Take ECS Task Definition environment variables from Terraform input variables - amazon-web-services

Question

I am trying to deploy ECS task definition with Terraform. Here is my ECS task definition resource code:
resource "aws_ecs_task_definition" "my_TD" {
family = "my_container"
container_definitions = <<DEFINITION
[{
"name": "my_container",
"image": "${format("%s:qa", var.my_ecr_arn)}",
"portMappings": [
{
"containerPort": 80,
"hostPort": 80
}
],
"memory": 300,
"networkMode": "awsvpc",
"environment": [
{
"name": "PORT",
"value": "80"
},
{
"name": "Token",
"value": "xxxxxxxx"
}
]
}
]
DEFINITION
requires_compatibilities = ["EC2"]
network_mode = "awsvpc"
cpu = "256"
memory = "512"
task_role_arn = var.ecs_role
execution_role_arn = var.ecs_role
}
The environment variables are hardcoded here. So, I tried to take those environment variables from terraform input. So, I modified with:
variable "my_env_variables"{
default = [
{
"name": "PORT",
"value": "80"
},
{
"name": "token",
"value": "xxxxx"
}
]
}
...
...
"environment" : "${var.my_env_variables}"
...
...
It's giving me an issue like this:
var.my_env_variables is tuple with 1 element
Cannot include the given value in a string template: string required.
I am new to Terraform. How can I solve this issue?

Answer 1

You need json string, which you can get using jsonencode. So you could try the following:
resource "aws_ecs_task_definition" "my_TD" {
family = "my_container"
container_definitions = <<DEFINITION
[{
"name": "my_container",
"image": "${format("%s:qa", var.my_ecr_arn)}",
"portMappings": [
{
"containerPort": 80,
"hostPort": 80
}
],
"memory": 300,
"networkMode": "awsvpc",
"environment": ${jsonencode(var.my_env_variables)}
}
]
DEFINITION
requires_compatibilities = ["EC2"]
network_mode = "awsvpc"
cpu = "256"
memory = "512"
task_role_arn = var.ecs_role
execution_role_arn = var.ecs_role
}