Create Terraform Cloudwatch Dashboards dynamically

Question

Overview

Currently, dashboards are being deployed via Terraform using values from a dictionary in locals.tf:

resource "aws_cloudwatch_dashboard" "my_alb" {
  for_each       = local.env_mapping[var.env]
  dashboard_name = "${each.key}_alb_web_operational"
  dashboard_body = templatefile("templates/alb_ops.tpl", {
    environment = each.value.env,
    account     = each.value.account,
    region      = each.value.region,
    alb         = each.value.alb
    tg          = each.value.alb_tg
  }

This leads to fragility because the values of AWS infrastructure resources like the ALB and ALB target group are hard coded. Sometimes when applying updates AWS resources are destroyed and recreated.

Question

What's the best approach to get these values dynamically? For example, this could be achieved by writing a Python/Boto3 Lambda, which looks up these values and then passes them to Terraform as env variables. Are there any other recommended ways to achieve the same?

Answer 1

To dynamically create CloudWatch dashboards in Terraform, you can use the aws_cloudwatch_dashboard resource in Terraform. You can define a Terraform template that creates the dashboard and its widgets, and use Terraform variables to pass in different values for each deployment.

Here's an example of how you can create a simple dashboard with a single line graph widget:

provider "aws" {
  region = "us-west-2"
}

variable "dashboard_name" {
  type = string
}

variable "widget_metric_name" {
  type = string
}

resource "aws_cloudwatch_dashboard" "example" {
  dashboard_name = var.dashboard_name

  dashboard_body = <<EOF
{
  "widgets": [
    {
      "type": "metric",
      "x": 0,
      "y": 0,
      "width": 12,
      "height": 6,
      "properties": {
        "metrics": [
          [ "AWS/EC2", "CPUUtilization", "InstanceId", "i-049df61146f277901" ],
          [ ".", ".", ".", "i-0682af8ca95c71c99" ]
        ],
        "period": 300,
        "stat": "Average",
        "region": "us-west-2",
        "title": "${var.widget_metric_name}"
      }
    }
  ]
}
EOF
}

You can deploy this Terraform template by running terraform apply and passing in the desired values for the dashboard_name and widget_metric_name variables. For example:

javascriptCopy code

terraform apply -var 'dashboard_name=MyDashboard' -var 'widget_metric_name=EC2 CPU Utilization'

This will create a new CloudWatch dashboard with the specified name and a single line graph widget displaying the average CPU utilization for two EC2 instances. You can modify the Terraform template to include additional widgets and customize the dashboard as desired.