot model like this, though. 

In those cases, you can explicitly tell Terraform that a resource depends
on another resource by using the `depends_on` attribute and then using the full path to the resource.

In this lesson, we'll discuss the depends_on attribute in detail.