Map within a map in terraform variables - variables

Question

Does anyone know if it's possible with possibly code snipits representing whether I can create a map variable within a map variable in terraform variables?
variable "var" {
type = map
default = {
firstchoice = {
firstAChoice ="foo"
firstBChoice = "bar"
}
secondchoice = {
secondAChoice = "foobar"
secondBChoice = "barfoo"
}
}
}
If anyone has any insight to whether this is possible or any documentation that elaborates that would be great.

Answer 1

Yes, it's possible to have map variable as value of map variable key. Your variable just needed right indentation. Also I am putting ways to access that variable.
variable "var" {
default = {
firstchoice = {
firstAChoice = "foo"
firstBChoice = "bar"
}
secondchoice = {
secondAChoice = "foobar"
secondBChoice = "barfoo"
}
}
}
To access entire map value of a map key firstchoice, you can try following
value = "${var.var["firstchoice"]}"
output:
{
firstAChoice = foo
firstBChoice = bar
}
To access specific key of that map key (example firstAChoice), you can try
value = "${lookup(var.var["firstchoice"],"firstAChoice")}"
output: foo

Answer 2

Would this syntax be possible? ${var.var[firstchoice[firstAchoice]]}
With Terraform 0.12+ nested blocks are supported seamlessly. Extending #Avichal Badaya's answer to explain it using an example:
# Nested Variable
variable "test" {
default = {
firstchoice = {
firstAChoice = "foo"
firstBChoice = "bar"
}
secondchoice = {
secondAChoice = "foobar"
secondBChoice = "barfoo"
}
thirdchoice = {
thirdAChoice = {
thirdBChoice = {
thirdKey = "thirdValue"
}
}
}
}
}
# Outputs
output "firstchoice" {
value = var.test["firstchoice"]
}
output "FirstAChoice" {
value = var.test["firstchoice"]["firstAChoice"]
}
output "thirdKey" {
value = var.test["thirdchoice"]["thirdAChoice"]["thirdBChoice"]["thirdKey"]
}
Applying the above, you can verify that Terraform map nesting is now quite powerful and this makes a lot of things easier.
# Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
# Outputs:
firstchoice = {
"firstAChoice" = "foo"
"firstBChoice" = "bar"
}
thirdKey = thirdValue
For more complex structures and Rich Value Types, see HashiCorp Terraform 0.12 Preview: Rich Value Types