03-inferences.md

Variables, output, inferences and dependencies

This section demonstrates several uses of variables, outputs, dependencies and inferences. It is very useful when creating terraform stacks; some of the ideas you can pick from here are:

• How to create a VCN, DHCP, Subnet, Security List, Routing Table, Internet Gateway
• How Terraform build the dependencies between resources with the terraform graph
• How you can create and delete resources with the various terraform commands
• the ability to add an file named *.auto.tfvars that is automatically used by terraform to populate variables from without having to use the -var-file parameter
• the fact that when a variable (see message) is a map, it can be set from different declarations and it results in the addition of all the declared keys
• the ability to create multiple resources from a single declaration with the count property (see oci_core_subnet)
• the ability to use count.index to loop through a list
• the use of a function like lookup to access a key in a map based on the value of a variable
• How you can create a list from a resource that uses count with the public_subnets output

You can move to the next section of this demonstration by running the command below:

git checkout -b 04-demo origin/04-demo