feat: map ssm_path with ssm version and detect changes of ssm parameter store's version (#7)

* feat: map ssm_path with ssm version and detect changes of ssm parameter store's version

* feat: code refactorization

Author: kandarpdave3

data.tf

@@ -9,6 +9,22 @@ data "aws_kms_alias" "ssm" {
   name = var.ssm_kms_alias
 }
 
+data "aws_ssm_parameter" "secret_env_vars" {
+  for_each = var.secret_environment_variables
+  name     = "${var.parameter_path_prefix}/${each.value}"
+}
+
+## Create map of "parameter_name => parameter_version" to detect the change of parameter's value
+resource "null_resource" "parameter_version_check" {
+  triggers = {
+    ssm_versions = jsonencode(
+      {
+        for parameter in data.aws_ssm_parameter.secret_env_vars : parameter.name => parameter.version
+      }
+    )
+  }
+}
+
 locals {
   aws_partition   = data.aws_partition.current.partition
   account_id      = data.aws_caller_identity.current.account_id
@@ -24,7 +40,7 @@ locals {
   secret_environment_variables = flatten([
     for name, valueFrom in var.secret_environment_variables : {
       name      = name
-      valueFrom = "${var.parameter_path_prefix}/${valueFrom}"
+      valueFrom = data.aws_ssm_parameter.secret_env_vars[name].name
     }
   ])
 }

main.tf

@@ -42,4 +42,11 @@ resource "aws_ecs_task_definition" "task" {
       }
     ]
   )
+
+  ## The resource will be restarted if null resource restarts 
+  lifecycle {
+    replace_triggered_by = [
+      null_resource.parameter_version_check
+    ]
+  }
 }